[Q] Android as an external (text) display: Linux/ADB/USB? - Android Software Development

Hi everyone,
I would like to write an application (chain) like that:
MyLinuxApplication->FloatNumber->CallOfALibrary->SendToUsb->AndroidAsUsbDevice->AndroidAppToDisplayThatFloatNumber
All in all I want to send that float number about 30 times per second to Android as a live monitor/display for that value.
Is anyone aware of any other threads/tutorials/similar open source applications to avoid building such a solution from scratch?
I am aware of the iDisplay app. But it is too slow and it is Windows. The rest of our system is Linux and there is no chance to change it. Moreover I do not need any graphical content to be transmitted. Just a float number.
For the "SendToUsb->AndroidAsUsbDevice" part I could think of using ADB. Is there any example out there how to do "ADB->AndroidAppToDisplayThatFloatNumber" with the required speed? Any good ideas for "CallOfALibrary->Adb" otherwise I might end up abusing the adb shell interface.
If ADB does not work: There is an example of how to get data from an USB endpoint to an Android app on developers.android.com. However, does anyone have an example of "FloatNumber->CallOfALibrary->SendToUsb->UsbEndpoint"?
I did usb driver programming for windows about 5 years ago with the DDK and it was not fun. I fear it will be even worse in Linux. Anyone having experience with that?
Thanks for your help,
Simon

Related

Remote PDA Management Software

Hi all,
I joined the forum because I'm looking to design a PC application using Visual Studio 2005 that will connect to most phones and allow you to send/receive SMS, manage contacts, perhaps even use any onboard camera as a webcam.
I'm an experienced programmer, but know little about the architecture on the Andes, which is my testbed.
Basically, all I need to get started on the basics is how to communicate with the device using a serial connection (Not in debug mode though!), or the best way to accomplish this if not bluetooth.
Any/all help appreciated. I'm not looking for code just a procedure to establish a serial link that'll allow me to issue commands to the device whilst its in its usual turned on and usable state, or docked. However if you think it'll help please feel free.
Many thanks in advance!
opennetcf.org has examples and a free library which you can download
Eelco
Many thanks! However from what I can see, I'd need the latest version, which is not free :S Any attempt to install the previous SDK's fail as I'm running VS2005...
Ok, to clarify, I'm looking for a framework for a windows application that will enable me to connect to a smartphone, and control it. From what I can tell from the above site, the Opennetcf libraries are for a device application... I've installed the free version of the libraries and they work find under the emulator, but that's not really what I'm after...

Windows XP Embedded on HTC devices?

