UISwipeGestureRecognizer not working

Question

I have a UIView inside of a UIScrollView, both created using IB. The UIView scrolls horizontally inside the UIScrollView. I want to detect left and right 2 finger swipes.

Answer 1

Try setting the delayContentTouches-property of the UIScrollView to NO, maybe it'll help.

Answer 2

The biggest difference between the sample code and your code is that your code involves a UIScrollView.

Internally, scroll views, table views, and web views all use gesture recognizers to some degree. If you're expecting to receive gestures within those views – gestures that are similar to the ones already supported internally – they will almost certainly be consumed or significantly delayed before you can get to them. Receiving gestures outside or above those views should work fine, if your use case supports it.

Answer 3

I had the same problem and I solved by using UIPanGestureRecognizer instead of UISwipeGestureRecognizer.

To emulate the detection of swipe, we'll play with the speed of gesture in scrollview. If the speed of x direction >= 3000 (for example) the swipe will be detected.

If x>0 it will be a right swipe.

The code I implemented to resolve your situation is: In a uiscrollview named _scroll1:

UIPanGestureRecognizer *pan;
pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(Swipe4ScrollViews:)];
[pan setMinimumNumberOfTouches:2];
[_scroll1 addGestureRecognizer:pan];
[pan release];

With a global BOOL variable named _panning, Swipe4ScrollViews will do the hard job:

-(void)Swipe4ScrollViews:(UIPanGestureRecognizer *)sender 
{
    if(sender.state == UIGestureRecognizerStateBegan) _panning = NO;

    CGPoint v =[sender velocityInView:_scroll1];

    NSLog(@"%f, %f",v.x,v.y);

    if( (abs(v.x) >= UMBRAL) && !_panning)
    {
        _panning = YES;
        [sender cancelsTouchesInView];

        if(v.x>0) NSLog(@"Right");
        else NSLog(@"Left");

        [self doSomething];
    }
}

I encapsulated it on a UIGestureRecognizer subclass: UISwipe4ScrollGestureRecognizer