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Help creating a simple calculator! - Java for Android App Development

Hello everyone I tried creating a simple calculator but when opening in my LWW it just force closes , so I am attaching the xmls and .java codes for your ready reference.
I am well versed in netbeans programming but new to android hence a helpful post will be really appreciated!
Bullet
MainActivity.java
Code:
package com.ptx.calcplus;
import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.widget.EditText;
public class MainActivity extends Activity {
private EditText txtNum1;
private EditText txtNum2;
private EditText txtAns;
double a = Double.parseDouble(txtNum1.getText().toString()) ;
double b = Double.parseDouble(txtNum2.getText().toString());
double c=0;
public void add(double a,double b)
{
c=a+b;
txtAns.setText(""+c);
return;
}
public void sub(double a,double b)
{
c=a-b;
txtAns.setText(""+c);
return;
}
public void div(double a,double b)
{
if(b==0)
{
txtAns.setText("Number 2 can't be 0!");
}
else{
c=a/b;
txtAns.setText(""+c);
return;
}
}
public void mul(double a,double b)
{
c=a*b;
txtAns.setText(""+c);
return;
}
[user=439709]@override[/user]
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
[user=439709]@override[/user]
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
strings.xml
Code:
<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="app_name">CalcPlus</string>
<string name="action_settings">Settings</string>
<string name="hello_world">Hello world!</string>
<string name="btnPlus">+</string>
<string name="btnSub">-</string>
<string name="btnMul">*</string>
<string name="btnDiv">/</string>
<string name="txtNum2">Enter number 2 here</string>
<string name="txtNum1">Enter number 1 here</string>
<string name="txtAns">Result</string>
</resources>
activity_main.xml
Code:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >
<Button
android:id="@+id/btnMul"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/btnSub"
android:layout_alignBottom="@+id/btnSub"
android:layout_alignParentLeft="true"
android:text="@string/btnMul"
android:onClick="mul" />
<Button
android:id="@+id/btnSub"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_marginBottom="127dp"
android:layout_toRightOf="@+id/btnMul"
android:text="@string/btnSub"
android:onClick="sub" />
<Button
android:id="@+id/btnAdd"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/btnSub"
android:layout_alignBottom="@+id/btnSub"
android:layout_toRightOf="@+id/btnSub"
android:text="@string/btnPlus"
android:onClick="add" />
<Button
android:id="@+id/btnDiv"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/btnAdd"
android:layout_alignBottom="@+id/btnAdd"
android:layout_toRightOf="@+id/btnAdd"
android:text="@string/btnDiv"
android:onClick="div"/>
<EditText
android:id="@+id/txtNum2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="@+id/btnMul"
android:layout_alignLeft="@+id/btnMul"
android:layout_alignRight="@+id/btnDiv"
android:layout_marginBottom="90dp"
android:ems="10"
android:hint="@string/txtNum2"
android:inputType="numberDecimal" />
<EditText
android:id="@+id/txtNum1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="@+id/txtNum2"
android:layout_alignLeft="@+id/txtNum2"
android:layout_alignRight="@+id/txtNum2"
android:layout_marginBottom="39dp"
android:ems="10"
android:hint="@string/txtNum1"
android:inputType="numberDecimal" >
<requestFocus />
</EditText>
<EditText
android:id="@+id/txtAns"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/txtNum2"
android:layout_alignRight="@+id/btnDiv"
android:layout_below="@+id/btnMul"
android:layout_marginTop="40dp"
android:ems="10"
android:enabled="false"
android:hint="@string/txtAns"
android:linksClickable="false" />
</RelativeLayout>
Manifest
Code:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.ptx.calcplus"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="17" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.ptx.calcplus.MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>

Hey BULLET, you seem to be on the right track but you've got a bit of tweaking to do.
Firstly, you need to tie all of your UI elements from XML to your activity. Do this in your on create method. My guess is that your force close is due to this line:
Code:
double a = Double.parseDouble(txtNum1.getText().toString()) ;
Your activity has no idea what txtNum1 is tied to, only that it is an EditText object. To set this up properly, keep your global edit text declarations and below is an example of what you'd add to your onCreate method:
Code:
txtNum1 = (EditText) findViewById(R.id.txtNum1);
You would need to do the same for your buttons and all of the elements that you have defined in your XML layout which you want to modify from your activity. (May I also suggest that you use a TextView instead of EditText to display the answer...)
Code:
Button buttonSubtract;
...
protected void onCreate(Bundle savedInstanceState) {
...
buttonSubtract = (Button) findViewById(R.id.btnSub);
...
}
You must also add methods for your buttons to wait for a click and perform the calculation methods you have written. To do this you would set up and onClickListener for each button.
I found TheNewBoston tutorials really handy when starting out. Here is an example of tying together the buttons and actions that they perform. It is very close to what you are trying to do.
http://www.youtube.com/watch?v=WjE-pWYElsE
Hope it helps. Feel free to ask any more questions.

Changed thing in accordance with video but still getting fc.
If possible could anyone paste the correct codes in my style?
BTW here are the code
strings.xml
Code:
<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="app_name">CalcPlus</string>
<string name="action_settings">Settings</string>
<string name="hello_world">Hello world!</string>
<string name="btnp">+</string>
<string name="btns">-</string>
<string name="btnm">*</string>
<string name="btnd">/</string>
<string name="txt2">Enter number 2 here</string>
<string name="txt1">Enter number 1 here</string>
<string name="txta">Result</string>
</resources>
MainActivity.java
Code:
package com.ptx.calcplus;
import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
public class MainActivity extends Activity {
private EditText txtN1;
private EditText txtN2;
private EditText txtAn;
Button Add,Sub,Div,Mul;
double a=Double.parseDouble(txtN1.getText().toString());
double b=Double.parseDouble(txtN2.getText().toString());
double c=0;
[user=439709]@override[/user]
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Add= (Button) findViewById(R.id.btnAdd);
Sub= (Button) findViewById(R.id.btnSub);
Div= (Button) findViewById(R.id.btnDiv);
Mul= (Button) findViewById(R.id.btnMul);
txtN1= (EditText) findViewById(R.id.txtNum1);
txtN2= (EditText) findViewById(R.id.txtNum2);
txtAn= (EditText) findViewById(R.id.txtAns);
Add.setOnClickListener(new View.OnClickListener() {
[user=439709]@override[/user]
public void onClick(View arg0) {
c=a+b;
txtAn.setText(""+c);
}
});
Sub.setOnClickListener(new View.OnClickListener() {
[user=439709]@override[/user]
public void onClick(View arg0) {
c=a+b;
txtAn.setText(""+c);
}
});
Mul.setOnClickListener(new View.OnClickListener() {
[user=439709]@override[/user]
public void onClick(View arg0) {
c=a+b;
txtAn.setText(""+c);
}
});
Div.setOnClickListener(new View.OnClickListener() {
[user=439709]@override[/user]
public void onClick(View arg0) {
c=a+b;
txtAn.setText(""+c);
}
});
}
[user=439709]@override[/user]
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
activity_main.xml
Code:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >
<Button
android:id="@+id/btnMul"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/btnSub"
android:layout_alignBottom="@+id/btnSub"
android:layout_alignParentLeft="true"
android:text="@string/btnm"
android:onClick="mul" />
<Button
android:id="@+id/btnSub"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_marginBottom="127dp"
android:layout_toRightOf="@+id/btnMul"
android:text="@string/btns"
android:onClick="sub" />
<Button
android:id="@+id/btnAdd"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/btnSub"
android:layout_alignBottom="@+id/btnSub"
android:layout_toRightOf="@+id/btnSub"
android:text="@string/btnp"
android:onClick="add" />
<Button
android:id="@+id/btnDiv"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/btnAdd"
android:layout_alignBottom="@+id/btnAdd"
android:layout_toRightOf="@+id/btnAdd"
android:text="@string/btnd"
android:onClick="div"/>
<EditText
android:id="@+id/txtNum2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="@+id/btnMul"
android:layout_alignLeft="@+id/btnMul"
android:layout_alignRight="@+id/btnDiv"
android:layout_marginBottom="90dp"
android:ems="10"
android:hint="@string/txt2"
android:inputType="numberDecimal" />
<EditText
android:id="@+id/txtNum1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="@+id/txtNum2"
android:layout_alignLeft="@+id/txtNum2"
android:layout_alignRight="@+id/txtNum2"
android:layout_marginBottom="39dp"
android:ems="10"
android:hint="@string/txt1"
android:inputType="numberDecimal" >
<requestFocus />
</EditText>
<EditText
android:id="@+id/txtAns"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/txtNum2"
android:layout_alignRight="@+id/btnDiv"
android:layout_below="@+id/btnMul"
android:layout_marginTop="40dp"
android:ems="10"
android:enabled="false"
android:hint="@string/txta"
android:linksClickable="false" />
</RelativeLayout>
Please please help me out!

I've fixed it up a little and it runs perfectly on my phone.
MainActivity.java
Code:
package com.ptx.calcplus;
import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
public class MainActivity extends Activity {
private EditText txtN1;
private EditText txtN2;
private EditText txtAn;
private Button Add, Sub, Div, Mul;
double a = 0, b = 0, c = 0;
[user=439709]@override[/user]
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Add = (Button) findViewById(R.id.btnAdd);
Sub = (Button) findViewById(R.id.btnSub);
Div = (Button) findViewById(R.id.btnDiv);
Mul = (Button) findViewById(R.id.btnMul);
txtN1 = (EditText) findViewById(R.id.txtNum1);
txtN2 = (EditText) findViewById(R.id.txtNum2);
txtAn = (EditText) findViewById(R.id.txtAns);
Add.setOnClickListener(new View.OnClickListener() {
[user=439709]@override[/user]
public void onClick(View arg0) {
a = Double.parseDouble(txtN1.getText().toString());
b = Double.parseDouble(txtN2.getText().toString());
c = a + b;
txtAn.setText(""+c);
}
});
Sub.setOnClickListener(new View.OnClickListener() {
[user=439709]@override[/user]
public void onClick(View arg0) {
a = Double.parseDouble(txtN1.getText().toString());
b = Double.parseDouble(txtN2.getText().toString());
txtAn.setText(""+c);
}
});
Mul.setOnClickListener(new View.OnClickListener() {
[user=439709]@override[/user]
public void onClick(View arg0) {
a = Double.parseDouble(txtN1.getText().toString());
b = Double.parseDouble(txtN2.getText().toString());
c = a * b;
txtAn.setText(""+c);
}
});
Div.setOnClickListener(new View.OnClickListener() {
[user=439709]@override[/user]
public void onClick(View arg0) {
a = Double.parseDouble(txtN1.getText().toString());
b = Double.parseDouble(txtN2.getText().toString());
c = a / b;
txtAn.setText(""+c);
}
});
}
[user=439709]@override[/user]
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
}
activity_main.xml
Code:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity" >
<Button
android:id="@+id/btnMul"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/btnSub"
android:layout_alignBottom="@+id/btnSub"
android:layout_alignParentLeft="true"
android:text="@string/btnm"
android:onClick="mul" />
<Button
android:id="@+id/btnSub"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_marginBottom="127dp"
android:layout_toRightOf="@+id/btnMul"
android:text="@string/btns"
android:onClick="sub" />
<Button
android:id="@+id/btnAdd"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/btnSub"
android:layout_alignBottom="@+id/btnSub"
android:layout_toRightOf="@+id/btnSub"
android:text="@string/btnp"
android:onClick="add" />
<Button
android:id="@+id/btnDiv"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/btnAdd"
android:layout_alignBottom="@+id/btnAdd"
android:layout_toRightOf="@+id/btnAdd"
android:text="@string/btnd"
android:onClick="div"/>
<EditText
android:id="@+id/txtNum2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="@+id/btnMul"
android:layout_alignLeft="@+id/btnMul"
android:layout_alignRight="@+id/btnDiv"
android:layout_marginBottom="90dp"
android:ems="10"
android:hint="@string/txt2"
android:inputType="numberDecimal" />
<EditText
android:id="@+id/txtNum1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="@+id/txtNum2"
android:layout_alignLeft="@+id/txtNum2"
android:layout_alignRight="@+id/txtNum2"
android:layout_marginBottom="39dp"
android:ems="10"
android:hint="@string/txt1"
android:inputType="numberDecimal" >
<requestFocus />
</EditText>
<EditText
android:id="@+id/txtAns"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/txtNum2"
android:layout_alignRight="@+id/btnDiv"
android:layout_below="@+id/btnMul"
android:layout_marginTop="40dp"
android:ems="10"
android:enabled="false"
android:hint="@string/txta"
android:linksClickable="false" />
</RelativeLayout>
I haven't touched the other files. Hope you get it working.