Hi folks
Recenty I got the Windows XP Embedded kit, and I was really satisfied and surprised with the performance of the directly built system on an old machine like a P1 @ 200 MHz with 64 MB of RAM, without a hard disk.
The main goal would be to run truly win32 apps on mobile devices, to give better functionality and compatibility.
Yet the builder supports x86 architecture only, but cannot be a big problem to port it to ARM pocessors.
What might be difficult are these things:
-Getting win32 drivers for built-in devices (ex. integrated SDIO/USB WLAN, BT adapter, touchscreen, and sound devices, and apps for them!)
-Saving user data on turning off (Ebmedded systems are designed for a workstation, like a cash register: prebuilt apps, and nothing more comfort ) like WM200x
If anybody has any suggestion are to get a warm welcome
bye
Yet the builder supports x86 architecture only, but cannot be a big problem to port it to ARM pocessors.
Click to expand...
Click to collapse
Are you kidding me?
This would mean reverse engineering and recompiling every binary in the OS.
Do you have any idea how many hours something like that would take?
yup, you're right, but in theory it's possibe. I've seen a running DOS on a Microchip micro-controller, or for example the Atmel STK 1000 is Linux based, also seen an mPlayer app operational on the demo board at the college.
as you see, i'm not an experienced programmer, but i'm not afraid to ask
Yeah, the basic low-level binaries must be recompiled, and once it's ok, it might be usable with regular win32 apps, until you run an old DOS app, wich directly access the hardware.
A few years ago i was able to port Z80 software to 8086, and it wasn't easy.
I don't really know these things, just want to see opinions, possibilities, and suggestions.
exe files are binarys which are instructions directly for the cpu
it's not parsed by the operating system
so compiling the os is not enough every application needs to be recompiled too
The programs you mentioned have source available in one way or another (since DOS is very old there are clones, like freeDOS).
If you have the full source for an app and the right compiler, porting it to another CPU is feasible.
But, this is not the case with embedded XP. Getting the full source is impossible which means most of the system will have to be rewritten from scratch.
Just look at the Wine project to see what it takes, and they "have it easy" - they are just trying to simulate the APIs not change processor architecture. (Lets make it clear - ARM instruction set is very different from x86).
And as Rudegar said it will not let you run any program that has not been specially compiled for ARM CPU.
I know it sounds like we are trying to kill you idea here but its nothing personal, unfortunately it just isn't feasible. We would all like to be able to run desktop apps on our devices, but simply having embedded XP on them would not accomplish that. Also while many old DOS apps can be run using various emulators like pocketDOS, almost all Win32 apps take more resources than our little gadgets can offer.
I am fairly sure though that in 5 -10 years that problem will be fixed.
<_< man hours or not, reveng'ing this will have a bigger impact than just winDOS Mobile devices. Desktops have a use for this, definitely (because the Vista-Only crap is starting to hit the market). Too bad they don't provide assembly in programming classes anymore, obviously because they don't want anyone else to reverse engineer anything and spoil their foisting fun. <_<
In any case, IIRC XP Embedded is missing the install/uninstall engine, so you can't customize it after it's flashed onto the board. This isn't quite a good start - XPLite or 98Lite are better for reverse engineering from scratch (but they're too powerful for mobile devices).
The other alternative is porting ReactOS, which is a reimplementation of W2K. Those guys are "having a lot of fun" getting things to work, tho. <_<
Maybye Windows CE6 yes, but Windows XP Embedded no, because they must run at 686-AT/X platform IMB. Sorry of my English
linux would be a path
with most linux programs you can compile them yourself
using good old
./configure
make
make install
of cause gui programs could have issues displaying correct
on such a small screen
You MIGHT be able to pull it off by installing a minimal (very!) WinMo firmware and then have it autorun Bochs, which is known to be able to run the PC version of XP.. A customised, thinned-down XPe image should run fine under Bochs.
--W5i2

[Q] Some questions about developing

Hi there, i'm new to developing Android Apps, so i have some questions.
1. I know that always have a chance of breaking security on computer world
2. Whats the most secure method to generate a UniqueID? because my app needs to work on china tablets, original tablets, cellphones, hacked phones, etc. I need this for verification of paid things (wait, xda will have a free version ;o)
3. There is any way to encript the program without affecting the performance too much? I'm new to java and comming from C++, so there is any compaction, encrypt, etc? Because if anybody knows the NEW IDA will come with android support.
4. There is any HTML parser on java? Because i need to fetch a html page with httpclient and after i need to parse it to get content... the contect is dynamic (html table with N rows), so i need a parser... or there is any other way?
5. I know how to make a tabed interface, but how is the best way to know the app state? Like it:
App Start -> User Already Logged (Save on SQLite?) ?
Yes = Display app interface and unlock config menu (here is the tabed interface)
No = Display login interface and lock config menu (here is just a relative layout with login bnts)
Thanks in advance.
1: Number one is not a question.
2: Do you mean most secure possible, or most secure practical? Those concerns should be addressed. Most secure would be to have a courier bring the user one-time-pads for every session, but that's not very practical. That said, what is the nature of your ID? Depending on what you are using it for, I would think a few randomly generated bits from some user entered entropy (like touchpad event timing) should suffice.
3: Again, what is the nature of your need for encryption? Do you want to keep it from being decompiled and analysed? If so, you're pretty much out of luck as there is always a way for a dedicated hacker to disassemble the code that does the decryption unless you use some sort of challenge-handshaking algorithm to load the keys at runtime for every session from some secure source but that requires connectivity and user interaction which necessarily complicates the process.
4: The XML parsers available as part of the Android SDK do a pretty good job of parsing HTML if it is clean compliant HTM> See, i.e. the Sax classes:
http://developer.android.com/reference/org/xml/sax/package-summary.html
5: You can use the API included preference classes to save state between sessions:
http://developer.android.com/reference/android/preference/package-summary.html
Note: for general application cryptography information, you still can't beat the venerated Applied Cryptography by Bruce Schneier.
Thanks for the answers.
I just wanna know how the most used programs like rom manager, power amp, titanium backup and whatsapp protect their paid versions, and how they validate it.
Another question that leaves on it is that some programs have a dedicated paid version, and some have just a key that you download and unlock the free version, how they did it? They just check if key is installed assuming that it was downloaded from market?
My uses is just for two reasons:
1.) protect my app as possible from newbie crackers
2.) transmit user information with a secure method to my server. Its important because my app will be used on open networks.
As for UniqueID generating, i just wanna a "unique world global super id" for each user of my app, and it will be installed on cellphones, tablets without phone, tv with android, and all of this.
Also, what to do if html is not well formated?

