public Callback(Context context, CameraControlView view, View.IOnTouchListener listener)
     : base(context)
 {
     _context          = context;
     mOpenCvCameraView = view;
     _listener         = listener;
 }
        protected override void OnCreate(Bundle savedInstanceState)
        {
            Log.Info(TAG, "called onCreate");
            base.OnCreate(savedInstanceState);

            Window.AddFlags(WindowManagerFlags.KeepScreenOn);

            SetContentView(Resource.Layout.tutorial3_surface_view);

            mOpenCvCameraView = FindViewById <CameraControlView>(Resource.Id.tutorial3_activity_java_surface_view);

            mOpenCvCameraView.Visibility = ViewStates.Visible;

            mOpenCvCameraView.SetCvCameraViewListener2(this);
            mLoaderCallback = new Callback(this, mOpenCvCameraView, this);
        }