ios - 限制 UIPanGestureRecognizer 的移动

Question

我有一个可以使用 UIPanGestureRecognizer 拖动的 UIView 对象，但我只希望它能够向上移动屏幕的 3/4。我不希望它被剪掉，但要达到某个点并且不能再被拖动。到目前为止，我所拥有的只允许它在 Y 轴上移动(这是需要的)。

- (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];
}

感谢您的帮助。

Answer 1

所以只要检查新的Y坐标是否太小。如果 View 太小，请不要更改 View :

- (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;
}