Works perfectly thank you.
Just tried to add dialog and clear, exit buttons but getting fc again. Please look into . I am really excited to make my first app.
Thank you once again
MainActivity.java
Code:
package com.ptx.calcplus;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
public class MainActivity extends Activity {
private EditText txtN1;
private EditText txtN2;
private EditText txtAn;
private Button Add, Sub, Div, Mul, Clr, Ext;
private AlertDialog.Builder dlgAlert = new AlertDialog.Builder(this);
double a = 0, b = 0, c = 0;
[user=439709]@override[/user]
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Add = (Button) findViewById(R.id.btnAdd);
Sub = (Button) findViewById(R.id.btnSub);
Div = (Button) findViewById(R.id.btnDiv);
Mul = (Button) findViewById(R.id.btnMul);
Clr = (Button) findViewById(R.id.btnClr);
Ext = (Button) findViewById(R.id.btnExt);
txtN1 = (EditText) findViewById(R.id.txtNum1);
txtN2 = (EditText) findViewById(R.id.txtNum2);
txtAn = (EditText) findViewById(R.id.txtAns);
Add.setOnClickListener(new View.OnClickListener() {
[user=439709]@override[/user]
public void onClick(View arg0) {
a = Double.parseDouble(txtN1.getText().toString());
b = Double.parseDouble(txtN2.getText().toString());
if(txtN1.getText().toString().isEmpty()||txtN2.getText().toString().isEmpty()){
dlgAlert.setMessage("Please enter number in text box!");
dlgAlert.setTitle("Enter Number");
dlgAlert.setPositiveButton("OK", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {}});
dlgAlert.setCancelable(true);
dlgAlert.create().show();
}
else{
c=a+b;
txtAn.setText(""+c);
}
}
});
Sub.setOnClickListener(new View.OnClickListener() {
[user=439709]@override[/user]
public void onClick(View arg0) {
a = Double.parseDouble(txtN1.getText().toString());
b = Double.parseDouble(txtN2.getText().toString());
if(txtN1.getText().toString().isEmpty()||txtN2.getText().toString().isEmpty()){
dlgAlert.setMessage("Please enter number in text box!");
dlgAlert.setTitle("Enter Number");
dlgAlert.setPositiveButton("OK", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {}});
dlgAlert.setCancelable(true);
dlgAlert.create().show();
}
else{
c=a-b;
txtAn.setText(""+c);
}
}
});
Mul.setOnClickListener(new View.OnClickListener() {
[user=439709]@override[/user]
public void onClick(View arg0) {
a = Double.parseDouble(txtN1.getText().toString());
b = Double.parseDouble(txtN2.getText().toString());
if(txtN1.getText().toString().isEmpty()||txtN2.getText().toString().isEmpty()){
dlgAlert.setMessage("Please enter number in text box!");
dlgAlert.setTitle("Enter Number");
dlgAlert.setPositiveButton("OK", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {}});
dlgAlert.setCancelable(true);
dlgAlert.create().show();
}
else{
c=a*b;
txtAn.setText(""+c);
}
}
});
Div.setOnClickListener(new View.OnClickListener() {
[user=439709]@override[/user]
public void onClick(View arg0) {
a = Double.parseDouble(txtN1.getText().toString());
b = Double.parseDouble(txtN2.getText().toString());
if(txtN1.getText().toString().isEmpty()||txtN2.getText().toString().isEmpty()){
dlgAlert.setMessage("Please enter number in text box!");
dlgAlert.setTitle("Enter Number");
dlgAlert.setPositiveButton("OK", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {}});
dlgAlert.setCancelable(true);
dlgAlert.create().show();
}
else if(b==0)
{
dlgAlert.setMessage("Number can not be zero");
dlgAlert.setTitle("Divider Zero!");
dlgAlert.setPositiveButton("OK", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {}});
dlgAlert.setCancelable(true);
dlgAlert.create().show();
}
else{
c=a+b;
txtAn.setText(""+c);
}
}
});
Clr.setOnClickListener(new View.OnClickListener() {
[user=439709]@override[/user]
public void onClick(View arg0) {
txtN1.setText("");
txtN2.setText("");
txtAn.setText("");
}
});
Ext.setOnClickListener(new View.OnClickListener() {
[user=439709]@override[/user]
public void onClick(View arg0) {
Intent intent = new Intent(Intent.ACTION_MAIN);
intent.addCategory(Intent.CATEGORY_HOME);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
}
});
}
[user=439709]@override[/user]
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
activity_main.xml
Code:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity" >
<Button
android:id="@+id/btnMul"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/btnSub"
android:layout_alignBottom="@+id/btnSub"
android:layout_alignParentLeft="true"
android:text="@string/btnm"
android:onClick="mul" />
<Button
android:id="@+id/btnSub"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_marginBottom="127dp"
android:layout_toRightOf="@+id/btnMul"
android:text="@string/btns"
android:onClick="sub" />
<Button
android:id="@+id/btnAdd"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/btnSub"
android:layout_alignBottom="@+id/btnSub"
android:layout_toRightOf="@+id/btnSub"
android:text="@string/btnp"
android:onClick="add" />
<Button
android:id="@+id/btnDiv"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/btnAdd"
android:layout_alignBottom="@+id/btnAdd"
android:layout_toRightOf="@+id/btnAdd"
android:text="@string/btnd"
android:onClick="div"/>
<EditText
android:id="@+id/txtNum2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="@+id/btnMul"
android:layout_alignLeft="@+id/btnMul"
android:layout_alignRight="@+id/btnDiv"
android:layout_marginBottom="90dp"
android:ems="10"
android:hint="@string/txt2"
android:inputType="numberDecimal" />
<EditText
android:id="@+id/txtNum1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="@+id/txtNum2"
android:layout_alignLeft="@+id/txtNum2"
android:layout_alignRight="@+id/txtNum2"
android:layout_marginBottom="39dp"
android:ems="10"
android:hint="@string/txt1"
android:inputType="numberDecimal" >
<requestFocus />
</EditText>
<EditText
android:id="@+id/txtAns"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_below="@+id/btnMul"
android:ems="10"
android:enabled="false"
android:hint="@string/txta"
android:linksClickable="false" />
<Button
android:id="@+id/btnClr"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignRight="@+id/btnSub"
android:layout_below="@+id/txtAns"
android:layout_marginTop="21dp"
android:text="@string/btnc"
android:onClick="clr" />
<Button
android:id="@+id/btnExt"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="@+id/btnClr"
android:layout_alignRight="@+id/txtAns"
android:text="@string/btne"
android:onClick="ext" />
</RelativeLayout>
Manifest
Code:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.ptx.calcplus"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="17" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.ptx.calcplus.MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
Strings.xml
Code:
<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="app_name">CalcPlus</string>
<string name="action_settings">Settings</string>
<string name="hello_world">Hello world!</string>
<string name="btnp">+</string>
<string name="btns">-</string>
<string name="btnm">*</string>
<string name="btnd">/</string>
<string name="txt2">Enter number 2 here</string>
<string name="txt1">Enter number 1 here</string>
<string name="txta">Result</string>
<string name="btnc">Clear</string>
<string name="btne">Exit</string>
</resources>
Please help me out!

Instead of having people fix your errors, how about posting your logcat so we can give you ideas on how to fix them. You won't learn how to debug by having other people do it for you. Also, on your exit button click, all you need to do is "finish();" the activity. You don't need to launch an intent because then your app technically never terminates.

zalez said:
Instead of having people fix your errors, how about posting your logcat so we can give you ideas on how to fix them. You won't learn how to debug by having other people do it for you. Also, on your exit button click, all you need to do is "finish();" the activity. You don't need to launch an intent because then your app technically never terminates.
Click to expand...
Click to collapse
So here is the logcat
Code:
04-23 10:31:20.509: E/Trace(3960): error opening trace file: No such file or directory (2)
04-23 10:32:31.009: E/AndroidRuntime(4130): ... 11 more

This is not the part of the logcat we need.
If you want to finish the activity from the Listener, use that:
Code:
MainActivity.this.finish();

nikwen said:
This is not the part of the logcat we need.
If you want to finish the activity from the Listener, use that:
Code:
MainActivity.this.finish();
Click to expand...
Click to collapse
Pl reply how to get a logcat in eclipse!!
Bullet

[==)BULLET(==] said:
Pl reply how to get a logcat in eclipse!!
Bullet
Click to expand...
Click to collapse
Check this: http://www.youtube.com/watch?v=2AHJsRKa_J8
Will have a closer look at your source code later.

