UIScrollview 窃取触摸事件

Question

我有一个实现touchesBegan, touchesMoved, touchesEnded 的子类UIView。一切运作良好。然后，我在这个UIVIew 中添加了一个UIScrollview 作为子视图。在UIScrollview 中进行的触摸是not forwarded back up the responder chain to the parent view，因此我的 UIView 的触摸方法永远不会被调用（它们被调用用于在滚动视图之外进行的触摸就好了）。

我像这样创建了一个新的 UIScrollView 类别：

@implementation UIScrollView (forwardTouches)

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{

    // If not dragging, send event to next responder
    if (!self.dragging){
        [self.nextResponder touchesBegan: touches withEvent:event];
        [self setScrollEnabled:NO];
        NSLog(@"touchesBegan");
    }
    else{
        NSLog(@"touchesBegan-else");
        [super touchesEnded: touches withEvent: event];
    }
}
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{

    // If not dragging, send event to next responder
    if (!self.dragging){
        [self.nextResponder touchesMoved: touches withEvent:event];
        NSLog(@"touchesMoved");
    }
    else{
        NSLog(@"touchesMoved - else");
        [super touchesEnded: touches withEvent: event];
    }
}
-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{

    // If not dragging, send event to next responder
    if (!self.dragging){
        [self.nextResponder touchesEnded: touches withEvent:event];
        [self setScrollEnabled:YES];
        NSLog(@"touchesEnded");
    }
    else{
        NSLog(@"touchesEnded - else");
        [super touchesEnded: touches withEvent: event];
    }
}

这实际上似乎在 iPhone 上按预期工作（即：如果用户将手指拖过滚动视图，它会滚动，但如果他将手指放在视图上并且不移动它，则父视图的 touchesBegan 方法火灾），但它不适用于 iPad。据推测，self.dragging 需要更多时间在 iPad 上，但我正在努力寻找可靠解决此问题的方法。我确定我遗漏了一些非常明显的东西。提前致谢！

使用可能的解决方案进行编辑：

经过反复试验，我想出了下面的代码。它似乎在 iPhone 和 iPad 上运行良好。为什么使用它可能是个坏主意？

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{

    NSArray * myDataArray = [NSArray arrayWithObjects:touches, event, nil];

    // If not dragging, send event to next responder
    if (!self.dragging){
        [self performSelector:@selector(forwardTouches:) withObject:myDataArray afterDelay:0.5];
    }
    else{
        NSLog(@"touchesBegan-else");
        [super touchesEnded: touches withEvent: event];
        [NSObject cancelPreviousPerformRequestsWithTarget:self];
    }
}

-(void)forwardTouches:(NSArray *)array{
    NSSet * mySet = [array objectAtIndex:0];
    UIEvent * myEvent = [array objectAtIndex:1];

    if (!self.dragging){
        [self.nextResponder touchesBegan:mySet withEvent: myEvent];
        [self setScrollEnabled:NO];
    }
}

-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{

    // If not dragging, send event to next responder
    if (!self.dragging){
        [self.nextResponder touchesMoved: touches withEvent:event];
        NSLog(@"touchesMoved");
    }
    else{
        NSLog(@"touchesMoved - else");
        [super touchesEnded: touches withEvent: event];
        [NSObject cancelPreviousPerformRequestsWithTarget:self];
    }
}
-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{

    // If not dragging, send event to next responder
    if (!self.dragging){
        [self.nextResponder touchesEnded: touches withEvent:event];
        [self setScrollEnabled:YES];
        NSLog(@"touchesEnded");
    }
    else{
        NSLog(@"touchesEnded - else");
        [super touchesEnded: touches withEvent: event];
        [NSObject cancelPreviousPerformRequestsWithTarget:self];
    }
}

Answer 1

上面的代码不是一个好的计划。 如果你想让超级视图有机会处理子视图中出现的触摸，你应该使用手势，而不是改变触摸的转发，这是危险的。