Trigger touchesEnded when dragging outside the UIView - ios

Question

I have a UIView subclass where I handle touches using touchesBegan, touchesMoved, touchesEnded.
I noticed that when I start a touch inside and then drag outside the UIView touchesEnded is not triggered, is there a way to have it called when I'm dragging outside the UIView frame?
Thanks

Answer 1

Use touchesCancelled instead.
- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event
{
}

Answer 2

Pssibly it is calling the - (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event
Please check UIResponder Class Reference
touchesCancelled:withEvent:
Sent to the receiver when a system event (such as a low-memory
warning) cancels a touch event.
- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event
Parameters
touches
A set of UITouch instances that represent the touches for the ending phase of the event represented by event. event
An object representing the event to which the touches belong.
Discussion
This method is invoked when the Cocoa Touch framework receives a
system interruption requiring cancellation of the touch event; for
this, it generates a UITouch object with a phase of
UITouchPhaseCancel. The interruption is something that might cause the
application to be no longer active or the view to be removed from the
window
When an object receives a touchesCancelled:withEvent: message it
should clean up any state information that was established in its
touchesBegan:withEvent: implementation.
The default implementation of this method does nothing. However
immediate UIKit subclasses of UIResponder, particularly UIView,
forward the message up the responder chain. To forward the message to
the next responder, send the message to super (the superclass
implementation); do not send the message directly to the next
responder. For example,
[super touchesCancelled:touches withEvent:event];
If you override this method without calling super (a common use
pattern), you must also override the other methods for handling touch
events, if only as stub (empty) implementations. Availability
Available in iOS 2.0 and later.

Answer 3

You should still be getting touchesMoved in your viewController even you are outside of your view's frame. I would add array to your custom UIView which would keep touch objects that this view is assigned to and implement the following logic:
When you receive touchesBegan - add touch object to array for given UIView where touch coordinates match (you may have to iterate over all your subviews and match coordinates with frame to find the right one)
When you receive touchesMoved - remove touch from UIView's array for previous location and add it to UIView for current location if any
When you receive touchesEnded & touchesCancelled - remove touches from all UIViews arrays
When you remove or add touch object from your custom UIView array you may call your delegate methods (implement observer pattern) because at that point you know if it's really pressed or unpressed event. Keep in mind you may have many touch objects in one array so before calling your delegate check whether you added first object or deleted last one because that's the only case you should call your delegate.
I have implemented such solution in my last game, but instead of UIViews I had virtual buttons.