MediaPlus

mCamera = Camera.open(Camera.CameraInfo.CAMERA_FACING_BACK);
 mParams = mCamera.getParameters();
 setCameraDisplayOrientation(this, Camera.CameraInfo.CAMERA_FACING_BACK, mCamera);
 mParams.setPreviewSize(SRC_FRAME_WIDTH, SRC_FRAME_HEIGHT);
 mParams.setPreviewFormat(ImageFormat.NV21); //preview format:NV21
mParams.setFocusMode(Camera.Parameters.FOCUS_MODE_CONTINUOUS_VIDEO);
 m_camera.setDisplayOrientation(90);
 mCamera.setParameters(mParams); // setting camera parameters
 m_camera.addCallbackBuffer(m_nv21);
 m_camera.setPreviewCallbackWithBuffer(this);
 m_camera.startPreview();
 @Override
 public void onPreviewFrame(byte[] data, Camera camera) {
 // TODO Auto-generated method stub
 //data这里就是获取到的NV21数据
 m_camera.addCallbackBuffer(m_nv21);//这里要添加一次缓冲,否则onPreviewFrame可能不会再被回调
 }