Android 使用Camera2 打开闪光灯

   CameraManager cameraManager= (CameraManager) getSystemService(Context.CAMERA_SERVICE);
  try {
                    String CameraId=cameraManager.getCameraIdList()[0];
                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
                        cameraManager.setTorchMode(CameraId,true);
                    }
                } catch (CameraAccessException e) {
                    e.printStackTrace();
                }