nikwen said:
Check this: http://www.youtube.com/watch?v=2AHJsRKa_J8
Will have a closer look at your source code later.
Click to expand...
Click to collapse
Please put those Log.i(String String); in my code where ever it is appropriate.
Here is the whole logcat. Please help!
04-23 05:36:12.523: E/Trace(831): error opening trace file: No such file or directory (2)
04-23 05:36:12.863: D/AndroidRuntime(831): Shutting down VM
04-23 05:36:12.893: W/dalvikvm(831): threadid=1: thread exiting with uncaught exception (group=0x40a71930)
04-23 05:36:12.953: E/AndroidRuntime(831): FATAL EXCEPTION: main
04-23 05:36:12.953: E/AndroidRuntime(831): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.ptx.calcplus/com.ptx.calcplus.MainActivity}: java.lang.NullPointerException
04-23 05:36:12.953: E/AndroidRuntime(831): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2106)
04-23 05:36:12.953: E/AndroidRuntime(831): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
04-23 05:36:12.953: E/AndroidRuntime(831): at android.app.ActivityThread.access$600(ActivityThread.java:141)
04-23 05:36:12.953: E/AndroidRuntime(831): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
04-23 05:36:12.953: E/AndroidRuntime(831): at android.os.Handler.dispatchMessage(Handler.java:99)
04-23 05:36:12.953: E/AndroidRuntime(831): at android.os.Looper.loop(Looper.java:137)
04-23 05:36:12.953: E/AndroidRuntime(831): at android.app.ActivityThread.main(ActivityThread.java:5041)
04-23 05:36:12.953: E/AndroidRuntime(831): at java.lang.reflect.Method.invokeNative(Native Method)
04-23 05:36:12.953: E/AndroidRuntime(831): at java.lang.reflect.Method.invoke(Method.java:511)
04-23 05:36:12.953: E/AndroidRuntime(831): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
04-23 05:36:12.953: E/AndroidRuntime(831): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
04-23 05:36:12.953: E/AndroidRuntime(831): at dalvik.system.NativeStart.main(Native Method)
04-23 05:36:12.953: E/AndroidRuntime(831): Caused by: java.lang.NullPointerException
04-23 05:36:12.953: E/AndroidRuntime(831): at android.content.ContextWrapper.getApplicationInfo(ContextWrapper.java:140)
04-23 05:36:12.953: E/AndroidRuntime(831): at android.view.ContextThemeWrapper.getTheme(ContextThemeWrapper.java:103)
04-23 05:36:12.953: E/AndroidRuntime(831): at android.app.AlertDialog.resolveDialogTheme(AlertDialog.java:143)
04-23 05:36:12.953: E/AndroidRuntime(831): at android.app.AlertDialog$Builder.<init>(AlertDialog.java:360)
04-23 05:36:12.953: E/AndroidRuntime(831): at com.ptx.calcplus.MainActivity.<init>(MainActivity.java:17)
04-23 05:36:12.953: E/AndroidRuntime(831): at java.lang.Class.newInstanceImpl(Native Method)
04-23 05:36:12.953: E/AndroidRuntime(831): at java.lang.Class.newInstance(Class.java:1319)
04-23 05:36:12.953: E/AndroidRuntime(831): at android.app.Instrumentation.newActivity(Instrumentation.java:1054)
04-23 05:36:12.953: E/AndroidRuntime(831): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2097)
04-23 05:36:12.953: E/AndroidRuntime(831): ... 11 more
04-23 05:36:38.723: I/Process(831): Sending signal. PID: 831 SIG: 9
04-23 05:36:56.583: D/AndroidRuntime(867): Shutting down VM
04-23 05:36:56.644: W/dalvikvm(867): threadid=1: thread exiting with uncaught exception (group=0x40a71930)
04-23 05:36:56.673: E/AndroidRuntime(867): FATAL EXCEPTION: main
04-23 05:36:56.673: E/AndroidRuntime(867): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.ptx.calcplus/com.ptx.calcplus.MainActivity}: java.lang.NullPointerException
04-23 05:36:56.673: E/AndroidRuntime(867): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2106)
04-23 05:36:56.673: E/AndroidRuntime(867): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
04-23 05:36:56.673: E/AndroidRuntime(867): at android.app.ActivityThread.access$600(ActivityThread.java:141)
04-23 05:36:56.673: E/AndroidRuntime(867): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
04-23 05:36:56.673: E/AndroidRuntime(867): at android.os.Handler.dispatchMessage(Handler.java:99)
04-23 05:36:56.673: E/AndroidRuntime(867): at android.os.Looper.loop(Looper.java:137)
04-23 05:36:56.673: E/AndroidRuntime(867): at android.app.ActivityThread.main(ActivityThread.java:5041)
04-23 05:36:56.673: E/AndroidRuntime(867): at java.lang.reflect.Method.invokeNative(Native Method)
04-23 05:36:56.673: E/AndroidRuntime(867): at java.lang.reflect.Method.invoke(Method.java:511)
04-23 05:36:56.673: E/AndroidRuntime(867): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
04-23 05:36:56.673: E/AndroidRuntime(867): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
04-23 05:36:56.673: E/AndroidRuntime(867): at dalvik.system.NativeStart.main(Native Method)
04-23 05:36:56.673: E/AndroidRuntime(867): Caused by: java.lang.NullPointerException
04-23 05:36:56.673: E/AndroidRuntime(867): at android.content.ContextWrapper.getApplicationInfo(ContextWrapper.java:140)
04-23 05:36:56.673: E/AndroidRuntime(867): at android.view.ContextThemeWrapper.getTheme(ContextThemeWrapper.java:103)
04-23 05:36:56.673: E/AndroidRuntime(867): at android.app.AlertDialog.resolveDialogTheme(AlertDialog.java:143)
04-23 05:36:56.673: E/AndroidRuntime(867): at android.app.AlertDialog$Builder.<init>(AlertDialog.java:360)
04-23 05:36:56.673: E/AndroidRuntime(867): at com.ptx.calcplus.MainActivity.<init>(MainActivity.java:17)
04-23 05:36:56.673: E/AndroidRuntime(867): at java.lang.Class.newInstanceImpl(Native Method)
04-23 05:36:56.673: E/AndroidRuntime(867): at java.lang.Class.newInstance(Class.java:1319)
04-23 05:36:56.673: E/AndroidRuntime(867): at android.app.Instrumentation.newActivity(Instrumentation.java:1054)
04-23 05:36:56.673: E/AndroidRuntime(867): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2097)
04-23 05:36:56.673: E/AndroidRuntime(867): ... 11 more
04-23 05:37:00.153: I/Process(867): Sending signal. PID: 867 SIG: 9
04-23 05:37:16.343: E/Trace(884): error opening trace file: No such file or directory (2)
04-23 05:37:16.564: D/AndroidRuntime(884): Shutting down VM
04-23 05:37:16.564: W/dalvikvm(884): threadid=1: thread exiting with uncaught exception (group=0x40a71930)
04-23 05:37:16.613: E/AndroidRuntime(884): FATAL EXCEPTION: main
04-23 05:37:16.613: E/AndroidRuntime(884): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.ptx.calcplus/com.ptx.calcplus.MainActivity}: java.lang.NullPointerException
04-23 05:37:16.613: E/AndroidRuntime(884): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2106)
04-23 05:37:16.613: E/AndroidRuntime(884): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
04-23 05:37:16.613: E/AndroidRuntime(884): at android.app.ActivityThread.access$600(ActivityThread.java:141)
04-23 05:37:16.613: E/AndroidRuntime(884): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
04-23 05:37:16.613: E/AndroidRuntime(884): at android.os.Handler.dispatchMessage(Handler.java:99)
04-23 05:37:16.613: E/AndroidRuntime(884): at android.os.Looper.loop(Looper.java:137)
04-23 05:37:16.613: E/AndroidRuntime(884): at android.app.ActivityThread.main(ActivityThread.java:5041)
04-23 05:37:16.613: E/AndroidRuntime(884): at java.lang.reflect.Method.invokeNative(Native Method)
04-23 05:37:16.613: E/AndroidRuntime(884): at java.lang.reflect.Method.invoke(Method.java:511)
04-23 05:37:16.613: E/AndroidRuntime(884): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
04-23 05:37:16.613: E/AndroidRuntime(884): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
04-23 05:37:16.613: E/AndroidRuntime(884): at dalvik.system.NativeStart.main(Native Method)
04-23 05:37:16.613: E/AndroidRuntime(884): Caused by: java.lang.NullPointerException
04-23 05:37:16.613: E/AndroidRuntime(884): at android.content.ContextWrapper.getApplicationInfo(ContextWrapper.java:140)
04-23 05:37:16.613: E/AndroidRuntime(884): at android.view.ContextThemeWrapper.getTheme(ContextThemeWrapper.java:103)
04-23 05:37:16.613: E/AndroidRuntime(884): at android.app.AlertDialog.resolveDialogTheme(AlertDialog.java:143)
04-23 05:37:16.613: E/AndroidRuntime(884): at android.app.AlertDialog$Builder.<init>(AlertDialog.java:360)
04-23 05:37:16.613: E/AndroidRuntime(884): at com.ptx.calcplus.MainActivity.<init>(MainActivity.java:17)
04-23 05:37:16.613: E/AndroidRuntime(884): at java.lang.Class.newInstanceImpl(Native Method)
04-23 05:37:16.613: E/AndroidRuntime(884): at java.lang.Class.newInstance(Class.java:1319)
04-23 05:37:16.613: E/AndroidRuntime(884): at android.app.Instrumentation.newActivity(Instrumentation.java:1054)
04-23 05:37:16.613: E/AndroidRuntime(884): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2097)
04-23 05:37:16.613: E/AndroidRuntime(884): ... 11 more
04-23 05:38:20.383: D/AndroidRuntime(946): Shutting down VM
04-23 05:38:20.383: W/dalvikvm(946): threadid=1: thread exiting with uncaught exception (group=0x40a71930)
04-23 05:38:20.444: E/AndroidRuntime(946): FATAL EXCEPTION: main
04-23 05:38:20.444: E/AndroidRuntime(946): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.ptx.calcplus/com.ptx.calcplus.MainActivity}: java.lang.NullPointerException
04-23 05:38:20.444: E/AndroidRuntime(946): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2106)
04-23 05:38:20.444: E/AndroidRuntime(946): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
04-23 05:38:20.444: E/AndroidRuntime(946): at android.app.ActivityThread.access$600(ActivityThread.java:141)
04-23 05:38:20.444: E/AndroidRuntime(946): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
04-23 05:38:20.444: E/AndroidRuntime(946): at android.os.Handler.dispatchMessage(Handler.java:99)
04-23 05:38:20.444: E/AndroidRuntime(946): at android.os.Looper.loop(Looper.java:137)
04-23 05:38:20.444: E/AndroidRuntime(946): at android.app.ActivityThread.main(ActivityThread.java:5041)
04-23 05:38:20.444: E/AndroidRuntime(946): at java.lang.reflect.Method.invokeNative(Native Method)
04-23 05:38:20.444: E/AndroidRuntime(946): at java.lang.reflect.Method.invoke(Method.java:511)
04-23 05:38:20.444: E/AndroidRuntime(946): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
04-23 05:38:20.444: E/AndroidRuntime(946): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
04-23 05:38:20.444: E/AndroidRuntime(946): at dalvik.system.NativeStart.main(Native Method)
04-23 05:38:20.444: E/AndroidRuntime(946): Caused by: java.lang.NullPointerException
04-23 05:38:20.444: E/AndroidRuntime(946): at android.content.ContextWrapper.getApplicationInfo(ContextWrapper.java:140)
04-23 05:38:20.444: E/AndroidRuntime(946): at android.view.ContextThemeWrapper.getTheme(ContextThemeWrapper.java:103)
04-23 05:38:20.444: E/AndroidRuntime(946): at android.app.AlertDialog.resolveDialogTheme(AlertDialog.java:143)
04-23 05:38:20.444: E/AndroidRuntime(946): at android.app.AlertDialog$Builder.<init>(AlertDialog.java:360)
04-23 05:38:20.444: E/AndroidRuntime(946): at com.ptx.calcplus.MainActivity.<init>(MainActivity.java:17)
04-23 05:38:20.444: E/AndroidRuntime(946): at java.lang.Class.newInstanceImpl(Native Method)
04-23 05:38:20.444: E/AndroidRuntime(946): at java.lang.Class.newInstance(Class.java:1319)
04-23 05:38:20.444: E/AndroidRuntime(946): at android.app.Instrumentation.newActivity(Instrumentation.java:1054)
04-23 05:38:20.444: E/AndroidRuntime(946): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2097)
04-23 05:38:20.444: E/AndroidRuntime(946): ... 11 more
04-23 05:50:13.903: E/Trace(1245): error opening trace file: No such file or directory (2)
04-23 05:50:14.063: D/AndroidRuntime(1245): Shutting down VM
04-23 05:50:14.103: W/dalvikvm(1245): threadid=1: thread exiting with uncaught exception (group=0x40a71930)
04-23 05:50:14.133: E/AndroidRuntime(1245): FATAL EXCEPTION: main
04-23 05:50:14.133: E/AndroidRuntime(1245): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.ptx.calcplus/com.ptx.calcplus.MainActivity}: java.lang.NullPointerException
04-23 05:50:14.133: E/AndroidRuntime(1245): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2106)
04-23 05:50:14.133: E/AndroidRuntime(1245): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
04-23 05:50:14.133: E/AndroidRuntime(1245): at android.app.ActivityThread.access$600(ActivityThread.java:141)
04-23 05:50:14.133: E/AndroidRuntime(1245): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
04-23 05:50:14.133: E/AndroidRuntime(1245): at android.os.Handler.dispatchMessage(Handler.java:99)
04-23 05:50:14.133: E/AndroidRuntime(1245): at android.os.Looper.loop(Looper.java:137)
04-23 05:50:14.133: E/AndroidRuntime(1245): at android.app.ActivityThread.main(ActivityThread.java:5041)
04-23 05:50:14.133: E/AndroidRuntime(1245): at java.lang.reflect.Method.invokeNative(Native Method)
04-23 05:50:14.133: E/AndroidRuntime(1245): at java.lang.reflect.Method.invoke(Method.java:511)
04-23 05:50:14.133: E/AndroidRuntime(1245): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
04-23 05:50:14.133: E/AndroidRuntime(1245): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
04-23 05:50:14.133: E/AndroidRuntime(1245): at dalvik.system.NativeStart.main(Native Method)
04-23 05:50:14.133: E/AndroidRuntime(1245): Caused by: java.lang.NullPointerException
04-23 05:50:14.133: E/AndroidRuntime(1245): at android.content.ContextWrapper.getApplicationInfo(ContextWrapper.java:140)
04-23 05:50:14.133: E/AndroidRuntime(1245): at android.view.ContextThemeWrapper.getTheme(ContextThemeWrapper.java:103)
04-23 05:50:14.133: E/AndroidRuntime(1245): at android.app.AlertDialog.resolveDialogTheme(AlertDialog.java:143)
04-23 05:50:14.133: E/AndroidRuntime(1245): at android.app.AlertDialog$Builder.<init>(AlertDialog.java:360)
04-23 05:50:14.133: E/AndroidRuntime(1245): at com.ptx.calcplus.MainActivity.<init>(MainActivity.java:17)
04-23 05:50:14.133: E/AndroidRuntime(1245): at java.lang.Class.newInstanceImpl(Native Method)
04-23 05:50:14.133: E/AndroidRuntime(1245): at java.lang.Class.newInstance(Class.java:1319)
04-23 05:50:14.133: E/AndroidRuntime(1245): at android.app.Instrumentation.newActivity(Instrumentation.java:1054)
04-23 05:50:14.133: E/AndroidRuntime(1245): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2097)
04-23 05:50:14.133: E/AndroidRuntime(1245): ... 11 more
04-23 05:50:14.223: I/Process(1245): Sending signal. PID: 1245 SIG: 9
04-23 05:50:24.554: E/Trace(1262): error opening trace file: No such file or directory (2)
04-23 05:50:24.754: D/AndroidRuntime(1262): Shutting down VM
04-23 05:50:24.764: W/dalvikvm(1262): threadid=1: thread exiting with uncaught exception (group=0x40a71930)
04-23 05:50:24.814: E/AndroidRuntime(1262): FATAL EXCEPTION: main
04-23 05:50:24.814: E/AndroidRuntime(1262): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.ptx.calcplus/com.ptx.calcplus.MainActivity}: java.lang.NullPointerException
04-23 05:50:24.814: E/AndroidRuntime(1262): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2106)
04-23 05:50:24.814: E/AndroidRuntime(1262): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
04-23 05:50:24.814: E/AndroidRuntime(1262): at android.app.ActivityThread.access$600(ActivityThread.java:141)
04-23 05:50:24.814: E/AndroidRuntime(1262): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
04-23 05:50:24.814: E/AndroidRuntime(1262): at android.os.Handler.dispatchMessage(Handler.java:99)
04-23 05:50:24.814: E/AndroidRuntime(1262): at android.os.Looper.loop(Looper.java:137)
04-23 05:50:24.814: E/AndroidRuntime(1262): at android.app.ActivityThread.main(ActivityThread.java:5041)
04-23 05:50:24.814: E/AndroidRuntime(1262): at java.lang.reflect.Method.invokeNative(Native Method)
04-23 05:50:24.814: E/AndroidRuntime(1262): at java.lang.reflect.Method.invoke(Method.java:511)
04-23 05:50:24.814: E/AndroidRuntime(1262): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
04-23 05:50:24.814: E/AndroidRuntime(1262): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
04-23 05:50:24.814: E/AndroidRuntime(1262): at dalvik.system.NativeStart.main(Native Method)
04-23 05:50:24.814: E/AndroidRuntime(1262): Caused by: java.lang.NullPointerException
04-23 05:50:24.814: E/AndroidRuntime(1262): at android.content.ContextWrapper.getApplicationInfo(ContextWrapper.java:140)
04-23 05:50:24.814: E/AndroidRuntime(1262): at android.view.ContextThemeWrapper.getTheme(ContextThemeWrapper.java:103)
04-23 05:50:24.814: E/AndroidRuntime(1262): at android.app.AlertDialog.resolveDialogTheme(AlertDialog.java:143)
04-23 05:50:24.814: E/AndroidRuntime(1262): at android.app.AlertDialog$Builder.<init>(AlertDialog.java:360)
04-23 05:50:24.814: E/AndroidRuntime(1262): at com.ptx.calcplus.MainActivity.<init>(MainActivity.java:17)
04-23 05:50:24.814: E/AndroidRuntime(1262): at java.lang.Class.newInstanceImpl(Native Method)
04-23 05:50:24.814: E/AndroidRuntime(1262): at java.lang.Class.newInstance(Class.java:1319)
04-23 05:50:24.814: E/AndroidRuntime(1262): at android.app.Instrumentation.newActivity(Instrumentation.java:1054)
04-23 05:50:24.814: E/AndroidRuntime(1262): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2097)
04-23 05:50:24.814: E/AndroidRuntime(1262): ... 11 more
04-23 05:53:39.893: E/Trace(1352): error opening trace file: No such file or directory (2)
04-23 05:53:40.044: D/AndroidRuntime(1352): Shutting down VM
04-23 05:53:40.044: W/dalvikvm(1352): threadid=1: thread exiting with uncaught exception (group=0x40a71930)
04-23 05:53:40.063: E/AndroidRuntime(1352): FATAL EXCEPTION: main
04-23 05:53:40.063: E/AndroidRuntime(1352): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.ptx.calcplus/com.ptx.calcplus.MainActivity}: java.lang.NullPointerException
04-23 05:53:40.063: E/AndroidRuntime(1352): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2106)
04-23 05:53:40.063: E/AndroidRuntime(1352): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
04-23 05:53:40.063: E/AndroidRuntime(1352): at android.app.ActivityThread.access$600(ActivityThread.java:141)
04-23 05:53:40.063: E/AndroidRuntime(1352): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
04-23 05:53:40.063: E/AndroidRuntime(1352): at android.os.Handler.dispatchMessage(Handler.java:99)
04-23 05:53:40.063: E/AndroidRuntime(1352): at android.os.Looper.loop(Looper.java:137)
04-23 05:53:40.063: E/AndroidRuntime(1352): at android.app.ActivityThread.main(ActivityThread.java:5041)
04-23 05:53:40.063: E/AndroidRuntime(1352): at java.lang.reflect.Method.invokeNative(Native Method)
04-23 05:53:40.063: E/AndroidRuntime(1352): at java.lang.reflect.Method.invoke(Method.java:511)
04-23 05:53:40.063: E/AndroidRuntime(1352): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
04-23 05:53:40.063: E/AndroidRuntime(1352): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
04-23 05:53:40.063: E/AndroidRuntime(1352): at dalvik.system.NativeStart.main(Native Method)
04-23 05:53:40.063: E/AndroidRuntime(1352): Caused by: java.lang.NullPointerException
04-23 05:53:40.063: E/AndroidRuntime(1352): at android.content.ContextWrapper.getApplicationInfo(ContextWrapper.java:140)
04-23 05:53:40.063: E/AndroidRuntime(1352): at android.view.ContextThemeWrapper.getTheme(ContextThemeWrapper.java:103)
04-23 05:53:40.063: E/AndroidRuntime(1352): at android.app.AlertDialog.resolveDialogTheme(AlertDialog.java:143)
04-23 05:53:40.063: E/AndroidRuntime(1352): at android.app.AlertDialog$Builder.<init>(AlertDialog.java:360)
04-23 05:53:40.063: E/AndroidRuntime(1352): at com.ptx.calcplus.MainActivity.<init>(MainActivity.java:17)
04-23 05:53:40.063: E/AndroidRuntime(1352): at java.lang.Class.newInstanceImpl(Native Method)
04-23 05:53:40.063: E/AndroidRuntime(1352): at java.lang.Class.newInstance(Class.java:1319)
04-23 05:53:40.063: E/AndroidRuntime(1352): at android.app.Instrumentation.newActivity(Instrumentation.java:1054)
04-23 05:53:40.063: E/AndroidRuntime(1352): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2097)
04-23 05:53:40.063: E/AndroidRuntime(1352): ... 11 more
04-23 05:53:40.106: I/Process(1352): Sending signal. PID: 1352 SIG: 9
04-23 05:57:17.853: D/AndroidRuntime(1452): Shutting down VM
04-23 05:57:17.853: W/dalvikvm(1452): threadid=1: thread exiting with uncaught exception (group=0x40a71930)
04-23 05:57:17.873: E/AndroidRuntime(1452): FATAL EXCEPTION: main
04-23 05:57:17.873: E/AndroidRuntime(1452): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.ptx.calcplus/com.ptx.calcplus.MainActivity}: java.lang.NullPointerException
04-23 05:57:17.873: E/AndroidRuntime(1452): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2106)
04-23 05:57:17.873: E/AndroidRuntime(1452): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
04-23 05:57:17.873: E/AndroidRuntime(1452): at android.app.ActivityThread.access$600(ActivityThread.java:141)
04-23 05:57:17.873: E/AndroidRuntime(1452): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
04-23 05:57:17.873: E/AndroidRuntime(1452): at android.os.Handler.dispatchMessage(Handler.java:99)
04-23 05:57:17.873: E/AndroidRuntime(1452): at android.os.Looper.loop(Looper.java:137)
04-23 05:57:17.873: E/AndroidRuntime(1452): at android.app.ActivityThread.main(ActivityThread.java:5041)
04-23 05:57:17.873: E/AndroidRuntime(1452): at java.lang.reflect.Method.invokeNative(Native Method)
04-23 05:57:17.873: E/AndroidRuntime(1452): at java.lang.reflect.Method.invoke(Method.java:511)
04-23 05:57:17.873: E/AndroidRuntime(1452): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
04-23 05:57:17.873: E/AndroidRuntime(1452): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
04-23 05:57:17.873: E/AndroidRuntime(1452): at dalvik.system.NativeStart.main(Native Method)
04-23 05:57:17.873: E/AndroidRuntime(1452): Caused by: java.lang.NullPointerException
04-23 05:57:17.873: E/AndroidRuntime(1452): at android.content.ContextWrapper.getApplicationInfo(ContextWrapper.java:140)
04-23 05:57:17.873: E/AndroidRuntime(1452): at android.view.ContextThemeWrapper.getTheme(ContextThemeWrapper.java:103)
04-23 05:57:17.873: E/AndroidRuntime(1452): at android.app.AlertDialog.resolveDialogTheme(AlertDialog.java:143)
04-23 05:57:17.873: E/AndroidRuntime(1452): at android.app.AlertDialog$Builder.<init>(AlertDialog.java:360)
04-23 05:57:17.873: E/AndroidRuntime(1452): at com.ptx.calcplus.MainActivity.<init>(MainActivity.java:18)
04-23 05:57:17.873: E/AndroidRuntime(1452): at java.lang.Class.newInstanceImpl(Native Method)
04-23 05:57:17.873: E/AndroidRuntime(1452): at java.lang.Class.newInstance(Class.java:1319)
04-23 05:57:17.873: E/AndroidRuntime(1452): at android.app.Instrumentation.newActivity(Instrumentation.java:1054)
04-23 05:57:17.873: E/AndroidRuntime(1452): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2097)
04-23 05:57:17.873: E/AndroidRuntime(1452): ... 11 more
Click to expand...
Click to collapse

