private void flashLightOn() {
  CameraManager cameraManager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);

  try {
    String cameraId = cameraManager.getCameraIdList()[0];
    cameraManager.setTorchMode(cameraId, true);
    flashLightStatus = true;
    imageFlashlight.setImageResource(R.drawable.btn_switch_on);
  } catch (CameraAccessException e) {
  }
}