I'm working with the ios-charts library and I need to do some special logic when the user stops panning over the chart. The library defines the panGestureRecognized method as fileprivate, so I can't subclass/override it. It also doesn't provide any sort of protocol for listening to the pan gestures.
How can I listen to the pan gestures without interrupting the functionality of the chart?
I've considered putting a view on top of the chart and adding a gesture recognizer to that, but it swallows the events and disrupts the regular chart functionality.
The default behavior of any gesture recognizer is to block touches to its subviews. You can change this behavior by writing:
panGesture.cancelsTouchesInView = NO;
To get even more control over simultaneous pan gesture gesture recognition, set your own class as the delegate for the gesture recognizer and use this method:
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
Just return YES in this method if you just care about the two pan gestures to work simultaneously.