Android实现静默拍照功能

public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {
 private SurfaceHolder mHolder;
 private Camera mCamera;

 public CameraPreview(Context context, Camera camera) {
  super(context);
  //初始化Camera对象
  mCamera = camera;
  //得到SurfaceHolder对象
  mHolder = getHolder();
  //添加回调，得到Surface的三个声明周期方法
  mHolder.addCallback(this);
  // deprecated setting, but required on Android versions prior to 3.0
  mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
 }

 @Override
 public void surfaceCreated(SurfaceHolder holder) {
  try {
   //设置预览方向
   mCamera.setDisplayOrientation(90);
   //把这个预览效果展示在SurfaceView上面
   mCamera.setPreviewDisplay(holder);
   //开启预览效果
   mCamera.startPreview();
  } catch (IOException e) {
//   Log.d(TAG, "Error setting camera preview: " + e.getMessage());
  }

 }

 @Override
 public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
  if (holder.getSurface() == null) {
   return;
  }
  //停止预览效果
  mCamera.stopPreview();
  //重新设置预览效果
  try {
   mCamera.setPreviewDisplay(mHolder);
  } catch (IOException e) {
   e.printStackTrace();
  }
  mCamera.startPreview();
 }

 @Override
 public void surfaceDestroyed(SurfaceHolder holder) {

 }
}

public class CameraActivity extends BaseActivity{

 private FrameLayout cameraFrame;
 private Camera mCamera;
 private TextView cameraTv;
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_camera);


  cameraFrame = (FrameLayout) findViewById(R.id.camera_frame);
  cameraTv = (TextView) findViewById(R.id.camera_tv);

  int numberOfCameras = Camera.getNumberOfCameras();// 获取摄像头个数
  //遍历摄像头信息
  for (int cameraId = 0; cameraId