[cmake-developers] cmake's built-in support for android using nvidia nsight tegra

Tue Aug 25 10:59:14 EDT 2015

I found a second change required to get hello world SDL2-2.0.3 working on
Android with cmake + nvidia tegra nsight for visual studio 2010.  This
second issue I found with adb logcat:

W/dalvikvm( 5954): No implementation found for native
Lorg/libsdl/app/SDLActivity;.nativeInit:()V
W/dalvikvm( 5954): threadid=11: thread exiting with uncaught exception
(group=0x418d2c80)
E/AndroidRuntime( 5954): FATAL EXCEPTION: SDLThread
E/AndroidRuntime( 5954): Process: org.libsdl.app, PID: 5954
E/AndroidRuntime( 5954): java.lang.UnsatisfiedLinkError: Native method not
found: org.libsdl.app.SDLActivity.nativeInit:()V
E/AndroidRuntime( 5954):        at
org.libsdl.app.SDLActivity.nativeInit(Native Method)
E/AndroidRuntime( 5954):        at
org.libsdl.app.SDLMain.run(SDLActivity.java:510)
E/AndroidRuntime( 5954):        at java.lang.Thread.run(Thread.java:841)
I/AndroidRuntime( 5954): To Report FATAL to activityManagerService

The fix (in case it helps anyone):

extern "C" // required to avoid build link error
{
/* Called before SDL_main() to initialize JNI bindings in SDL library */
extern void SDL_Android_Init(JNIEnv* env, jclass cls);

// required to avoid run found with adb logcat
extern void Java_org_libsdl_app_SDLActivity_nativeInit(JNIEnv* env, jclass
cls, jobject obj);
}

On Tue, Aug 25, 2015 at 1:09 AM, Peter List <pem.list at gmail.com> wrote:

> I worked around that error by editing SDL_android_main.c:
>
> extern "C"
> {
> /* Called before SDL_main() to initialize JNI bindings in SDL library */
> extern void SDL_Android_Init(JNIEnv* env, jclass cls);
> }
>
> So I'm at least able to build again now...  Though it still crashes when I
> try to run the APK...
>
>
>
>
> On Tue, Aug 25, 2015 at 12:57 AM, Peter List <pem.list at gmail.com> wrote:
>
>> I'm now attempting to build a simple SDL2 Android application with
>> CMake's built-in Android support (uses nvidia tegra nsight for visual
>> studio 2010)
>>
>> SDL2-2.0.3 does not appear to have a NativeActivity example so I'm
>> attempting to use its android-project folder that includes
>> "SDL2-2.0.3\android-project\src\org\libsdl\app\SDLActivity.java" instead.
>>
>> I'm able to compile my libpemDemos.so project with SDL2 code this way for
>> armabi-v7a
>>
>> I also compiled libSDL2.so for armabi-v7a using ndk-build (not nvidia
>> tegra nsight), and I'm able to reference it from my pemDemos.vcxproj
>>
>> I verified my pemDemos.vcxproj linker step does includes this:
>> -L"[path]/SDL2-2.0.3/libs/armeabi-v7a" "-lSDL2"
>>
>> However, I'm getting a linker error when I try to add SDL_android_main.c
>> to my build:
>>
>> 1>  pemDemos.dir/Debug/SDL_android_main.o: In function
>> `Java_org_libsdl_app_SDLActivity_nativeInit(_JNIEnv*, _jclass*, _jobject*)':
>> 1>  [path]\SDL2-2.0.3\src\main\android\SDL_android_main.c(23):  undefined
>> reference to `SDL_Android_Init(_JNIEnv*, _jclass*)'
>> 1>collect2.exe : error : ld returned 1 exit status
>>
>> If I comment out the following one line then I can build my
>> libpemDemos.so again:
>>
>> SDL_Android_Init(env, cls);
>>
>> However that of course fails when I try to run it.
>>
>> I don't understand why the linker doesn't see `SDL_Android_Init(_JNIEnv*,
>> _jclass*)'.  I have "-lSDL2" (and I know the linker is finding libSDL.so
>> because it gives an error if I change vcxproj settings to do "-lSDLzzz"
>> instead of "-lSDL").  Plus I even verified that libSDL2.so has
>> SDL_Android_Init():
>>
>> >readelf -Ws [path]\SDL2-2.0.3\libs\armeabi-v7a\libSDL2.so | grep
>> SDL_Android_Init
>>    216: 0002f60d   332 FUNC    GLOBAL DEFAULT    8 SDL_Android_Init
>>
>> So why doesn't my linker step find SDL_Android_Init()?
>>
>> thank you for any leads
>>
>>
>>
>>
>> On Mon, Aug 24, 2015 at 8:20 PM, Peter List <pem.list at gmail.com> wrote:
>>
>>> Per Brad's suggestion, I removed this line from my CMakeLists.txt:
>>>
>>> add_library(${PROJECT_NAME} SHARED ${SRC_LIST})
>>>
>>> And I added these lines:
>>>
>>> set(CMAKE_ANDROID_GUI TRUE)
>>> set(CMAKE_ANDROID_API 19) # Kindle Fire HD 6
>>> set(CMAKE_ANDROID_API_MIN 19) # Kindle Fire HD 6
>>> add_executable(${PROJECT_NAME} ${SRC_LIST})
>>>
>>> I am now able to generate a Visual Studio 2010 pemDemos.sln that
>>> includes a pemDemos.vcxproj with a configuration properties section "Ant
>>> Built".  From inside Visual Studio, I'm able to build an APK and then
>>> ctrl+F5 to run it on my device.
>>>
>>> Unfortunately, cmake did not generate AndroidManifest.xml, so I had to
>>> supply my own using the aforementioned execute_process() with android.bat.
>>>
>>> At this point my app just displays a "Hello World, PemActivity" message
>>> that it gets from "build-android\android\res\layout\main.xml".  So it's not
>>> using "android_native_app_glue.c,h" to point to my "main.cpp" code in
>>> "libpemDemos.so" yet.  So maybe cmake doesn't do that part automatically
>>> for me?  I also don't see a tutorial or simple hello world demo project for
>>> this...  However, I can at least use AndroidNativeApp.vcxproj as a
>>> reference.
>>>
>>> thank you & best regards
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> On Mon, Aug 24, 2015 at 9:49 AM, Brad King <brad.king at kitware.com>
>>> wrote:
>>>
>>>> On 08/23/2015 04:44 PM, Peter List wrote:
>>>> > How do I tell cmake to include "Ant Build" in my vcxproj, so that
>>>> > it will package my project into an APK?  I can generate vcxproj
>>>> > that builds a Tegra-Android *.so file, but it does not build me
>>>> > an APK, and my vcxproj is missing the "Ant Build" property section.
>>>>
>>>> You need to set the ANDROID_GUI target property on an exe:
>>>>
>>>>  http://www.cmake.org/cmake/help/v3.3/prop_tgt/ANDROID_GUI.html
>>>>
>>>> Additional settings have been added in post-3.3 development:
>>>>
>>>>  VS: Add more Nsight Tegra generator Android property settings
>>>>  http://cmake.org/gitweb?p=cmake.git;a=commitdiff;h=8c0afaf4
>>>>
>>>> -Brad
>>>>
>>>>
>>>
>>
>
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