It’s common to have multiple gesture recognizers attached to a single view, all doing different things depending on the user’s taps on your screen. By default, iOS lets them fight for control, but usually you want to execute them in some sort of particular order: one gesture should only be matched if another failed.
For example, here are two gesture recognizers that exist on the same view:
let swipe = UISwipeGestureRecognizer(target: self, action: #selector(executeSwipe)) let tap = UITapGestureRecognizer(target: self, action: #selector(executeTap)) view.addGestureRecognizer(swipe) view.addGestureRecognizer(tap)
A swipe gesture is a tap followed by a linear movement, whereas a tap is just a tap – we need to make sure the swipe gesture has definitely not been recognizer before the tap gesture is checked.
iOS often does a fairly good job of this, but there’s no need to leave it up to chance: if you call
require(toFail:) on the tap gesture recognizer, passing in the swipe recognizer, iOS will definitely make sure they don’t compete:
Available from iOS 3.2
Did this solution work for you? Please pass it on!
Other people are reading…
About the Swift Knowledge Base
This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.
Help support Hacking with Swift
This site is funded by Hacking with Swift supporters who buy my e-books. If you can, please support my work – it comes packed with bonus material!