C++: open file for writing in the LocalStorage

Hi guys, could you tell me how to open file for writing in the phone app LocalStorage for the non-unlocked handset (regular app for store)?
Code below doesn't work
Code:
FILE *tmp;
auto tmpPath = Windows::Storage::ApplicationData::Current->LocalFolder->Path + "\\tmp.txt";
auto tmpErr = _wfopen_s(&tmp, tmpPath->Data(), L"w");
Any suggestions?
Try looking though msdn articles. I found it somewhere in there. But I have forgotten it now.
Sent from Board Express on my Nokia Lumia 1020. Best phone ever!!
Note to noobs: DON'T PM ME WITH QUESTIONS. POST IN THE FORUMS. THAT'S WHAT THEY ARE HERE FOR!
@wcomhelp, please keep your rtfm advices for yourself, OK? I'm not a noob and of course I've searched msdn, google, codeplex, github etc. and so on before posting here. If you don't know how, much better be silent (like others who read this post but have no idea what I'm talking about)
I've tried a few possible methods including ugly "MS-way" with task & lambda syntax (see below) but nothing worked as it should be (code below works if no file exist and fails if file already exist - CreationCollisionOption::ReplaceExisting options is not worked/not implemented/buggy/billgates_knows_only ).
Code:
auto folder = Windows::Storage::ApplicationData::Current->LocalFolder;
Concurrency::task<Windows::Storage::StorageFile^> createFileOp(
folder->CreateFileAsync(CONFIG_FILE_NAME, Windows::Storage::CreationCollisionOption::ReplaceExisting));
createFileOp.then([=](Windows::Storage::StorageFile^ file)
{
return file->OpenAsync(Windows::Storage::FileAccessMode::ReadWrite);
})
.then([=](Windows::Storage::Streams::IRandomAccessStream^ stream)
{
auto outputStream = stream->GetOutputStreamAt(0);
auto dataWriter = ref new Windows::Storage::Streams::DataWriter(outputStream);
// data save code skipped
return dataWriter->StoreAsync();
})
.wait();
BTW, I've used workaround, to save ported C++ app data to the LocalSettings instead of text file (as it was in original code).
"Doesn't work" doesn't give us a lot to go on, troubleshooting-wise. Can you tell us what error you get?
Only thing I see in the code that looks a little weird is that the
Code:
"\\tmp.txt"
part isn't explicitly a wide-character string, but I'd expect string concatenation to take care of that.
Also, out of curiosity, why libc functions instead of Win32? Obviously, the code you're writing here isn't intended for much portability...
@GoodDayToDie, there is no error code at all - standard POSIX functions returns NULL FILE, the ::GetLastError() also return 0.
I'm porting old C-style app to WinRT platform and don't care about portability (but the first post code - just a simplified example, nothing more).
POSIX (libc) functions works pretty well for reading only but not for writing - that's the problem...
As I said before, I resolved my issue by workaround but still curious why the POSIX calls fails for file writing in the app storage.
buuuuuuuuuuuuuuuuh
No need for lambdas
https://paoloseverini.wordpress.com/2014/04/22/async-await-in-c/
You may also want to rethink your strategy
You can't create files at arbitrary locations, so your method is kinda redundant. All the locations you are allowed to create and read files to/from are available through KnowFolders and ApplicationData classes. These return StorageFolders which in turn can create files with CreateFileAsync (used for both creating and opening existing files) and get files with GetFilesAsync ( I recommend against this one though) and similar methods.
@mcosmin222, could you please re-read my posts one more time? I'm not trying to create files at "arbitrary locations"; I wanna create/write simple text file at the app's local storage (which one should be available for reading/writing). And the problem not in the lambdas or task usage (yes, it looks ugly but it works as it supposed to be).
Could you provide a working example instead of words? And I'll be glad to say you "thanks a lot"; can't say now...
sensboston said:
@mcosmin222, could you please re-read my posts one more time? I'm not trying to create files at "arbitrary locations"; I wanna create/write simple text file at the app's local storage (which one should be available for reading/writing). And the main problem not in the task (async execution).
Could you provide a working example instead of words? And I'll be glad to say you "thanks a lot"; can't say now...
Click to expand...
Click to collapse
Sure, just gimmie a few hours till I can get near a compiler that is capable of doing that
Of course, no rush at all, take your time. It's not a showstopper for me now (actually, my workaround with AppSettings is more preferable way - at least for universal app and roaming settings) but the issue still has an "academic interest" and maybe will be useful in the next projects for porting old C/C++ code to WinRT.
