一、預(yù)覽Camera數(shù)據(jù)

做過Android開發(fā)的人一般都知道，有兩種方法能夠做到這一點：SufaceView、TextureView。

• 下面是使用SurfaceView預(yù)覽數(shù)據(jù)的方式：

SurfaceView surfaceView;
Camera camera;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    surfaceView = (SurfaceView) findViewById(R.id.surface_view);
    surfaceView.getHolder().addCallback(this);

    // 打開攝像頭并將展示方向旋轉(zhuǎn)90度
    camera = Camera.open();
    camera.setDisplayOrientation(90);

}

//------ Surface 預(yù)覽 -------
@Override
public void surfaceCreated(SurfaceHolder surfaceHolder) {
    try {
        camera.setPreviewDisplay(surfaceHolder);
        camera.startPreview();
    } catch (IOException e) {
        e.printStackTrace();
    }
}


@Override
public void surfaceChanged(SurfaceHolder surfaceHolder, int format, int w, int h) {

}

@Override
public void surfaceDestroyed(SurfaceHolder surfaceHolder) {
    camera.release();
}

• 下面是使用TextureView預(yù)覽數(shù)據(jù)的方式：

TextureView textureView;
    Camera camera;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        textureView = (TextureView) findViewById(R.id.texture_view);
        textureView.setSurfaceTextureListener(this);// 打開攝像頭并將展示方向旋轉(zhuǎn)90度
        camera = Camera.open();
        camera.setDisplayOrientation(90);
    }
　　//------ Texture 預(yù)覽 -------
    @Override
    public void onSurfaceTextureAvailable(SurfaceTexture surfaceTexture, int i, int i1) {
        try {
            camera.setPreviewTexture(surfaceTexture);
            camera.startPreview();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @Override
    public void onSurfaceTextureSizeChanged(SurfaceTexture surfaceTexture, int i, int i1) {

    }

    @Override
    public boolean onSurfaceTextureDestroyed(SurfaceTexture surfaceTexture) {
        camera.release();
        return false;
    }

    @Override
    public void onSurfaceTextureUpdated(SurfaceTexture surfaceTexture) {

    }

二、取到NV21的數(shù)據(jù)回調(diào)

Android 中Google支持的Camera Preview CallBack的YUV常用格式有兩種：一種是NV21，一種是YV12,Android一般默認使用的是YCbCR_420_sp(NV21)

• 我們可以配置數(shù)據(jù)回調(diào)的格式：

Camera.Parameters parameters = camera.getParameters();
parameters.setPreviewFormat(ImageFormat.NV21);
camera.setParameters(parameters);

• 通過setPreviewCallback方法監(jiān)聽預(yù)覽的回調(diào)：
  這里面的Bytes的數(shù)據(jù)就是NV21格式的數(shù)據(jù)。