What Does Gesture Recognizer Mean?
A gesture recognizer is a code function in the iOS Apple operating system (OS) that helps a mobile device respond to specific touch-screen inputs from a user. A UIGestureRecognizer acts as an abstract base class for various sub-classes in the UIKit – commonly known as gesture recognizers. Developers can use existing gesture recognizers to support responses to a set of common gestures, or create additional gesture recognizers.
Techopedia Explains Gesture Recognizer
Existing gesture recognizers include support for pinching in and out, panning and dragging and various types of quick taps. There is also a class for a "long press" or "touch and hold" input, as well as rotating and swiping actions on the touchscreen.
Although the gesture recognizer class allows the development of custom responses, experts advise developers to adhere to normal standards expected by users. Changing responses within a given application can profoundly confuse one of the most important, intuitive aspects of the iOS user interface, which takes users some time to learn and should be as easy as possible to understand.