sensboston said:
Of course, no rush at all, take your time. It's not a showstopper for me now (actually, my workaround with AppSettings is more preferable way - at least for universal app and roaming settings) but the issue still has an "academic interest" and maybe will be useful in the next projects for porting old C/C++ code to WinRT.
Click to expand...
Click to collapse
hi
in vs 2015
#include <pplawait.h>
Something of the like should work
Code:
WriteSomeFile() __resumable
{
auto local = ApplicationData::Current->LocalFolder;
auto file = __await local->CreateFileAsync("some file", CreationCollisionOption::eek:penIfExists);
__await FileIO::WriteTextAsync(file, "this is some text");
}
However, as of right now, in VS 2015 RC, you have a host of limitations when dealing with this, but I do not believe this will be of any issue to you.
Code:
Cannot use Windows Runtime (WinRT) types in the signature of resumable function and resumable function cannot be a member function in a WinRT class. (This is fixed, but didn't make it in time for RC release)
We may give a wrong diagnostic if return statement appears in resumable function prior to seeing an await expression or yield statement. (Workaround: restructure your code so that the first return happens after yield or await)
Compiling code with resumable functions may result in compilation errors or bad codegen if compiled with /ZI flag (Edit and Continue debugging)
Parameters of a resumable function may not be visible while debugging
Please see this link for additional details
http://blogs.msdn.com/b/vcblog/archive/2015/04/29/more-about-resumable-functions-in-c.aspx
you should also note that this works with native, standard C++ types.
@mcosmin222, looks like unbuffered writing works (i.e. without streams) fine but it still not an answer for my initial question
I'm curious why the standard POSIX libc writing operations are not working on the app's local storage (but reading from files works fine). Actually, it's all about porting old C/C++ code for WinRT; of course for the new app it's not a problem but re-writing old code to FileIO should be a huge pain in the ass. What I did: I've "mechanically" changed all libc formatted outputs from file to string, and use LocalSettings class (actually it's XML file) to store that string (I'm planning also change LocalSettings to RoamingSettings, to provide settings consistency between WP & desktop app).
P.S. <pplawait.h> is not available in my VS 2015 (release pro version) so I've tested by using lambda pattern.
OK, first things first, LIBC != POSIX! The POSIX way to do this would be to call the open() function and get back an int as an "fd" (file descriptor), which is of course not implemented on Windows Phone because Windows Phone is not a POSIX platform (you might find the Windows compatibility functions _open() and _wopen(), but I doubt it). You are attempting to use the standard C library functions, which are portable but implement kind of a lowest common denominator of functionality and are generally slightly slower than native APIs because they go through a portability wrapper.
Second, sorry to be all RTFM on you but you should really Read The Manual (or manpage, or, since this is Windows, the MSDN page)! Libc APIs set errno (include errno.h) and use different error values than Windows system error codes (or HRESULT codes, or NTSTATUS codes, or...). Error reporting in C is a mess. If you were calling CreateFile(), you would check GetLastError(), but since you're calling _wfopen(), you check errno (not a function).
@GoodDayToDie, _wfopen_s returns 0 (i.e. "no error") but tmp pointer receives also 0 (NULL) Could you explain why libc file functions are working for reading (at the app installation & local data folders of course) but not for writing? Any logical ("msdn based") explanation? Or you just... don't know, heh?
sensboston said:
@GoodDayToDie, _wfopen_s returns 0 (i.e. "no error") but tmp pointer receives also 0 (NULL) Could you explain why libc file functions are working for reading (at the app installation & local data folders of course) but not for writing? Any logical ("msdn based") explanation? Or you just... don't know, heh?
Click to expand...
Click to collapse
LIBC functions will most likely work just in debug mode. The moment you try to publish the app it will fail. You can do lots of crazy stuff on your developer device with basic C functions, but if you try publishing, it won't pass the marketplace verification.
Most C APIs are simply not supported, since they do not comply with the sandbox environment of the Windows Runtime.
