UIView 平移手势后消失

发布于 2024-10-09 01:08:26 字数 369 浏览 6 评论 0原文

我正在使用以下 IUPanGesture 处理程序。然而，当平移结束时，它正在移动的 UIView 就会消失。我还需要在这段代码中添加其他内容吗？

- (void)pan:(UIPanGestureRecognizer *)gesture
{
  if ((gesture.state == UIGestureRecognizerStateChanged) ||
  (gesture.state == UIGestureRecognizerStateEnded)) {

  CGPoint location = [gesture locationInView:[self superview]];

  [self setCenter:location];
  }
}

原文

I am using the following handler for a IUPanGesture. However when the pan ends, the UIView that it is moving disappears. Do I need to add anything else to this code?

- (void)pan:(UIPanGestureRecognizer *)gesture
{
  if ((gesture.state == UIGestureRecognizerStateChanged) ||
  (gesture.state == UIGestureRecognizerStateEnded)) {

  CGPoint location = [gesture locationInView:[self superview]];

  [self setCenter:location];
  }
}

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我做我的改变 2024-10-16 01:08:26

我不知道它是否在任何地方都有记录，但我根据经验发现，除了 UIGestureRecognizerStateBegan、UIGestureRecognizerStateChanged 和 UIGestureRecognizerStateRecognized 之外的任何手势状态都会有垃圾触摸和位置信息。在许多情况下，代码甚至会在尝试访问不存在的触摸时崩溃。

因此，按如下方式更改条件应该可以解决您遇到的问题：

- (void)pan:(UIPanGestureRecognizer *)gesture
{
  if (gesture.state == UIGestureRecognizerStateChanged) {
    CGPoint location = [gesture locationInView:[self superview]];
    [self setCenter:location];
  }
}

I don't know if it's documented anywhere, but I've found empirically that any gesture states other than UIGestureRecognizerStateBegan, UIGestureRecognizerStateChanged, and UIGestureRecognizerStateRecognized will have garbage touch and location information. In many cases, the code would even crash trying to access a non-existent touch.

So, changing the condition as follows should fix the issue you're having:

- (void)pan:(UIPanGestureRecognizer *)gesture
{
  if (gesture.state == UIGestureRecognizerStateChanged) {
    CGPoint location = [gesture locationInView:[self superview]];
    [self setCenter:location];
  }
}

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