从 UIScrollView 转发触摸 - UIButton 问题答案

【问题标题】：Forwarding Touches From UIScrollView - UIButton Issues从 UIScrollView 转发触摸 - UIButton 问题
【发布时间】：2012-09-11 17:18:27
【问题描述】：

我一直在试图弄清楚如何将触摸从 UIScrollView 转发到它的超级视图。原因是某种光标跟随触摸。无论如何，滚动视图都填充了 UIButtons。我转发触摸的代码是在滚动视图子类中使用委托：

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
    [super touchesBegan:touches withEvent:event];
    if ([[self tfDelegate]respondsToSelector:@selector(tfDelegateBegan:)]) {
        [[self tfDelegate]tfDelegateBegan:[touches anyObject]];
    }
        NSLog(@"touches began");
}

-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{
    [super touchesMoved:touches withEvent:event];
    if ([[self tfDelegate]respondsToSelector:@selector(tfDelegateMoved:)]) {
        [[self tfDelegate]tfDelegateMoved:[touches anyObject]];
    }
        NSLog(@"touches moved");
}

-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{
    [super touchesEnded:touches withEvent:event];
    if ([[self tfDelegate]respondsToSelector:@selector(tfDelegateEnded:)]) {
        [[self tfDelegate]tfDelegateEnded:[touches anyObject]];
    }
        NSLog(@"touches ended");
}

-(void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event{
    [super touchesCancelled:touches withEvent:event];
    if ([[self tfDelegate]respondsToSelector:@selector(tfDelegateCancelled:)]) {
        [[self tfDelegate]tfDelegateCancelled:[touches anyObject]];
    }
        NSLog(@"touches cancelled");
}

但是，我了解到 UIScrollviews 通过 UIGestureRecognizers 操作，因此默认情况下甚至不会调用这些方法。我意识到手势识别器在 iOS 5 中公开，但我也需要支持 4.0。我这样做了：

       NSArray *a = [[theScrollview gestureRecognizers]retain];
        for (UIGestureRecognizer *rec in a) {
            if ([rec isKindOfClass:[UIPanGestureRecognizer class]]) {
                NSLog(@"this is the pan gesture");
                rec.cancelsTouchesInView = NO;
            }
        }

这允许手势工作和触摸方法同时被调用。问题是，现在如果您在触摸按钮时尝试滚动，则可以在滚动时按下按钮。通常，滚动取消按钮，并且唯一可以按下按钮的时间是滚动视图没有滚动。这是所需的功能。关于如何实现这一目标的任何建议？

【问题讨论】：

标签： ios uiscrollview uibutton uigesturerecognizer uitouch

【解决方案1】：

也许可以尝试使用一个标志来控制按钮操作，如果滚动视图正在滚动，该标志会阻止事件触发。

BOOL isScrolling = NO;

- (void) scrollViewWillBeginDragging:(UIScrollView *)scrollView {
    isScrolling = YES;
}

- (void) scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate {
    isScrolling = NO;
}

- (void) didTapButton {

    if(isScrolling)
        return;

    //Do Button Stuff
}

【讨论】：