限制UIPanGestureRecognizer移动

Question

我有一个可以使用UIPanGestureRecognizer拖动的UIView对象，但我希望它只能向上移动屏幕的3/4。我不想让它被剪掉，而是想到达某个点，不能再拖下去了。到目前为止，我只允许它在Y轴上移动(这是所需的)。

- (IBAction)panGesture:(UIPanGestureRecognizer *)recognizer
{
  CGPoint translation = [recognizer translationInView:self.view];
  recognizer.view.center = CGPointMake(recognizer.view.center.x, 
                                       recognizer.view.center.y + translation.y);
  [recognizer setTranslation:CGPointMake(0, 0) inView:self.view];
}

谢谢你的帮助。

Answer 1

因此，只需检查新的Y坐标是否会太小。如果视图太小，请不要更改：

- (IBAction)panGesture:(UIPanGestureRecognizer *)recognizer
{
  CGPoint translation = [recognizer translationInView:self.view];
  [recognizer setTranslation:CGPointMake(0, 0) inView:self.view];

  CGPoint center = recognizer.view.center;
  center.y += translation.y;
  if (center.y < self.yMin)
    return;
  recognizer.view.center = center;
}

Answer 2

它对我来说很好。

  CGPoint currentTouchPoint = [gesture translationInView:self.bottomView];

    if (fabsf(currentTouchPoint.x) > fabsf(currentTouchPoint.y))    {
        // avoid horizontal movement of pan geuture.
        return;
    }

谢谢,

纳维恩·山

Answer 3

实现下面的手势委托，并检查其中的条件。从该代理返回YES或NO将使手势处于活动和非活动状态。

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch;