How to make scrollView 'bounce' on tap

Question

For example, on the iOS 7/8 lock screen, if you tap rather than drag it to the right, it will have a slight bounce effect. How can I detect the tap gesture (and not have it be confused with the dragging) and recreate a similarly subtle 'bounce' effect? Can anybody share a code example (swift/obj-c) ?

I think this is a great way to show the user that something should be dragged rather than tapped and it doesn't require reading any small indicators.

Answer 1

Add tap gesture to your View like this:

UITapGestureRecognizer *singleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleTap:)];
singleTap.cancelsTouchesInView = NO;
[scrollView addGestureRecognizer:singleTap];

Can be done using UIView's animateWithDuration method in handleTap: method

- (void)handleTap:(UITapGestureRecognizer*)gesture
{
  __block CGRect frame = scrollView.frame;

  [UIView animateWithDuration:0.3 delay:0.0 options: UIViewAnimationOptionCurveLinear
                     animations:^{
                         frame.origin.x += 20.0f;
                         scrollView.frame = frame;
                     }
                     completion:^(BOOL finished){
                         scrollView.frame = frame;
                     }];
}