The code I gave you is tested with VS 2015 RC. You should be able to include <pplawait.h> just fine, if you are targeting toolchains newer than November 2013.
mcosmin222 said:
The moment you try to publish the app it will fail. You can do lots of crazy stuff on your developer device with basic C functions, but if you try publishing, it won't pass the marketplace verification.
Click to expand...
Click to collapse
Hmm... Are you sure or it's just your assumption? My app is still under development but (just for test!) I've made store app package for WP and it passed local store verification I also uploaded package to the store (via browser) and it also passed. I don't have time to create all tiles and fill all fields to complete beta-submission (actually, I don't know how to mark app as beta in the new dashboard) but for me it looks like app don't have any problem and will pass store certification easily. And you may be sure - it uses A LOT of libc calls 'cause originally it was written for Linux (or kind of UX system)
sensboston said:
Hmm... Are you sure or it's just your assumption? My app is still under development but (just for test!) I've made store app package for WP and it passed local store verification I also uploaded package to the store (via browser) and it also passed. I don't have time to create all tiles and fill all fields to complete beta-submission (actually, I don't know how to mark app as beta in the new dashboard) but for me it looks like app don't have any problem and will pass store certification easily. And you may be sure - it uses A LOT of libc calls 'cause originally it was written for Linux (or kind of UX system)
Click to expand...
Click to collapse
Once usage reports get up to microsoft, you will be given a notice to fix the offending API (happened to be once). You are much better off using the platform specific tools: not only they are much faster, they are also much safer and you won't have problems later on.
You might get away with reading stuff (since reading is not that harmful), but you should be using the winRT APIs each time they are available.
Simply uploading your app to the marketplace just reruns the local tests in their cloud servers: once you submit the actual app (not beta, not tests) for consumers, it will be much more aggressively checked. This is because the store allows specific scenarios for distributing apps in close circles that may break the usual validation rules.
@mcosmin222, one more time: is it your assumptions or personal experience? I don't know how many apps you have in store (I do have a lot) but I never heard that you said. I've used C++ libraries with WP hacks in some of published apps but never had any problem with "aggressive checks". What I know: if you are using some "prohibited" calls, your app will not pass uploading to the store (uploading, not a certification).
P.S. I'll send you personally a link when I publish release Hope, you'll like it
sensboston said:
@mcosmin222, one more time: is it your assumptions or personal experience? I don't know how many apps you have in store (I do have a lot) but I never heard that you said. I've used C++ libraries with WP hacks in some of published apps but never had any problem with "aggressive checks". What I know: if you are using some "prohibited" calls, your app will not pass uploading to the store (uploading, not a certification).
P.S. I'll send you personally a link when I publish release Hope, you'll like it
Click to expand...
Click to collapse
By "hacking" you mean recompiling the code to fit the windows phone toolchain? if so, then you shouldn't have to worry about too many things.
but even so, calling stuff like fopen in locations other than local storage will get your app banned. Even if it makes past the first publication, you can get noticed weeks later or even months (yes, it did happen to me personally).
In most cases, calling C APIs that can potentially break the sandbox (like opening a file in doc library with fopen) will always fail the marketplace verification, eventually. If it hasn't happened to you yet, then you may have not been using such APIs.
No, my C++ code is not accessing other than approved locations but the app has a lot of libс (and of course other C/C++ libs) calls; I'm 99.9% sure it's legitimate and will be not a source of any problem. Otherwise what is the advantages of having C++ compiler?!
As far as I know, just some of API's are prohibited but you will notice it right after local store compatibility test run...
As for "hacks" I mean usage of undocumented ShellChromeAPI calls (including loading hack).
P.S. I've found why <pplawait.h> header is missing. Initially I've created solution with the 12.0 toolset but now I can't (or don't know how to) change it to 14. However creating the new empty universal solution in VS 2015 also gives me toolset 12 by default. What is the toolset 14 for? Windows 10?
