在本文中，Java创建UI和关节JNI经营层surface直接显示yuv数据（yv12）。发展环境Android 4.4，驰A23平台。
package com.example.myyuvviewer;import java.io.File;import java.io.FileInputStream;import android.app.Activity;import android.os.Bundle;import android.os.Environment;import android.util.Log;import android.view.Surface;import android.view.SurfaceHolder;import android.view.SurfaceHolder.Callback;import android.view.SurfaceView;public class MainActivity extends Activity { final private String TAG = "MyYUVViewer"; final private String FILE_NAME = "yuv_320_240.yuv"; private int width = 320; private int height = 240; private int size = width * height * 3/2; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); nativeTest(); SurfaceView surfaceview = (SurfaceView) findViewById(R.id.surfaceView); SurfaceHolder holder = surfaceview.getHolder(); holder.addCallback(new Callback(){ @Override public void surfaceCreated(SurfaceHolder holder) { // TODO Auto-generated method stub Log.d(TAG,"surfaceCreated"); byte[]yuvArray = new byte[size]; readYUVFile(yuvArray, FILE_NAME); nativeSetVideoSurface(holder.getSurface()); nativeShowYUV(yuvArray,width,height); } @Override public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) { // TODO Auto-generated method stub } @Override public void surfaceDestroyed(SurfaceHolder holder) { // TODO Auto-generated method stub }}); } private boolean readYUVFile(byte[] yuvArray,String filename){ try { // 假设手机插入了SD卡，并且应用程序具有訪问SD的权限 if (Environment.getExternalStorageState().equals( Environment.MEDIA_MOUNTED)) { // 获取SD卡相应的存储文件夹 File sdCardDir = Environment.getExternalStorageDirectory(); // 获取指定文件相应的输入流 FileInputStream fis = new FileInputStream( sdCardDir.getCanonicalPath() +"/" + filename); fis.read(yuvArray, 0, size); fis.close(); return true; } else { return false; } }catch (Exception e) { e.printStackTrace(); return false; } } private native void nativeTest(); private native boolean nativeSetVideoSurface(Surface surface); private native void nativeShowYUV(byte[] yuvArray,int width,int height); static { System.loadLibrary("showYUV"); }}activity_main.xml JNI层。showYUV.cpp(libshowyuv.so)採用动态注冊JNI函数的方法.
#include#include #include #include #include #include #include #include #include #include using namespace android;static sp surface;static int ALIGN(int x, int y) { // y must be a power of 2. return (x + y - 1) & ~(y - 1);}static void render( const void *data, size_t size, const sp &nativeWindow,int width,int height) { ALOGE("[%s]%d",__FILE__,__LINE__); sp mNativeWindow = nativeWindow; int err; int mCropWidth = width; int mCropHeight = height; int halFormat = HAL_PIXEL_FORMAT_YV12;//颜色空间 int bufWidth = (mCropWidth + 1) & ~1;//按2对齐 int bufHeight = (mCropHeight + 1) & ~1; CHECK_EQ(0, native_window_set_usage( mNativeWindow.get(), GRALLOC_USAGE_SW_READ_NEVER | GRALLOC_USAGE_SW_WRITE_OFTEN | GRALLOC_USAGE_HW_TEXTURE | GRALLOC_USAGE_EXTERNAL_DISP)); CHECK_EQ(0, native_window_set_scaling_mode( mNativeWindow.get(), NATIVE_WINDOW_SCALING_MODE_SCALE_CROP)); // Width must be multiple of 32??
