Correctly implement the UIGestureRecognizer state machine #2004
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Description of Change
Apple has an extensive documentation on implementing custom gesture recognizers. For discrete gesture recognizers, like the one implemented in
TouchBehavior
, you are supposed to communicate the state back asPossible
/Failure
/Recognized
. This affects interaction with other gesture recognizers.Previously the
State
was never set and left at the defaultPossible
value (initial value and default afterReset
). This causes simultaneous gesture recognizers on parent views to fire even ifTouchBehavior
recognized the gesture.As a side effect of fixing the state machine, we no longer need to manually prevent simultaneous touches with
ShouldReceiveTouch
behavior override and we can revertShouldRecognizeSimultaneously
to its default behavior of returningfalse
.Linked Issues
PR Checklist
approved
(bug) orChampioned
(feature/proposal)main
at time of PRAdditional information