Question

我不知道这里有什么问题。当用户点击并按住时，我添加了一个视图，当触摸完成后，视图将被删除。这不起作用，我确实看到发送了UIGestureRecognizerStateEnded。

但是，如果我在该状态之外调用[tmpView removeFromSuperview];，则会将其删除而不会出现任何问题。

知道造成这种情况的原因是什么？

  -(void)longTapped:(UILongPressGestureRecognizer*)recognizer {
        UIView *tmpView = [[UIView alloc] init];
        tmpView.backgroundColor = [UIColor greenColor];

        // Position the menu so it fits properly
        tmpView.frame = CGRectMake(0, 100, 320, 250);

        // Add the menu to our view and remove when touches have ended
        if (recognizer.state == UIGestureRecognizerStateBegan) {
            [self.view addSubview:tmpView];
        }
        else if(recognizer.state == UIGestureRecognizerStateEnded){
            [tmpView removeFromSuperview];
        }
    }

Answer 1

第二次调用你的-longTapped：方法时，它会在tmpView变量中实例化一个新的UIView实例，并试图从它的superview中删除它。当长按开始时，您需要在控制器上存储对添加的视图的引用，当它结束时，您需要从超级视图中删除该对象。

@interface myVC ()
@property (nonatomic, weak) UIView *tmpView;
@end

 -(void)longTapped:(UILongPressGestureRecognizer*)recognizer {
    if (recognizer.state == UIGestureRecognizerStateBegan) {
        // Add the menu to our view and remove when touches have ended
        self.tmpView = [[UIView alloc] init];
        self.tmpView.backgroundColor = [UIColor greenColor];

        // Position the menu so it fits properly
        self.tmpView.frame = CGRectMake(0, 100, 320, 250);

        [self.view addSubview:self.tmpView];
    }
    else if(recognizer.state == UIGestureRecognizerStateEnded){
        [self.tmpView removeFromSuperview];
        self.tmpView = nil;
    }
}

UILongPressGestureRecognizer不删除视图

1 个答案: