![Связка с Java-кодом (JNI)Хороший стиль — хранить нативные вызовы в отдельном классеpublicclassAudioCoreJNI {static { System.loadLibrary("core");Log.d(AudioCoreJNI.class.getSimpleName(), "library loaded");} ...privatenativevoidnativeSetLogging(boolean on);privatenativebooleannativeInitialize(int[] configuration);privatenativeintnativeGetOutputBufferSize(intsamplesCount); privatenativebyte[] nativeFlush();privatenativevoidnativeClose();}](https://image.slidesharecdn.com/nativedevelopment-110507092514-phpapp01/85/Native-Development-8-320.jpg)
![OnLoad()JNINativeMethod methods[] = {{"nativeInitialize", "([I)Z", (bool*)initialize },{"nativeEncode", "([BII[B)I", (void*)encode}};intjniRegisterNativeMethods(JNIEnv* env, constchar* className, constJNINativeMethod* gMethods, intnumMethods) {jclassclazz;clazz = env->FindClass("com/shaubert/android/aaf/jni/AudioCoreJNI");if (clazz != NULL) { if (env->RegisterNatives(clazz, gMethods, 2) >= 0) { return 0; } } return -1;}jintJNI_OnLoad(JavaVM* vm, void* reserved) {JNIEnv* env = NULL;if (vm->GetEnv((void**) &env, JNI_VERSION_1_4) == JNI_OK) { if (jniRegisterNativeMethods(env, classPathName, methods, 2) > 0) { return JNI_VERSION_1_4; } }return -1;}](https://image.slidesharecdn.com/nativedevelopment-110507092514-phpapp01/85/Native-Development-10-320.jpg)
Native Development
- 2. Для чего?Игры, в которых много графикиРесурсоемкие алгоритмы обработкиimage/audio processingПодключение библиотек на C/C++FAAC, LAME, FFMPEG…Выйти за пределы кучи в Java (≈24MB)android.os.Debug.getNativeHeapAllocatedSize()
- 3. ПодготовкаСкачать Android NDK (Revision 5b Jan 10)При распаковке zip избегайте путей с пробелами. (всегда и везде избегайте путей с пробелами)Добавить в PATH путь к распакованному NDKCygwin for Win (with gcc/make/smth else)gcc/make/smthelsefor *nix
- 4. NDKndk-build скрипт в корнеlib и include – либыи h-ники, которые можно подключитьsamples – примерыdocs - хелп
- 5. Native projectНаходится в папке jni в корне Android-проектаСодержит android.mk — make-файлы для ndk-build
- 7. Single project’s Android.mk LOCAL_PATH := $(call my-dir) include$(CLEAR_VARS) LOCAL_ARM_MODE := arm LOCAL_CFLAGS := $(LOCAL_CFLAGS) -O3 LOCAL_CPPFLAGS := $(LOCAL_CPPFLAGS) -O3 LOCAL_MODULE := core LOCAL_SRC_FILES := AacEncoder.cpp \ AudioEncodingController.cpp \ AudioEncodingJni.cpp \ EncoderConfiguration.cpp \ LameEncoder.cpp LOCAL_LDLIBS := -ldl -llog -lc LOCAL_STATIC_LIBRARIES := faac lame LOCAL_C_INCLUDES := $(LOCAL_PATH)/../faac-1.28/include/ \$(LOCAL_PATH)/../lame-3.98.4/include/ \$(LOCAL_PATH)/../libogg-1.2.2/include/ogg/ include$(BUILD_SHARED_LIBRARY)requiredoptimizationrequireddependenciesgood stylerequired
- 8. Связка с Java-кодом (JNI)Хороший стиль — хранить нативные вызовы в отдельном классеpublicclassAudioCoreJNI {static { System.loadLibrary("core");Log.d(AudioCoreJNI.class.getSimpleName(), "library loaded");} ...privatenativevoidnativeSetLogging(boolean on);privatenativebooleannativeInitialize(int[] configuration);privatenativeintnativeGetOutputBufferSize(intsamplesCount); privatenativebyte[] nativeFlush();privatenativevoidnativeClose();}
- 9. Связка с Java-кодом (JNI)#include<jni.h>JNIEXPORTjbooleaninitialize(JNIEnv* env, jobjectthiz, jintArray configuration) {voidJava_com_example_nativeaudio_NativeAudio_createEngine (JNIEnv* env, jclassclazz){
- 10. OnLoad()JNINativeMethod methods[] = {{"nativeInitialize", "([I)Z", (bool*)initialize },{"nativeEncode", "([BII[B)I", (void*)encode}};intjniRegisterNativeMethods(JNIEnv* env, constchar* className, constJNINativeMethod* gMethods, intnumMethods) {jclassclazz;clazz = env->FindClass("com/shaubert/android/aaf/jni/AudioCoreJNI");if (clazz != NULL) { if (env->RegisterNatives(clazz, gMethods, 2) >= 0) { return 0; } } return -1;}jintJNI_OnLoad(JavaVM* vm, void* reserved) {JNIEnv* env = NULL;if (vm->GetEnv((void**) &env, JNI_VERSION_1_4) == JNI_OK) { if (jniRegisterNativeMethods(env, classPathName, methods, 2) > 0) { return JNI_VERSION_1_4; } }return -1;}
- 11. Native logging#include<android/log.h>#define LOGD(...) __android_log_print(ANDROID_LOG_DEBUG, “LOG_TAG", __VA_ARGS__)if (logging) { LOGD(“test logging %s %d...“, “hello”);}
- 12. Compiling
- 13. Compiling
- 16. Reading crash logshttp://code.google.com/p/android-ndk-stacktrace-analyzer/logcat from your android device, containing a stacktraceasm file of the library being debugged. You generate this file by using the NDK's objdumptool: ...android-ndk/toolchains/arm-linux-androideabi-4.4.3/prebuilt/…/ arm-eabi-objdump-S mylib.so >mylib.asmUse the script by running: python parse_stack.py <asm-file> <logcat-file>Output:
- 17. Спасибо за вниманиеПрезентацию подготовил Шауберт Александрshaubert.alexander@gmail.comСпециально для Android May Days 2011