用UIPanGestureRecognizer监听滑动延迟

Question

我用UIPanGestureRecognizer加在一个View上用来监听手指的滑动，然后根据 translation 的值来修改view的frame，但是我发现这样修改，view的动画并不能实时反应，手指滑动快了，就会出现延迟现象。
代码如下：

- (void)slidePanAction:(UIPanGestureRecognizer *)recognizer
{
    CGPoint translation = [recognizer translationInView:self.movingView];
    if(recognizer.state == UIGestureRecognizerStateChanged) { // sliding.
        self.movingView.frame = CGRectMake(self.origin.x + translation.x, self.origin.y + translation.y,
                                           self.movingView.frame.size.width, self.movingView.frame.size.height);
    }
    else if(recognizer.state == UIGestureRecognizerStateEnded) { // end slide.
        self.origin = CGPointMake(self.movingView.frame.origin.x, self.movingView.frame.origin.y);
    }
}

- (void)viewDidLoad {
    [super viewDidLoad];
    
    self.movingView = [[UILabel alloc] initWithFrame:CGRectMake(10.0f, 10.0f, 100.0f, 100.0f)];
    self.movingView.backgroundColor = [UIColor redColor];
    [self.view addSubview:self.movingView];
    self.origin = CGPointMake(10.0f, 10.0f);

    UIPanGestureRecognizer *panRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(slidePanAction:)];
    [self.view addGestureRecognizer:panRecognizer];
}

如果我要做这种view跟着手指运动，还有什么其他的方案吗？还是我这个用法用的不对？

Answer 1

可以在view中重写

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event

达成此目的。

另外gesture recognizer正常情况不会出现延迟。请检查是否每次对位置的提交都发起了动画（比如layer.position = newPosition默认情况下是有动画的，在触摸移动时设置layer.position且不关闭动画，移动会有明显延迟）