Question

我有一个实现UIView的子类touchesBegan, touchesMoved, touchesEnded。一切都运作良好。然后，我将UIScrollview作为子视图添加到此UIVIew。在UIScrollview内进行的触摸是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（它们被称为在scrollview之外进行的触摸就好了。）

我创建了一个新的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上有效（如果用户将手指拖过滚动视图，它会滚动，但是如果他将它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需要更多的时间在iPad上，但我正在努力想办法可靠地解决这个问题。我确定我错过了一些非常明显的东西。提前谢谢！

编辑可能的解决方案：

经过一些试验和错误，我想出了下面的代码。它似乎在iPhone和iPad上运行良好。使用它的任何原因都可能是一个坏主意？

-(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。

UIScrollview窃取触摸事件

1 个答案: