请教各位关于用camera类做一个关于预览SurfaceView，然后通过 public void onPreviewFrame(byte[] data, Camera camera)获取data转换为RGB值(只需要获取数据流不需要转化为图片)。在这个过程中我的代码总是在手机上有闪退的现象，我不太知道 public void surfaceCreated，public void surfaceChanged，public void surfaceDestroyed；具体是怎么用的。能麻烦您写个Demo吗？谢谢

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

SurfaceView view = (SurfaceView) findViewById(R.id.surface_view);

view.getHolder().addCallback(this);

//view.getHolder().setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);

uStart=(Button) findViewById(R.id.start);

uStart.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View v) {

// TODO Auto-generated method stub

if(camera!=null){

if(isPreview)

camera.stopPreview();

camera.release();

camera=null;

System.out.println("----结束-----");

}

}

});

}

public void surfaceCreated(SurfaceHolder holder) {

}

public void surfaceChanged(SurfaceHolder holder, int format, int width,

int height) {

try{

camera = Camera.open();

camera.setPreviewDisplay(holder);

Parameters params = camera.getParameters();

params.setPreviewSize(300, 200);

camera.setDisplayOrientation(90);

camera.setParameters(params);

camera.startPreview() ;

camera.setPreviewCallback(this);

}catch(Exception e){

e.printStackTrace();

}

isPreview=true;

}

public void surfaceDestroyed(SurfaceHolder holder) {

if(camera != null) camera.release() ;

camera = null ;

}

public void onPreviewFrame(byte[] data, Camera camera) {

Log.i("jefry", "vedio data come ...");

System.out.println("--------运行---------");

}

}

/*int w=camera.getParameters().getPreviewSize().width;

int h=camera.getParameters().getPreviewSize().height;

save(w,h,data);

}

public int decodeYUV420SP(int[] rgb, byte[] yuv420sp, int width, int height)

{

final int frameSize = width * height;

for (int j = 0, yp = 0; j < height; j++) {

int uvp = frameSize + (j >> 1) * width, u = 0, v = 0;

for (int i = 0; i < width; i++, yp++) {

int y = (0xff & ((int) yuv420sp[yp])) - 16;

if (y < 0) y = 0;

if ((i & 1) == 0) {

v = (0xff & yuv420sp[uvp++]) - 128;

u = (0xff & yuv420sp[uvp++]) - 128;

}

int y1192 = 1192 * y;

int r = (y1192 + 1634 * v);

int g = (y1192 - 833 * v - 400 * u);

int b = (y1192 + 2066 * u);

if (r < 0) r = 0; else if (r > 262143) r = 262143;

if (g < 0) g = 0; else if (g > 262143) g = 262143;

if (b < 0) b = 0; else if (b > 262143) b = 262143;

rgb[yp] = 0xff000000 | ((r << 6) & 0xff0000) | ((g >> 2) & 0xff00) | ((b >> 10) & 0xff);

// for(int i=0;i

System.out.println("**********"+rgb[i]);

}

}

writeDataToSD(rgb);

return rgb[width];

}

public void save(int w,int h,byte[] data){

//预览编码为YUV420SP的视频流，需转换为RGB编码

int[] RGB=new int[w*h];

int[] RGBData = new int[w* h];

byte[] mYUVData = new byte[data.length];

System.arraycopy(data,0, mYUVData, 0,data.length);

//RGB[w]=decodeYUV420SP(RGBData,mYUVData,w,h);

for(int i=0;i

System.out.println(RGB[i]);

}

public void writeDataToSD(int[] data){

String dir=Environment.getExternalStorageDirectory().getParent()+"/"+"帧数据流"+"/";

myDir = new File(dir);

if(!myDir.exists()){

//mkdirs()可以创建多级目录

myDir.mkdirs();

}

file=new File(myDir.getAbsoluteFile(),"preview.txt");

if(!file.exists()){

try{

流的对象

RandomAccessFile raf = new RandomAccessFile(file, "rw");

//将文件记录指针移动到最后

raf.seek(file.length());

for(int i = 0;i

// 开始写入数据

raf.writeFloat(data[i]);

}

// 关闭流的使用

raf.close();

}catch(Exception ex){

Toast.makeText(MainActivity.this, "文件写入失败", 1000).show();

}

}

}

}

*/