Question

I am trying to determine a Single Tab on a View inside of a UIScrollView. The Problem is that The UIScrollview catches all the gestures.

What I tried so far:
I override the following method in my UIScrollView:

-(BOOL)touchesShouldBegin:(NSSet *)touches withEvent:(UIEvent *)event inContentView:(UIView *)view
{
    UITouch *touch = [touches anyObject];
    if([touch tapCount]== 2) return YES;

    return NO;
}

This works fine, I can now reach the UITapGestureRecognize on my UIView, unfortunately I can only detect double-taps because the [touch tapCount] == 1 is always beeing called (dragging or zooming in the UIScrollView). But actually the UIScrollview does not need the “Single-Tap-Function”

Is there a way to decide between a drag (Scroll or zoom) and a single Tap inside this method? I cant find it..

-(BOOL)touchesShouldBegin:(NSSet *)touches withEvent:(UIEvent *)event inContentView:(UIView *)view

Thanks in advance
Fabi

Answer 1

It sounds like you only want the tap recognizer to succeed if the touch doesn’t scroll the scroll view. This is pretty easy because the scroll view uses a pan gesture recognizer for scrolling. On iOS 5, you can just do this:

[self.tapRecognizer requireGestureRecognizerToFail:self.scrollView.panGestureRecognizer];

If you want to support older versions of iOS, you have to do this:

for (UIGestureRecognizer *recognizer in self.scrollView.gestureRecognizers) {
    if ([recognizer isKindOfClass:[UIPanGestureRecognizer class]])
        [self.tapRecognizer requireGestureRecognizerToFail:recognizer];