[==)BULLET(==] said:
Please put those Log.i(String String); in my code where ever it is appropriate.
Here is the whole logcat. Please help!
Click to expand...
Click to collapse
They are not needed. I just wanted to show you how to get the log.
I will check the code later on my computer.
Thanks for the log.
---------- Post added at 03:04 PM ---------- Previous post was at 02:10 PM ----------
[==)BULLET(==] said:
Works perfectly thank you.
Just tried to add dialog and clear, exit buttons but getting fc again. Please look into . I am really excited to make my first app.
Thank you once again
MainActivity.java
Code:
package com.ptx.calcplus;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
public class MainActivity extends Activity {
private EditText txtN1;
private EditText txtN2;
private EditText txtAn;
private Button Add, Sub, Div, Mul, Clr, Ext;
private AlertDialog.Builder dlgAlert = new AlertDialog.Builder(this);
double a = 0, b = 0, c = 0;
[user=439709]@override[/user]
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Add = (Button) findViewById(R.id.btnAdd);
Sub = (Button) findViewById(R.id.btnSub);
Div = (Button) findViewById(R.id.btnDiv);
Mul = (Button) findViewById(R.id.btnMul);
Clr = (Button) findViewById(R.id.btnClr);
Ext = (Button) findViewById(R.id.btnExt);
txtN1 = (EditText) findViewById(R.id.txtNum1);
txtN2 = (EditText) findViewById(R.id.txtNum2);
txtAn = (EditText) findViewById(R.id.txtAns);
Add.setOnClickListener(new View.OnClickListener() {
[user=439709]@override[/user]
public void onClick(View arg0) {
a = Double.parseDouble(txtN1.getText().toString());
b = Double.parseDouble(txtN2.getText().toString());
if(txtN1.getText().toString().isEmpty()||txtN2.getText().toString().isEmpty()){
dlgAlert.setMessage("Please enter number in text box!");
dlgAlert.setTitle("Enter Number");
dlgAlert.setPositiveButton("OK", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {}});
dlgAlert.setCancelable(true);
dlgAlert.create().show();
}
else{
c=a+b;
txtAn.setText(""+c);
}
}
});
Sub.setOnClickListener(new View.OnClickListener() {
[user=439709]@override[/user]
public void onClick(View arg0) {
a = Double.parseDouble(txtN1.getText().toString());
b = Double.parseDouble(txtN2.getText().toString());
if(txtN1.getText().toString().isEmpty()||txtN2.getText().toString().isEmpty()){
dlgAlert.setMessage("Please enter number in text box!");
dlgAlert.setTitle("Enter Number");
dlgAlert.setPositiveButton("OK", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {}});
dlgAlert.setCancelable(true);
dlgAlert.create().show();
}
else{
c=a-b;
txtAn.setText(""+c);
}
}
});
Mul.setOnClickListener(new View.OnClickListener() {
[user=439709]@override[/user]
public void onClick(View arg0) {
a = Double.parseDouble(txtN1.getText().toString());
b = Double.parseDouble(txtN2.getText().toString());
if(txtN1.getText().toString().isEmpty()||txtN2.getText().toString().isEmpty()){
dlgAlert.setMessage("Please enter number in text box!");
dlgAlert.setTitle("Enter Number");
dlgAlert.setPositiveButton("OK", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {}});
dlgAlert.setCancelable(true);
dlgAlert.create().show();
}
else{
c=a*b;
txtAn.setText(""+c);
}
}
});
Div.setOnClickListener(new View.OnClickListener() {
[user=439709]@override[/user]
public void onClick(View arg0) {
a = Double.parseDouble(txtN1.getText().toString());
b = Double.parseDouble(txtN2.getText().toString());
if(txtN1.getText().toString().isEmpty()||txtN2.getText().toString().isEmpty()){
dlgAlert.setMessage("Please enter number in text box!");
dlgAlert.setTitle("Enter Number");
dlgAlert.setPositiveButton("OK", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {}});
dlgAlert.setCancelable(true);
dlgAlert.create().show();
}
else if(b==0)
{
dlgAlert.setMessage("Number can not be zero");
dlgAlert.setTitle("Divider Zero!");
dlgAlert.setPositiveButton("OK", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {}});
dlgAlert.setCancelable(true);
dlgAlert.create().show();
}
else{
c=a+b;
txtAn.setText(""+c);
}
}
});
Clr.setOnClickListener(new View.OnClickListener() {
[user=439709]@override[/user]
public void onClick(View arg0) {
txtN1.setText("");
txtN2.setText("");
txtAn.setText("");
}
});
Ext.setOnClickListener(new View.OnClickListener() {
[user=439709]@override[/user]
public void onClick(View arg0) {
Intent intent = new Intent(Intent.ACTION_MAIN);
intent.addCategory(Intent.CATEGORY_HOME);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
}
});
}
[user=439709]@override[/user]
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
Please help me out!
Click to expand...
Click to collapse
It is a similar mistake. You cannot do anything related with Android views in your field declarations.
You need to do it in your onCreate method, if you load the layout from a xml, after the setContentView method. So change it to this:
MainActivity.java
Code:
package com.ptx.calcplus;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
public class MainActivity extends Activity {
private EditText txtN1;
private EditText txtN2;
private EditText txtAn;
private Button Add, Sub, Div, Mul, Clr, Ext;
private AlertDialog.Builder dlgAlert;
double a = 0, b = 0, c = 0;
[user=439709]@override[/user]
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Add = (Button) findViewById(R.id.btnAdd);
... //your other stuff
dlgAlert = new AlertDialog.Builder(this);
...
This should work. Try it.

