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

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