? //非常重要,配置宽高和和指定颜色空间yuv420 //假设这里不配置好，以下deque_buffer仅仅能去申请一个默认宽高的图形缓冲区 CHECK_EQ(0, native_window_set_buffers_geometry( mNativeWindow.get(), bufWidth, bufHeight, halFormat)); ANativeWindowBuffer *buf;//描写叙述buffer //申请一块空暇的图形缓冲区 if ((err = native_window_dequeue_buffer_and_wait(mNativeWindow.get(), &buf)) != 0) { ALOGW("Surface::dequeueBuffer returned error %d", err); return; } GraphicBufferMapper &mapper = GraphicBufferMapper::get(); Rect bounds(mCropWidth, mCropHeight); void *dst; CHECK_EQ(0, mapper.lock(//用来锁定一个图形缓冲区并将缓冲区映射到用户进程 buf->handle, GRALLOC_USAGE_SW_WRITE_OFTEN, bounds, &dst));//dst就指向图形缓冲区首地址 if (true){ size_t dst_y_size = buf->stride * buf->height; size_t dst_c_stride = ALIGN(buf->stride / 2, 16);//1行v/u的大小 size_t dst_c_size = dst_c_stride * buf->height / 2;//u/v的大小 memcpy(dst, data, dst_y_size + dst_c_size*2);//将yuv数据copy到图形缓冲区 } CHECK_EQ(0, mapper.unlock(buf->handle)); if ((err = mNativeWindow->queueBuffer(mNativeWindow.get(), buf, -1)) != 0) { ALOGW("Surface::queueBuffer returned error %d", err); } buf = NULL; } static void nativeTest(){ ALOGE("[%s]%d",__FILE__,__LINE__); } static jboolean nativeSetVideoSurface(JNIEnv *env, jobject thiz, jobject jsurface){ ALOGE("[%s]%d",__FILE__,__LINE__); surface = android_view_Surface_getSurface(env, jsurface); if(android::Surface::isValid(surface)){ ALOGE("surface is valid "); }else { ALOGE("surface is invalid "); return false; } ALOGE("[%s][%d]\n",__FILE__,__LINE__); return true; } static void nativeShowYUV(JNIEnv *env, jobject thiz,jbyteArray yuvData,jint width,jint height){ ALOGE("width = %d,height = %d",width,height); jint len = env->GetArrayLength(yuvData); ALOGE("len = %d",len); jbyte *byteBuf = env->GetByteArrayElements(yuvData, 0); render(byteBuf,len,surface,width,height); } static JNINativeMethod gMethods[] = { {"nativeTest", "()V", (void *)nativeTest}, {"nativeSetVideoSurface", "(Landroid/view/Surface;)Z", (void *)nativeSetVideoSurface}, {"nativeShowYUV", "([BII)V", (void *)nativeShowYUV}, }; static const char* const kClassPathName = "com/example/myyuvviewer/MainActivity"; // This function only registers the native methods static int register_com_example_myyuvviewer(JNIEnv *env) { ALOGE("[%s]%d",__FILE__,__LINE__); return AndroidRuntime::registerNativeMethods(env, kClassPathName, gMethods, NELEM(gMethods)); } jint JNI_OnLoad(JavaVM* vm, void* reserved) { ALOGE("[%s]%d",__FILE__,__LINE__); JNIEnv* env = NULL; jint result = -1; if (vm->GetEnv((void**) &env, JNI_VERSION_1_4) != JNI_OK) { ALOGE("ERROR: GetEnv failed\n"); goto bail; } assert(env != NULL); ALOGE("[%s]%d",__FILE__,__LINE__); if (register_com_example_myyuvviewer(env) < 0) { ALOGE("ERROR: MediaPlayer native registration failed\n"); goto bail; } /* success -- return valid version number */ result = JNI_VERSION_1_4; bail: return result; }
Android.mkLOCAL_PATH:= $(call my-dir)include $(CLEAR_VARS)LOCAL_SRC_FILES:= \ showYUV.cpp LOCAL_SHARED_LIBRARIES := \ libcutils \ libutils \ libbinder \ libui \ libgui \ libandroid_runtime \ libstagefright_foundation LOCAL_MODULE:= libshowYUVLOCAL_MODULE_TAGS := testsinclude $(BUILD_SHARED_LIBRARY)生成的so文件拷贝到Java项目里 与src并列的libs/armeabi文件夹下。没有就手动创建文件夹，
这样Eclipse会自己主动把so库打包进apk。
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