You're targetting min sdk of 8, which doesn't allow checking if string ".isEmpty()", which IF I'M NOT WRONG, is not included in older version of Android due to different version of Java. So I've changed it to check if the length is less than 0 before calculating.
Code:
.length() < 1
Secondly, you're converting the values of the Textbox BEFORE you check if the input is empty or not. Check before converting. Because if your input is empty, it is unable to convert a NULL into a double.
Lastly, one small error. Your DIVIDE is still PLUS. I've corrected it for you.
Sorry for the late reply! Hope there ain't any error.
Oh, one small tip. Try reading up "Try and Catch" for Android. Good for preventing force closing of apps.
Code:
package com.example.caltest;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
public class MainActivity extends Activity {
private EditText txtN1;
private EditText txtN2;
private EditText txtAn;
private Button Add, Sub, Div, Mul, Clr, Ext;
private AlertDialog.Builder dlgAlert;
double a = 0, b = 0, c = 0;
[user=439709]@override[/user]
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
dlgAlert = new AlertDialog.Builder(MainActivity.this);
Add = (Button) findViewById(R.id.btnAdd);
Sub = (Button) findViewById(R.id.btnSub);
Div = (Button) findViewById(R.id.btnDiv);
Mul = (Button) findViewById(R.id.btnMul);
Clr = (Button) findViewById(R.id.btnClr);
Ext = (Button) findViewById(R.id.btnExt);
txtN1 = (EditText) findViewById(R.id.txtNum1);
txtN2 = (EditText) findViewById(R.id.txtNum2);
txtAn = (EditText) findViewById(R.id.txtAns);
Add.setOnClickListener(new View.OnClickListener() {
[user=439709]@override[/user]
public void onClick(View arg0) {
if (txtN1.getText().toString().length() < 1
|| txtN2.getText().toString().length() < 1) {
dlgAlert.setMessage("Please enter number in text box!");
dlgAlert.setTitle("Enter Number");
dlgAlert.setPositiveButton("OK",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,
int which) {
}
});
dlgAlert.setCancelable(true);
dlgAlert.create().show();
} else {
a = Double.parseDouble(txtN1.getText().toString());
b = Double.parseDouble(txtN2.getText().toString());
c = a + b;
txtAn.setText("" + c);
}
}
});
Sub.setOnClickListener(new View.OnClickListener() {
[user=439709]@override[/user]
public void onClick(View arg0) {
if (txtN1.getText().toString().length() < 1
|| txtN2.getText().toString().length() < 1) {
dlgAlert.setMessage("Please enter number in text box!");
dlgAlert.setTitle("Enter Number");
dlgAlert.setPositiveButton("OK",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,
int which) {
}
});
dlgAlert.setCancelable(true);
dlgAlert.create().show();
} else {
a = Double.parseDouble(txtN1.getText().toString());
b = Double.parseDouble(txtN2.getText().toString());
c = a - b;
txtAn.setText("" + c);
}
}
});
Mul.setOnClickListener(new View.OnClickListener() {
[user=439709]@override[/user]
public void onClick(View arg0) {
if (txtN1.getText().toString().length() < 1
|| txtN2.getText().toString().length() < 1) {
dlgAlert.setMessage("Please enter number in text box!");
dlgAlert.setTitle("Enter Number");
dlgAlert.setPositiveButton("OK",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,
int which) {
}
});
dlgAlert.setCancelable(true);
dlgAlert.create().show();
} else {
a = Double.parseDouble(txtN1.getText().toString());
b = Double.parseDouble(txtN2.getText().toString());
c = a * b;
txtAn.setText("" + c);
}
}
});
Div.setOnClickListener(new View.OnClickListener() {
[user=439709]@override[/user]
public void onClick(View arg0) {
if (txtN1.getText().toString().length() < 1
|| txtN2.getText().toString().length() < 1) {
dlgAlert.setMessage("Please enter number in text box!");
dlgAlert.setTitle("Enter Number");
dlgAlert.setPositiveButton("OK",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,
int which) {
}
});
dlgAlert.setCancelable(true);
dlgAlert.create().show();
} else if (b == 0) {
dlgAlert.setMessage("Number can not be zero");
dlgAlert.setTitle("Divider Zero!");
dlgAlert.setPositiveButton("OK",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,
int which) {
}
});
dlgAlert.setCancelable(true);
dlgAlert.create().show();
} else {
a = Double.parseDouble(txtN1.getText().toString());
b = Double.parseDouble(txtN2.getText().toString());
c = a/b;
txtAn.setText("" + c);
}
}
});
Clr.setOnClickListener(new View.OnClickListener() {
[user=439709]@override[/user]
public void onClick(View arg0) {
txtN1.setText("");
txtN2.setText("");
txtAn.setText("");
}
});
Ext.setOnClickListener(new View.OnClickListener() {
[user=439709]@override[/user]
public void onClick(View arg0) {
finish();
}
});
}
[user=439709]@override[/user]
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}

@nikwen @frenzyboi
Thank you to both of you from the bottom of my heart.
Really feeling awesome after seeing my first app running and rocking.
Any tips for what to do next?
Once again thank you to both of you!!
Sincere Regards
Bullet

[==)BULLET(==] said:
@nikwen @frenzyboi
Thank you both of you from the bottom of my heart.
Real feeling awesome after seeing my first app running and rocking.
Any tips for what to do next?
Once again thank you to both of you!!
Sincere Regards
Bullet
Click to expand...
Click to collapse
You are welcome.
My tips (because you asked me ):
I have started many projects and finished few of them.
The point is: Make an app you NEED or one you think of "That would be VERY cool".
The ones I have needed have always been the ones I have finished.
Good luck.
(Maybe consider creating a game or build an app that does annoying things automatically which you normally have to do yourself.)

nikwen said:
You are welcome.
My tips (because you asked me ):
I have started many projects and finished few of them.
The point is: Make an app you NEED or one you think of "That would be VERY cool".
The ones I have needed have always been the ones I have finished.
Good luck.
(Maybe consider creating a game or build an app that does annoying things automatically which you normally have to do yourself.)
Click to expand...
Click to collapse
I agree with nikwen. The apps you use will be the apps you finish. My advice to you would be to start your calculator over. Try to do it from start to finish and add features or improve on ones you currently have. For instance, add a feature that logs your input and calculation similar to the calculators that print on what they are doing on paper. Once you get the basics down, then you should move on to something more advanced.
Learn and love your logcats. It will help you so much in the debug process.

Related

Hi all, I'm fairly new to Java and my overall coding skills are not as advanced as I'd like them to be but I really would appreciate it if someone could help me with this problem.
My first goal is to code an application for Android which measures the acceleration (X, Y, Z directions) and displays the values in a TextView.
There will be other user configurable options like unit conversion or limits with audio warnings etc. later on.
Right now I only have a few lines of code and the application already force closes right after starting.
I am posting my MainActivity.java, my activity_main.xml and the sensoractivity2 Manifest. Please point me in the right direction!
MainActivity.java:
Code:
package com.example.sensoractivity2;
import android.app.Activity;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.widget.TextView;
public class MainActivity extends Activity implements SensorEventListener{
private SensorManager sensorManager;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
sensorManager=(SensorManager) getSystemService(SENSOR_SERVICE);
sensorManager.registerListener(this, sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER), SensorManager.SENSOR_DELAY_NORMAL);
}
public void onSensorChanged(SensorEvent event) {
float x, y, z = 0;
if (event.sensor.getType()==Sensor.TYPE_ACCELEROMETER) {
x=event.values[0];
y=event.values[1];
z=event.values[2];
TextView tx = (TextView) findViewById(R.id.textView1);
tx.setText((int) x);
TextView ty = (TextView) findViewById(R.id.textView2);
ty.setText((int) y);
TextView tz = (TextView) findViewById(R.id.textView3);
tz.setText((int) z);
}
}
[user=439709]@override[/user]
public void onAccuracyChanged(Sensor arg0, int arg1) {
// TODO Auto-generated method stub
}
}
activity_main.xml
Code:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<TextView
android:id="@+id/textView1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="X-Wert" />
<TextView
android:id="@+id/textView2"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="Y-Wert" />
<TextView
android:id="@+id/textView3"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="Z-Wert" />
</LinearLayout>
sensoractivity2 Manifest:
Code:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.sensoractivity2"
android:versionCode="1"
android:versionName="1.0">
<uses-sdk
android:minSdkVersion="8"/>
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme">
<activity android:name="com.example.sensoractivity2.MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN"/>
<category android:name="android.intent.category.LAUNCHER"/>
</intent-filter>
</activity>
</application>
</manifest>

First thing I see is that you are not setting your view in your activity classes "oncreate" method. Can you post your logcat output when the app force closes? That will help the most.

Could you please post a logcat?
Just the lines of your app. Get it using the logcat view in Eclipse.

Look at the bold for changes that will help you. When you are working with view objects, you shouldn't create the object in a listener or something that is called over and over. You will be creating a memory leak.
Code:
package com.example.sensoractivity2;
import android.app.Activity;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.widget.TextView;
public class MainActivity extends Activity implements SensorEventListener{
private SensorManager sensorManager;
[B]TextView tx = null;
TextView ty = null;
TextView tz = null;[/B]
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
sensorManager=(SensorManager) getSystemService(SENSOR_SERVICE);
[B] setContentView(R.layout.activity_main);[/B]
sensorManager.registerListener(this, sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER), SensorManager.SENSOR_DELAY_NORMAL);
[B]tx = (TextView) findViewById(R.id.textView1);
ty = (TextView) findViewById(R.id.textView2);
tz = (TextView) findViewById(R.id.textView3);[/B]
}
public void onSensorChanged(SensorEvent event) {
float x, y, z = 0;
if (event.sensor.getType()==Sensor.TYPE_ACCELEROMETER) {
x=event.values[0];
y=event.values[1];
z=event.values[2];
[B]tx.setText((int) x);
ty.setText((int) y);
tz.setText((int) z);[/B]
}
}
[user=439709]@override[/user]
public void onAccuracyChanged(Sensor arg0, int arg1) {
// TODO Auto-generated method stub
}
}

Here is the part of the catlog which I believe to be relevant when the crash occurs:
Code:
04-28 18:34:24.628: E/SurfaceFlinger(36): ro.sf.lcd_density must be defined as a build property
04-28 18:34:25.750: E/Trace(1735): error opening trace file: No such file or directory (2)
04-28 18:34:27.452: I/ARMAssembler(36): generated scanline__00000077:03515104_00009002_00000000 [127 ipp] (149 ins) at [0x40f081f0:0x40f08444] in 34521256 ns
04-28 18:34:29.430: I/Choreographer(1153): Skipped 388 frames! The application may be doing too much work on its main thread.
04-28 18:34:29.462: I/ARMAssembler(36): generated scanline__00000077:03010104_00008002_00000000 [ 89 ipp] (110 ins) at [0x40f08450:0x40f08608] in 17654283 ns
04-28 18:34:30.825: W/ActivityManager(1003): Launch timeout has expired, giving up wake lock!
04-28 18:34:31.673: D/AndroidRuntime(1735): Shutting down VM
04-28 18:34:31.673: W/dalvikvm(1735): threadid=1: thread exiting with uncaught exception (group=0x40a71930)
04-28 18:34:31.737: E/AndroidRuntime(1735): FATAL EXCEPTION: main
04-28 18:34:31.737: E/AndroidRuntime(1735): java.lang.NullPointerException
04-28 18:34:31.737: E/AndroidRuntime(1735): at com.example.sensoractivity2.MainActivity.onSensorChanged(MainActivity.java:27)
04-28 18:34:31.737: E/AndroidRuntime(1735): at android.hardware.SystemSensorManager$ListenerDelegate$1.handleMessage(SystemSensorManager.java:204)
04-28 18:34:31.737: E/AndroidRuntime(1735): at android.os.Handler.dispatchMessage(Handler.java:99)
04-28 18:34:31.737: E/AndroidRuntime(1735): at android.os.Looper.loop(Looper.java:137)
04-28 18:34:31.737: E/AndroidRuntime(1735): at android.app.ActivityThread.main(ActivityThread.java:5041)
04-28 18:34:31.737: E/AndroidRuntime(1735): at java.lang.reflect.Method.invokeNative(Native Method)
04-28 18:34:31.737: E/AndroidRuntime(1735): at java.lang.reflect.Method.invoke(Method.java:511)
04-28 18:34:31.737: E/AndroidRuntime(1735): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
04-28 18:34:31.737: E/AndroidRuntime(1735): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
04-28 18:34:31.737: E/AndroidRuntime(1735): at dalvik.system.NativeStart.main(Native Method)
04-28 18:34:31.813: W/ActivityManager(1003): Force finishing activity com.example.sensoractivity2/.MainActivity
04-28 18:34:31.893: W/WindowManager(1003): Failure taking screenshot for (328x583) to layer 21010
04-28 18:34:32.643: D/dalvikvm(1003): GC_FOR_ALLOC freed 588K, 26% free 7082K/9496K, paused 471ms, total 481ms
Thanks for your hints, zalez! Going to try that now.

