Question

我有一个视图，我想让用户在选项卡UIButton之后进行绘制，我使用UIPanGestureRecognizer执行此操作，在{{UIPanGestureRecognizer之后添加UIButton此视图1}}触摸，但问题是我完成绘图后重新触摸UIPanGestureRecognizer ??

后我可以删除此UIButton

Answer 1

UIView有一个名为

的方法

- (void)removeGestureRecognizer:(UIGestureRecognizer *)gestureRecognizer

或者，您可以通过使用方法删除其回调来临时禁用UIGestureRecognizer

- (void)removeTarget:(id)target action:(SEL)action

Answer 2

UIPanGestureRecognizer gestureRecognizer.cancelsTouchesInView = NO;

Answer 3

如果视图有多个平移手势识别器，则可以使用关联对象标记特定的手势识别器。

What is objc_setAssociatedObject() and in what cases should it be used?

所以在.m文件的顶部，你会放

static char overviewKey;

然后在您将UIPanGestureRecognizer添加到视图之前，您将使用字符串对其进行标记。

objc_setAssociatedObject(panGesture, &overviewKey, @"pan gesture for drawing", OBJC_ASSOCIATION_RETAIN_NONATOMIC);

[someView addGestureRecognizer:panGesture];

如果要删除UIPanGestureRecognizer，您需要浏览该视图中的所有手势识别器，找到带有该字符串的手势识别器，然后将其删除。

for (UIGestureRecognizer *gesture in someView) {

  NSString *gestureTag= objc_getAssociatedObject(gesture, &overviewKey);


  if (gestureTag==nil) {

    continue;

   }

  if ([gestureTag isEqual:@"pan gesture for drawing"]) {

    [ someView removeGestureRecognizer:gesture ];

  }   
}

将视图添加到视图后删除UIPanGestureRecognizer

3 个答案: