UITouch Event Propagation To Background UIViews
- by drewww
I'm having troubles getting any UIView that's not the foreground UIView to receive UITouch events. I'm building an all-Core Graphics-app, so I'm not using any built in UIViews or IB or anything - everything is programmatically constructed and drawn into.
Here's my view hierarchy:
Root View
Type A Container
Type A View
Type A View
Type A View
Type B Container
Type B View
Type B View
Type B View
The containers are just vanilla UIView objects that I create programmatically and add instances of Type A and B to when they're created. I did this originally to make hitTesting easier—Type A objects can be drag-and-dropped onto Type B objects. Type A objects receive touch events fine, but Type B objects (which are contained by Type B Container which is behind Type A Container) don't receive touch events. Both containers occupy the entire screen; they're basically just convenience containers.
If I pull Type B Container to the front (eg [self.view bringSubviewToFront:Type B Container]) it receives events properly, but then the Type A Container doesn't get events.
How do I propagate events from the view that's on top? Both views occupy the entire screen, so it makes sense that the top-most view is catching the events, but how should I get it to pass those events on to Type B Container? I could inject some code in the container that passes the touch events back to the main ViewController which can pass them on to Type B Container but that feels really messy to me. Is there a nicer way to not have the Type A Container stop propagation? What's the best practice here?