The logcat states a nullpointer error. I believe my corrections will fix at least that error.
spelaben said:
Here is the part of the catlog which I believe to be relevant when the crash occurs:
Code:
04-28 18:34:24.628: E/SurfaceFlinger(36): ro.sf.lcd_density must be defined as a build property
04-28 18:34:25.750: E/Trace(1735): error opening trace file: No such file or directory (2)
04-28 18:34:27.452: I/ARMAssembler(36): generated scanline__00000077:03515104_00009002_00000000 [127 ipp] (149 ins) at [0x40f081f0:0x40f08444] in 34521256 ns
04-28 18:34:29.430: I/Choreographer(1153): Skipped 388 frames! The application may be doing too much work on its main thread.
04-28 18:34:29.462: I/ARMAssembler(36): generated scanline__00000077:03010104_00008002_00000000 [ 89 ipp] (110 ins) at [0x40f08450:0x40f08608] in 17654283 ns
04-28 18:34:30.825: W/ActivityManager(1003): Launch timeout has expired, giving up wake lock!
04-28 18:34:31.673: D/AndroidRuntime(1735): Shutting down VM
04-28 18:34:31.673: W/dalvikvm(1735): threadid=1: thread exiting with uncaught exception (group=0x40a71930)
04-28 18:34:31.737: E/AndroidRuntime(1735): FATAL EXCEPTION: main
04-28 18:34:31.737: E/AndroidRuntime(1735): java.lang.NullPointerException
04-28 18:34:31.737: E/AndroidRuntime(1735): at com.example.sensoractivity2.MainActivity.onSensorChanged(MainActivity.java:27)
04-28 18:34:31.737: E/AndroidRuntime(1735): at android.hardware.SystemSensorManager$ListenerDelegate$1.handleMessage(SystemSensorManager.java:204)
04-28 18:34:31.737: E/AndroidRuntime(1735): at android.os.Handler.dispatchMessage(Handler.java:99)
04-28 18:34:31.737: E/AndroidRuntime(1735): at android.os.Looper.loop(Looper.java:137)
04-28 18:34:31.737: E/AndroidRuntime(1735): at android.app.ActivityThread.main(ActivityThread.java:5041)
04-28 18:34:31.737: E/AndroidRuntime(1735): at java.lang.reflect.Method.invokeNative(Native Method)
04-28 18:34:31.737: E/AndroidRuntime(1735): at java.lang.reflect.Method.invoke(Method.java:511)
04-28 18:34:31.737: E/AndroidRuntime(1735): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
04-28 18:34:31.737: E/AndroidRuntime(1735): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
04-28 18:34:31.737: E/AndroidRuntime(1735): at dalvik.system.NativeStart.main(Native Method)
04-28 18:34:31.813: W/ActivityManager(1003): Force finishing activity com.example.sensoractivity2/.MainActivity
04-28 18:34:31.893: W/WindowManager(1003): Failure taking screenshot for (328x583) to layer 21010
04-28 18:34:32.643: D/dalvikvm(1003): GC_FOR_ALLOC freed 588K, 26% free 7082K/9496K, paused 471ms, total 481ms
Thanks for your hints, zalez! Going to try that now.
Click to expand...
Click to collapse

zalez said:
The logcat states a nullpointer error. I believe my corrections will fix at least that error.
Click to expand...
Click to collapse
True, nullpointer errors are fixed. After debugging it again, I'm getting these errors now:
Code:
04-28 19:07:59.466: E/AndroidRuntime(858): FATAL EXCEPTION: main
04-28 19:07:59.466: E/AndroidRuntime(858): android.content.res.Resources$NotFoundException: String resource ID #0x0
04-28 19:07:59.466: E/AndroidRuntime(858): at android.content.res.Resources.getText(Resources.java:230)
04-28 19:07:59.466: E/AndroidRuntime(858): at android.widget.TextView.setText(TextView.java:3769)
04-28 19:07:59.466: E/AndroidRuntime(858): at com.example.sensoractivity2.MainActivity.onSensorChanged(MainActivity.java:33)
04-28 19:07:59.466: E/AndroidRuntime(858): at android.hardware.SystemSensorManager$ListenerDelegate$1.handleMessage(SystemSensorManager.java:204)
04-28 19:07:59.466: E/AndroidRuntime(858): at android.os.Handler.dispatchMessage(Handler.java:99)
04-28 19:07:59.466: E/AndroidRuntime(858): at android.os.Looper.loop(Looper.java:137)
04-28 19:07:59.466: E/AndroidRuntime(858): at android.app.ActivityThread.main(ActivityThread.java:5041)
04-28 19:07:59.466: E/AndroidRuntime(858): at java.lang.reflect.Method.invokeNative(Native Method)
04-28 19:07:59.466: E/AndroidRuntime(858): at java.lang.reflect.Method.invoke(Method.java:511)
04-28 19:07:59.466: E/AndroidRuntime(858): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
04-28 19:07:59.466: E/AndroidRuntime(858): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
04-28 19:07:59.466: E/AndroidRuntime(858): at dalvik.system.NativeStart.main(Native Method)
Any ideas?

spelaben said:
True, nullpointer errors are fixed. After debugging it again, I'm getting these errors now:
Code:
04-28 19:07:59.466: E/AndroidRuntime(858): FATAL EXCEPTION: main
04-28 19:07:59.466: E/AndroidRuntime(858): android.content.res.Resources$NotFoundException: String resource ID #0x0
04-28 19:07:59.466: E/AndroidRuntime(858): at android.content.res.Resources.getText(Resources.java:230)
04-28 19:07:59.466: E/AndroidRuntime(858): at android.widget.TextView.setText(TextView.java:3769)
04-28 19:07:59.466: E/AndroidRuntime(858): at com.example.sensoractivity2.MainActivity.onSensorChanged(MainActivity.java:33)
04-28 19:07:59.466: E/AndroidRuntime(858): at android.hardware.SystemSensorManager$ListenerDelegate$1.handleMessage(SystemSensorManager.java:204)
04-28 19:07:59.466: E/AndroidRuntime(858): at android.os.Handler.dispatchMessage(Handler.java:99)
04-28 19:07:59.466: E/AndroidRuntime(858): at android.os.Looper.loop(Looper.java:137)
04-28 19:07:59.466: E/AndroidRuntime(858): at android.app.ActivityThread.main(ActivityThread.java:5041)
04-28 19:07:59.466: E/AndroidRuntime(858): at java.lang.reflect.Method.invokeNative(Native Method)
04-28 19:07:59.466: E/AndroidRuntime(858): at java.lang.reflect.Method.invoke(Method.java:511)
04-28 19:07:59.466: E/AndroidRuntime(858): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
04-28 19:07:59.466: E/AndroidRuntime(858): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
04-28 19:07:59.466: E/AndroidRuntime(858): at dalvik.system.NativeStart.main(Native Method)
Any ideas?
Click to expand...
Click to collapse
It needs to be
Code:
tx.setText(String.valueOf(x));
ty.setText(String.valueOf(y));
tz.setText(String.valueOf(z));
If you pass an int, the TextView thinks that it is a resource id. That is why you need to convert it to a String first.

I over looked the bold part. When setting text for a Textview, it has to be in string format. There is no implied conversion.
Code:
package com.example.sensoractivity2;
import android.app.Activity;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.widget.TextView;
public class MainActivity extends Activity implements SensorEventListener{
private SensorManager sensorManager;
TextView tx = null;
TextView ty = null;
TextView tz = null;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
sensorManager=(SensorManager) getSystemService(SENSOR_SERVICE);
setContentView(R.layout.activity_main);
sensorManager.registerListener(this, sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER), SensorManager.SENSOR_DELAY_NORMAL);
tx = (TextView) findViewById(R.id.textView1);
ty = (TextView) findViewById(R.id.textView2);
tz = (TextView) findViewById(R.id.textView3);
}
public void onSensorChanged(SensorEvent event) {
float x, y, z = 0;
if (event.sensor.getType()==Sensor.TYPE_ACCELEROMETER) {
x=event.values[0];
y=event.values[1];
z=event.values[2];
tx.setText[B](Integer.toString(x)[/B]);
ty.setText([B]Integer.toString(y)[/B]);
tz.setText([B]Integer.toString(z)[/B]);
}
}
[user=439709]@override[/user]
public void onAccuracyChanged(Sensor arg0, int arg1) {
// TODO Auto-generated method stub
}
}

nikwen said:
It needs to be
Code:
tx.setText(String.valueOf(x));
ty.setText(String.valueOf(y));
tz.setText(String.valueOf(z));
If you pass an int, the TextView thinks that it is a resource id. That is why you need to convert it to a String first.
Click to expand...
Click to collapse
Yes! That did the trick! Now my next problem is that I only see one value instead of three, from there on I will try to move on by myself.

Sorry, I'm not sure if this is relevant, but you aren't overriding your onCreate method? Could that have anything to do with it?

MaartenXDA said:
Sorry, I'm not sure if this is relevant, but you aren't overriding your onCreate method? Could that have anything to do with it?
Click to expand...
Click to collapse
He does:
public void onCreate(Bundle savedInstanceState) {
Click to expand...
Click to collapse
He just did not wrote the @override annotation before that. As far as i know, you do not have to use it.
EDIT: Yep, it does not matter. See this: http://stackoverflow.com/questions/94361/when-do-you-use-javas-override-annotation-and-why
It says that it is just for ensuring that you are overriding the right method and for making the code easier to read.

Hi all, I am a bit further with my project since I found some time to work on it again.
//edit, force closes on starting fixed!
Here is what it is supposed to be doing: It reads the x, y and z values for acceleration from the LINEAR_ACCELERATION sensor. If a certain value is exceeded a timer will be started. If the amount of seconds the timer counts is higher than a defined threshold, it will play the default notifcation sound.
If the value from the sensor is below the threshold, it will stop the timer. The whole timer thing isn't working, the notification is played as soon as the normal acceleration threshold is passed and the time is ignored.
Please review my code below and tell me what I'm not seeing here, note that I'm still a noob.
Also I'm interested in a method to capture the maximum values read from the sensor and put it in a textview, can you help me?
AccelMeter.java:
Code:
package com.example.accelmeter;
import android.app.Activity;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.media.Ringtone;
import android.media.RingtoneManager;
import android.net.Uri;
import android.os.Bundle;
import android.os.SystemClock;
import android.view.View;
import android.widget.Button;
import android.widget.Chronometer;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
public class AccelMeter extends Activity implements SensorEventListener {
private SensorManager sensorManager;
// Objekte deklarieren
TextView xC;
TextView yC;
TextView zC;
Chronometer chrono;
/* accThreshold = Schwellenwert in m/s² für die Beschleunigung
* accInterval = Zeitraum in Sekunden, über den der Wert für die Beschleunigung überwacht wird
*/
private float accThreshold = 50;
private float accInterval = 0;
[user=439709]@override[/user]
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_accel_meter);
// Achsen Objekte erstellen
xC=(TextView)findViewById(R.id.xCoordinate);
yC=(TextView)findViewById(R.id.yCoordinate);
zC=(TextView)findViewById(R.id.zCoordinate);
/* Sensor.TYPE_LINEAR_ACCELERATION = Beschleunigung auf jeder Achse ohne Gravitation in m/s²
* SENSOR_DELAY_FASTEST = schnellster Modus für Messung. Alternativen z.B. _GAME, _NORMAL oder _UI
*/
sensorManager=(SensorManager)getSystemService(SENSOR_SERVICE);
sensorManager.registerListener(this,
sensorManager.getDefaultSensor(Sensor.TYPE_LINEAR_ACCELERATION),
SensorManager.SENSOR_DELAY_NORMAL);
// Schwellenwert festlegen und mit einer Toast-Benachrichtigung bestätigen, Fehlerbehandlung wenn kein Wert eingegeben wurde
Button setThreshold = (Button)findViewById(R.id.setThreshold);
setThreshold.setOnClickListener(new Button.OnClickListener() {
public void onClick(View v) {
try {
EditText et = (EditText)findViewById(R.id.threshold);
accThreshold = Float.valueOf(et.getText().toString());
Toast.makeText(getApplicationContext(), "Neuer Schwellenwert festgelegt!", Toast.LENGTH_SHORT).show();
}
catch (Exception e) {
Toast.makeText(getApplicationContext(), "Es wurde noch kein Wert eingegeben!", Toast.LENGTH_SHORT).show();
}
}
});
// Intervall festlegen und mit einer Toast-Benachrichtigung bestätigen, Fehlerbehandlung wenn kein Wert eingegeben wurde
Button setInterval = (Button)findViewById(R.id.setInterval);
setInterval.setOnClickListener(new Button.OnClickListener() {
public void onClick(View v) {
try {
EditText et = (EditText)findViewById(R.id.editInterval);
accInterval = Float.valueOf(et.getText().toString());
Toast.makeText(getApplicationContext(), "Neues Intervall festgelegt!", Toast.LENGTH_SHORT).show();
}
catch (Exception e) {
Toast.makeText(getApplicationContext(), "Es wurde noch kein Wert eingegeben!", Toast.LENGTH_SHORT).show();
}
}
});
// Programm beenden
Button exit = (Button)findViewById(R.id.exit);
exit.setOnClickListener(new Button.OnClickListener() {
public void onClick(View v) {
finish();
System.exit(0);
}
});
}
public void onSensorChanged(SensorEvent event){
// Sensor Typ überprüfen
if(event.sensor.getType()==Sensor.TYPE_LINEAR_ACCELERATION){
// Richtungen verknüpfen
float x=event.values[0];
float y=event.values[1];
float z=event.values[2];
// Gerundete Ergebnisse mit vier Nachkommastellen ausgeben
xC.setText("X: "+(Math.abs(Math.round(x * 1000) / 1000.0)));
yC.setText("Y: "+(Math.abs(Math.round(y * 1000) / 1000.0)));
zC.setText("Z: "+(Math.abs(Math.round(z * 1000) / 1000.0)));
// Wenn Beschleunigung über Schwellenwert liegt, starte Timer. Wenn Timer das festgelete Intervall überschreitet, spiele Benachrichtigungston
if (x + y + z > accThreshold)
{
chrono = new Chronometer(this);
chrono.setBase(SystemClock.elapsedRealtime());
chrono.start();
long seconds = ((chrono.getBase()-SystemClock.elapsedRealtime()/1000%60));
if (seconds >= accInterval)
{
Uri notification = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
Ringtone r = RingtoneManager.getRingtone(getApplicationContext(), notification);
r.play();
}
else
{
chrono.stop();
}
}
}
}
[user=439709]@override[/user]
public void onAccuracyChanged(Sensor sensor, int accuracy) {
// TODO Auto-generated method stub
}
}
activity_accel_meter.xml:
Code:
<?xml version="1.0" encoding="utf-8"?>
<TableLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="fill_parent"
android:layout_height="wrap_content" >
<TableRow tools:ignore="ExtraText" >
<TextView
android:id="@+id/xCoordinate"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="X Koordinate: "
android:textAppearance="?android:attr/textAppearanceLarge"
tools:ignore="HardcodedText" />
/>
</TableRow>
<TableRow>
<TextView
android:id="@+id/yCoordinate"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Y Koordinate: "
android:textAppearance="?android:attr/textAppearanceLarge"
tools:ignore="HardcodedText" />
/>
</TableRow>
<TableRow>
<TextView
android:id="@+id/zCoordinate"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Z Koordinate: "
android:textAppearance="?android:attr/textAppearanceLarge"
tools:ignore="HardcodedText" />
/>
</TableRow>
<EditText
android:id="@+id/threshold"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ems="10"
android:hint="Schwellenwert (float)"
android:inputType="numberDecimal"
tools:ignore="HardcodedText" />
<Button
android:id="@+id/setThreshold"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Schwellenwert festlegen"
tools:ignore="HardcodedText" />
<EditText
android:id="@+id/editInterval"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ems="10"
android:hint="Zeit in Sekunden"
android:inputType="number"
tools:ignore="HardcodedText" >
<requestFocus />
</EditText>
<Button
android:id="@+id/setInterval"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Zeitraum für Überwachung festlegen"
tools:ignore="HardcodedText" />
<Button
android:id="@+id/exit"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Beenden"
tools:ignore="HardcodedText" />
</TableLayout>