sensboston said:
No, my C++ code is not accessing other than approved locations but the app has a lot of libс (and of course other C/C++ libs) calls; I'm 99.9% sure it's legitimate and will be not a source of any problem. Otherwise what is the advantages of having C++ compiler?!
As far as I know, just some of API's are prohibited but you will notice it right after local store compatibility test run...
As for "hacks" I mean usage of undocumented ShellChromeAPI calls (including loading hack).
P.S. I've found why <pplawait.h> header is missing. Initially I've created solution with the 12.0 toolset but now I can't (or don't know how to) change it to 14. However creating the new empty universal solution in VS 2015 also gives me toolset 12 by default. What is the toolset 14 for? Windows 10?
Click to expand...
Click to collapse
The advantage of C++ is the obvious versatility: the standard C++ APIs will work fine for you as long as you stay inside the sandbox (this means you can't access files even in locations that are outside of sandbox but you have permission to them, such as music library). You can use most classic C/C++ libraries without issues as long as you do the interface with the runtime broker yourself. That means using windows runtime APIs instead of classic C APIs when dealing with stuff such as file access, for example. This is a pretty extensive topic and It is rather difficult to explain it all with 100% accuracy, especially when there is lots of docs running around.
You also get deterministic memory management, which is huge in specific scenarios.
Long story short
You will be fine with standard C/C++ when using
any in-memory functions supported by the compiler (you can manipulate data types, string, mutex, etc).
File IO in isolated storage only (applicationData folder)
Threads (although you are better off using threadpool or the like, it is much easier and cleaner). You can also use futures, and std::this_thread.
You will have to use winRT replacement
File system access in any other location than application data (you must use the windows::storage APIs)
sockets, internet access and the like.
any hardware related thing: music&video playerback must be interfaced through winRT (although the underlying decoders can be classic C/C++), messing around with the device sensors.
Retrieving system properties (internet connection state etc)
cross process communications
communicating with other apps
There are also win32 equivalents
mutex, threading, fileIO (isolated storage only)
Media playback with custom rendering pipeline.
Basically, winRT functions as an abstraction layer between the hardware and your code. You can use classic C++ up to the point where you need to interact with the system in any way. At that point, system interaction must be done with winRT. This way, microsoft ensures a higher degree of stability and security for devices.
check this link out for more information on the toolchains. You should be able to use this in VS 2013 as well with windows 8 (this is a compiler feature, has nothing to do with supported platform)
https://paoloseverini.wordpress.com/2014/04/22/async-await-in-c/

How to approach a USB hardware hack? (noob help)

I have a USB audio DSP that's designed to be configured in a Windows environment through an Adobe AIR plugin. Its just a standard plug and play device for control purposes and the transfer of data is by way of XML data.
I want to be able to configure the device in a Linux environment. I did try WINE where I managed to open the plugin but couldn't connect plus is just seems messy.
Normally it takes about 5 seconds to connect. During this time the entire current configuration data on the devices memory is sent to the host, where it updates the GUI (sliders etc).
Is there a tool I can use back in my Window's environment where I can capture the messages sent from the app when 'connect' is clicked? Could I then not just repeat these messages from my Linux environment?
At this stage I would be happy to just receive config data from the device in any shape or form.
So far I have established the DSP is recognised by the bash command
Code:
dmesg -w
How do I open the control pipe to the device's default end point ? (should be only one)
Do I need to retrieve the data from a buffer on the host and how?
How can I confirm each stage in the communication process?
What tools are available to assist external device connections from Linux?
My understanding is fragmented as still relatively new to Linux and have not much experience with hardware connections either.
Any guidance would be greatly appreciated.

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