Yay German code (live there, too) xD Initialise your seconds in your onCreate, it's much nicer and probably the problem. A method gets the highest value the sensor measured would be a simple
Code:
double savedVal=0; //or any other type
private void updateMaxVal(){
double currentVal =// get the value from the specific sensor
if(savedVal<currentVal) {
savedVal = currentVal;
// maybe save the time as well
}
You'd have to put that method in the onsensorchanged so it will be called often. Then update your text View with the new saved value

SimplicityApks said:
Yay German code (live there, too) xD Initialise your seconds in your onCreate, it's much nicer and probably the problem. A method gets the highest value the sensor measured would be a simple
Code:
double savedVal=0; //or any other type
private void updateMaxVal(){
double currentVal =// get the value from the specific sensor
if(savedVal<currentVal) {
savedVal = currentVal;
// maybe save the time as well
}
You'd have to put that method in the onsensorchanged so it will be called often. Then update your text View with the new saved value
Click to expand...
Click to collapse
Hey fellow German!
If I initialise the seconds variable in the onCreate part it says that the variable is not being used (yellow marking) and in the code below I get an error obviously stating that the variable is unknown. ^^
I have three different values, how can I link the x, y and z variables in the method and how can I make sure the variables are known inside of the method? (Same problem as above)

Since I don't know how to do it with a method I just wrote the following code in my onsensorchanged part, the problem is that the max value textviews always show the same as the current value textviews:
float savedValX = 0;
float savedValY = 0;
float savedValZ = 0;
float currentValX = event.values[0];
float currentValY = event.values[1];
float currentValZ = event.values[2];
if (savedValX < currentValX) {
savedValX = currentValX;
xM.setText("X max: "+(Math.abs(Math.round(currentValX * 1000) / 1000.0)));
}
if (savedValY < currentValY) {
savedValY = currentValY;
yM.setText("Y max: "+(Math.abs(Math.round(currentValY * 1000) / 1000.0)));
}
if (savedValZ < currentValZ) {
savedValZ = currentValZ;
zM.setText("Z max: "+(Math.abs(Math.round(currentValZ * 1000) / 1000.0)));
}
Also I still have the problem that my seconds interval is being ignored.
//edit, fixed it! Now I only need the max value method.

OK so I now understand what you are trying to do with your Chronometer, the problem is that you reinitialize it every time the onSensorChanged is called so if you then ask for the seconds it has just started. To fix this, you could set an onChronometerTickListener and set your textViews in that method. To avoid recreating the Chrono use
Code:
if(chrono==null){
chrono = new Chronometer();
chrono.start();
}
If u don't want the tick listener or it doesn't work ( haven't used it yet) you can put your if(seconds<...)in the else {}of above method. But remember that the onSensorChanged is called EVERYTIME the sensor registers a change, this might be very often or just sometimes, so there is no guarantee that the text views will be updated if the else clause in that method is used
PS forget about the initializing of the seconds, I don't know what I was thinking yesterday, but I guess it was too late ...
/*edit:
What I meant with
Code:
double savedVal=0; //or any other type
private void updateMaxVal(){
is that you save your value in your class ("globally"), so that it is accessible to the whole class.
and to do it nicely you can do it like this:
Code:
float savedValX = 0;
float savedValY = 0;
float savedValZ = 0;
boolean change = false;
private void updateMaxVals(SensorEvent event){ // call this method in your onSensorChanged
change = false;
savedValX = getMax(event.values[0], savedValX);
if(change){
xM.setText("X max: "+(Math.abs(Math.round(savedValX * 1000) / 1000.0)));
}
savedValY = getMax(event.values[1], savedValY);
if(change){
yM.setText("Y max: "+(Math.abs(Math.round(savedValY * 1000) / 1000.0)));
}
savedValZ = getMax(event.values[2], savedValZ);
if(change){
yM.setText("Z max: "+(Math.abs(Math.round(savedValZ * 1000) / 1000.0)));
}
}
private float getMax(float currentVal, float savedVal){
if(currentVal > savedVal){
change = true;
return currentVal;
}else{
change = false;
return savedVal;
}
}

I'm creating a new FragmentPreference and then I want add a OnClickListener to an Preference:
My PreferenceFragment-Class:
Code:
public class PreferencesFragment extends PreferenceFragment {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
addPreferencesFromResource(R.xml.settings);
}
}
And my FragmentActivity:
Code:
public class SettingsActivity extends PreferenceActivity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
PreferencesFragment frag = new PreferencesFragment();
getFragmentManager().beginTransaction().replace(android.R.id.content, frag).commit();
Preference deleteLocalDataPref = frag.findPreference("deleteLocalData");
deleteLocalDataPref.setOnPreferenceClickListener(Pref_OnClickhandler);
}
OnPreferenceClickListener Pref_OnClickhandler = new OnPreferenceClickListener() {
@Override
public boolean onPreferenceClick(Preference arg0) {
new DeleteSettings().execute();
return false;
}
};
}
And the error:
02-10 08:06:10.598: E/AndroidRuntime(1836): FATAL EXCEPTION: main
02-10 08:06:10.598: E/AndroidRuntime(1836): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.test/com.test.SettingsActivity}: java.lang.NullPointerException
02-10 08:06:10.598: E/AndroidRuntime(1836): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
02-10 08:06:10.598: E/AndroidRuntime(1836): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
02-10 08:06:10.598: E/AndroidRuntime(1836): at android.app.ActivityThread.access$600(ActivityThread.java:141)
02-10 08:06:10.598: E/AndroidRuntime(1836): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
02-10 08:06:10.598: E/AndroidRuntime(1836): at android.os.Handler.dispatchMessage(Handler.java:99)
02-10 08:06:10.598: E/AndroidRuntime(1836): at android.os.Looper.loop(Looper.java:137)
02-10 08:06:10.598: E/AndroidRuntime(1836): at android.app.ActivityThread.main(ActivityThread.java:5039)
02-10 08:06:10.598: E/AndroidRuntime(1836): at java.lang.reflect.Method.invokeNative(Native Method)
02-10 08:06:10.598: E/AndroidRuntime(1836): at java.lang.reflect.Method.invoke(Method.java:511)
02-10 08:06:10.598: E/AndroidRuntime(1836): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
02-10 08:06:10.598: E/AndroidRuntime(1836): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
02-10 08:06:10.598: E/AndroidRuntime(1836): at dalvik.system.NativeStart.main(Native Method)
02-10 08:06:10.598: E/AndroidRuntime(1836): Caused by: java.lang.NullPointerException
02-10 08:06:10.598: E/AndroidRuntime(1836): at com.test.SettingsActivity.onCreate(SettingsActivity.java:44)
02-10 08:06:10.598: E/AndroidRuntime(1836): at android.app.Activity.performCreate(Activity.java:5104)
02-10 08:06:10.598: E/AndroidRuntime(1836): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
02-10 08:06:10.598: E/AndroidRuntime(1836): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
02-10 08:06:10.598: E/AndroidRuntime(1836): ... 11 more
Click to expand...
Click to collapse
Why I get a NullPointerException? The Preference does exist...
Code:
<Preference
android:key="deleteLocalData"
android:summary="@string/pref_delete_local_data_summary"
android:title="@string/pref_delete_local_data" />

What happens when you comment the line you think is offending? And which line are you commenting?
Please give a thanks if you think this post helped you!
Sent from my Nexus 4 using XDA Premium 4 Mobile App .

When I comment the lines
Code:
Preference deleteLocalDataPref = frag.findPreference("deleteLocalData");
deleteLocalDataPref.setOnPreferenceClickListener(Pref_OnClickhandler);
my preferences are shown correctly.

OK, I changed some parts. This is what works for me:
Code:
import android.app.Activity;
import android.os.Bundle;
import android.preference.Preference;
import android.preference.PreferenceFragment;
public class SettingsActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.settings);
PreferenceFragment preferenceFragment = (PreferenceFragment) getFragmentManager().findFragmentById(R.id.pref_frag_id);
Preference deleteLocalDataPref = preferenceFragment.findPreference("deleteLocalData");
deleteLocalDataPref.setOnPreferenceClickListener(Pref_OnClickhandler);
}
Preference.OnPreferenceClickListener Pref_OnClickhandler = new Preference.OnPreferenceClickListener() {
@Override
public boolean onPreferenceClick(Preference arg0) {
new DeleteSettings().execute();
return false;
}
};
}
/res/layout/settings.xml:
Code:
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<fragment
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:name="com.example.app.PreferencesFragment"
android:id="@+id/pref_frag_id"/>
</FrameLayout>
(Replace the package name.)
/res/xml/settings.xml:
Code:
<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
<Preference
android:key="deleteLocalData"
android:summary="@string/pref_delete_local_data_summary"
android:title="@string/pref_delete_local_data" />
</PreferenceScreen>
I changed the way the Fragment is added. If you need to do it dynamically, have a look at a tutorial again and follow it closely.
You don't need to use a PreferenceActivity. The PreferenceFragment kind of replaced it. It is more flexible (it can be added to any kind of Activity) and the PreferenceActivity should only be used for apps which are supposed to work on Android versions below 3.0.

when I try to use ShowcaseView I get error
Code:
@override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
final ImageButton saveButton = (ImageButton) view.findViewById(R.id.button_Save);
ViewTarget viewTarget = new ViewTarget(saveButton);
showcaseView = new ShowcaseView.Builder(getActivity())
.setTarget(viewTarget)
.setContentTitle("Reset Button")
.setContentText("This will erase all the data in the table except the line that in progress")
.build();
}
when I tried to do the same thing in my fragmentactivity and didn't work, but when I did the same thing but took a view that declared in the fragmentactivity and not in the fragment it worked.
Logcat:
Code:
FATAL EXCEPTION: main
java.lang.IllegalArgumentException: width and height must be > 0
at android.graphics.Bitmap.createBitmap(Bitmap.java:724)
at android.graphics.Bitmap.createBitmap(Bitmap.java:703)
at android.graphics.Bitmap.createBitmap(Bitmap.java:670)
at com.github.amlcurran.showcaseview.ShowcaseView.updateBitmap(ShowcaseView.java:169)
at com.github.amlcurran.showcaseview.ShowcaseView.onGlobalLayout(ShowcaseView.java:343)
at android.view.ViewTreeObserver.dispatchOnGlobalLayout(ViewTreeObserver.java:839)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2050)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1249)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6364)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:791)
at android.view.Choreographer.doCallbacks(Choreographer.java:591)
at android.view.Choreographer.doFrame(Choreographer.java:561)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:777)
at android.os.Handler.handleCallback(Handler.java:730)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:176)
at android.app.ActivityThread.main(ActivityThread.java:5419)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1046)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:862)
at dalvik.system.NativeStart.main(Native Method)
I understand what the error said but how can I fix it?

I am getting a NullPointerException after the build but once my phone tries to launch the app. I do not understand where the problem is. Im just learning to code and this app is simply supposed to make a toast pop up Long if the checkbox is clicked and short if it isnt.
Code:
package universaltruth.toastee;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.Toast;
public class MainActivity extends ActionBarActivity {
public CheckBox longToast = (CheckBox) findViewById(R.id.checkbox);
public EditText editText = (EditText) findViewById(R.id.toastText);
public int toastLength = 0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
addListenerOnlongToast();
}
public void addListenerOnlongToast(){
longToast.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View view) {
if(((CheckBox) view).isChecked()){
toastLength = '1';
}
}
});
}
public void toastMessage(View view){
String message = editText.getText().toString();
Toast.makeText(getApplicationContext(),message, (toastLength == 0) ? Toast.LENGTH_SHORT : Toast.LENGTH_LONG).show();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
LogCat:
02-08 12:48:34.718 6684-6684/universaltruth.toastee D/AndroidRuntime﹕ Shutting down VM
02-08 12:48:34.718 6684-6684/universaltruth.toastee W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0x4191bda0)
02-08 12:48:34.718 6684-6684/universaltruth.toastee E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: universaltruth.toastee, PID: 6684
java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{universaltruth.toastee/universaltruth.toastee.MainActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2408)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2599)
at android.app.ActivityThread.access$900(ActivityThread.java:174)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1321)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:146)
at android.app.ActivityThread.main(ActivityThread.java:5748)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1291)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1107)
at de.robv.android.xposed.XposedBridge.main(XposedBridge.java:132)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at android.app.Activity.findViewById(Activity.java:2014)
at universaltruth.toastee.MainActivity.<init>(MainActivity.java:19)
at java.lang.Class.newInstanceImpl(Native Method)
at java.lang.Class.newInstance(Class.java:1208)
at android.app.Instrumentation.newActivity(Instrumentation.java:1067)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2399)
************at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2599)
************at android.app.ActivityThread.access$900(ActivityThread.java:174)
************at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1321)
************at android.os.Handler.dispatchMessage(Handler.java:102)
************at android.os.Looper.loop(Looper.java:146)
************at android.app.ActivityThread.main(ActivityThread.java:5748)
************at java.lang.reflect.Method.invokeNative(Native Method)
************at java.lang.reflect.Method.invoke(Method.java:515)
************at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1291)
************at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1107)
************at de.robv.android.xposed.XposedBridge.main(XposedBridge.java:132)
************at dalvik.system.NativeStart.main(Native Method)
02-08 13:00:50.672 9121-9121/universaltruth.toastee I/SELinux﹕ Function: selinux_android_load_priority , priority [3] , priority version is VE=SEPF_SM-N910F_4.4.4_A024
02-08 13:00:50.672 9121-9121/universaltruth.toastee E/SELinux﹕ [DEBUG] get_category: variable seinfocat: default sensitivity: NULL, cateogry: NULL
02-08 13:00:50.672 9121-9121/universaltruth.toastee E/dalvikvm﹕ >>>>> Normal User
02-08 13:00:50.672 9121-9121/universaltruth.toastee E/dalvikvm﹕ >>>>> universaltruth.toastee [ userId:0 | appId:10384 ]
02-08 13:00:50.682 9121-9121/universaltruth.toastee E/SELinux﹕ [DEBUG] get_category: variable seinfocat: default sensitivity: NULL, cateogry: NULL
02-08 13:00:50.682 9121-9121/universaltruth.toastee D/dalvikvm﹕ Late-enabling CheckJNI
02-08 13:00:50.682 9121-9121/universaltruth.toastee I/libpersona﹕ KNOX_SDCARD checking this for 10384
02-08 13:00:50.682 9121-9121/universaltruth.toastee I/libpersona﹕ KNOX_SDCARD not a persona
02-08 13:00:50.752 9121-9121/universaltruth.toastee D/TimaKeyStoreProvider﹕ in addTimaSignatureService
02-08 13:00:50.762 9121-9121/universaltruth.toastee D/TimaKeyStoreProvider﹕ Cannot add TimaSignature Service, License check Failed
02-08 13:00:50.762 9121-9121/universaltruth.toastee D/ActivityThread﹕ Added TimaKesytore provider
02-08 13:00:50.922 9121-9121/universaltruth.toastee D/AndroidRuntime﹕ Shutting down VM
02-08 13:00:50.922 9121-9121/universaltruth.toastee W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0x4191bda0)
02-08 13:00:50.922 9121-9121/universaltruth.toastee E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: universaltruth.toastee, PID: 9121
java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{universaltruth.toastee/universaltruth.toastee.MainActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2408)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2599)
at android.app.ActivityThread.access$900(ActivityThread.java:174)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1321)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:146)
at android.app.ActivityThread.main(ActivityThread.java:5748)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1291)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1107)
at de.robv.android.xposed.XposedBridge.main(XposedBridge.java:132)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at android.app.Activity.findViewById(Activity.java:2014)
at universaltruth.toastee.MainActivity.<init>(MainActivity.java:16)
at java.lang.Class.newInstanceImpl(Native Method)
at java.lang.Class.newInstance(Class.java:1208)
at android.app.Instrumentation.newActivity(Instrumentation.java:1067)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2399)
************at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2599)
************at android.app.ActivityThread.access$900(ActivityThread.java:174)
************at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1321)
************at android.os.Handler.dispatchMessage(Handler.java:102)
************at android.os.Looper.loop(Looper.java:146)
************at android.app.ActivityThread.main(ActivityThread.java:5748)
************at java.lang.reflect.Method.invokeNative(Native Method)
************at java.lang.reflect.Method.invoke(Method.java:515)
************at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1291)
************at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1107)
************at de.robv.android.xposed.XposedBridge.main(XposedBridge.java:132)
************at dalvik.system.NativeStart.main(Native Method)
02-08 13:00:55.232 9121-9121/universaltruth.toastee I/Process﹕ Sending signal. PID: 9121 SIG: 9
Forgive me if I am not posting this correctly. This is my first time. I am open to any and all feedback. Thank you.

Your problem is that you initialize the longToast checkbox outside of a method. But findViewById only returns a result if called after a call to setContentView(...), which is done in onCreate. So: put your initialization code into onCreate, after setContentView and it will work fine
--------------------
Phone: Nexus 4
OS: rooted Lollipop LRX21T
Bootloader: unlocked
Recovery: TWRP 2.8.2.0

Masrepus said:
Your problem is that you initialize the longToast checkbox outside of a method. But findViewById only returns a result if called after a call to setContentView(...), which is done in onCreate. So: put your initialization code into onCreate, after setContentView and it will work fine
Click to expand...
Click to collapse
Hey Masrepus,
Thanks a bunch for answering me.
I have moved the initializations to the on create after the setContentView. I am still getting the null pointer exception. Do you have any further advice?

UniversalTruth said:
Hey Masrepus,
Thanks a bunch for answering me.
I have moved the initializations to the on create after the setContentView. I am still getting the null pointer exception. Do you have any further advice?
Click to expand...
Click to collapse
Can you edit the first post with the new code (and new logcat)?

Yes, grab a new log and post it on pastebin
Then link the log from here

Hello,
I am trying to build an Android Studio project based on a simple example from the web with VideoView. Everything seems OK, the project builds successfully but both in the emulator and on my device it gives an error: "Unfortunately [myapp] has stopped". This is getting really frustrating, I've searched the Internet for similar errors but didn't find any solution to my case. I think the code is ok but there is something with the settings because I imported the project from a web example:
itcuties[dot]com/android/play-video/
Anyway, the code is:
........SelectActivity.java........
Code:
package com.itcuties.android.videoplayer;
import android.app.Activity;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
/**
* Select video source activity.
*
* @see ITCuties
*/
public class SelectActivity extends Activity implements OnClickListener {
private Button playFromUrlButton;
private Button playOnYouTubeButton;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_select);
playFromUrlButton = (Button) findViewById(R.id.buttonURL);
playOnYouTubeButton = (Button) findViewById(R.id.buttonOnYouTube);
// Set onClickListener
playFromUrlButton.setOnClickListener(this);
playOnYouTubeButton.setOnClickListener(this);
}
@Override
public void onClick(View v) {
// Check which button was clicked
if (playFromUrlButton.isPressed()) {
Intent i = new Intent(SelectActivity.this, URLVideoActivity.class);
SelectActivity.this.startActivity(i);
} else if (playOnYouTubeButton.isPressed()) {
Intent i = new Intent(Intent.ACTION_VIEW);
i.setData(Uri.parse([B][I]"<Youtbe page>[/I][/B]"));
SelectActivity.this.startActivity(i);
}
}
}
........URLVideoActivity.java........
Code:
package com.itcuties.android.videoplayer;
import android.app.Activity;
import android.os.Bundle;
import android.widget.VideoView;
/**
* Play Video from URL
*
* @see ITCuties
*/
public class URLVideoActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.url_activity_video);
VideoView video = (VideoView)findViewById(R.id.videoView);
video.setVideoPath("[I][B]<Address to mp4 file>[/B][/I]");
video.start();
}
}
........AndroidManifest.xml........
Code:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="[I][B]<schemas android link>[/B][/I]"
package="com.itcuties.android.videoplayer"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="8" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name" >
<activity
android:name="com.itcuties.android.videoplayer.URLVideoActivity"
android:configChanges="orientation|keyboardHidden|screenSize"
android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
</intent-filter>
</activity>
<activity
android:name="com.itcuties.android.videoplayer.SelectActivity"
android:configChanges="orientation|keyboardHidden|screenSize"
android:label="@string/title_activity_select">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
The error from emulator console:
Code:
07-02 17:41:19.689 2524-2524/? D/dalvikvm﹕ Not late-enabling CheckJNI (already on)
07-02 17:41:20.270 2524-2524/? I/dalvikvm﹕ Turning on JNI app bug workarounds for target SDK version 8...
07-02 17:41:20.479 2524-2524/? E/Trace﹕ error opening trace file: No such file or directory (2)
07-02 17:41:20.939 2524-2524/com.itcuties.android.videoplayer D/AndroidRuntime﹕ Shutting down VM
07-02 17:41:20.939 2524-2524/com.itcuties.android.videoplayer W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0x40a71930)
07-02 17:41:20.959 2524-2524/com.itcuties.android.videoplayer E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.itcuties.android.videoplayer/com.itcuties.android.videoplayer.SelectActivity}: java.lang.ClassNotFoundException: Didn't find class "com.itcuties.android.videoplayer.SelectActivity" on path: /data/app/com.itcuties.android.videoplayer-2.apk
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2106)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
at android.app.ActivityThread.access$600(ActivityThread.java:141)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5041)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.ClassNotFoundException: Didn't find class "com.itcuties.android.videoplayer.SelectActivity" on path: /data/app/com.itcuties.android.videoplayer-2.apk
at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:65)
at java.lang.ClassLoader.loadClass(ClassLoader.java:501)
at java.lang.ClassLoader.loadClass(ClassLoader.java:461)
at android.app.Instrumentation.newActivity(Instrumentation.java:1054)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2097)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
at android.app.ActivityThread.access$600(ActivityThread.java:141)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5041)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
at dalvik.system.NativeStart.main(Native Method)
Anybody? Thanks in advance.
Adi.

Classnotfound exception
You didn't post the SelectActivity.java for this.
Did you create this ?
Please share the content for the SelectActivity.java class.

Change the below codes :
Code:
if (playFromUrlButton.isPressed()) {
Intent i = new Intent(SelectActivity.this, URLVideoActivity.class);
SelectActivity.this.startActivity(i);
} else if (playOnYouTubeButton.isPressed()) {
Intent i = new Intent(Intent.ACTION_VIEW);
i.setData(Uri.parse([B][I]"<Youtbe page>[/I][/B]"));
SelectActivity.this.startActivity(i);
}
To this:
Code:
if (playFromUrlButton.isPressed()) {
Intent i = new Intent(SelectActivity.this, URLVideoActivity.class);
startActivity(i);
} else if (playOnYouTubeButton.isPressed()) {
Intent i = new Intent(Intent.ACTION_VIEW);
i.setData(Uri.parse([B][I]"<Youtbe page>[/I][/B]"));
startActivity(i);
}

satyampv,
I guess I have? I don't understand.
Vivek_Neel:
Thanks for reply but the error sill persists

haloperidollly said:
satyampv,
I guess I have? I don't understand.
Vivek_Neel:
Thanks for reply but the error sill persists
Click to expand...
Click to collapse
Can you try to run this app on your phone and see if it works?

It doesn't work neither on emulator nor on my tablet - same error.