Gesture Recognizer

In this post I would like to answer the question “What is the difference between a control, a delegate, and a gesture recognizer. The three are major compontents to user interaction with the UIKit Framework and it is not clear to me their responsibilities.

Control

A control is an object assigned to a view that will interact with the user. For example, when a user taps into a text field, a control object will signal that the phone’s keyboard should pop.

Delegate

The only way I can comprehend delegates is thinking of them as event handlers. You define event handlers aheado of time to execute certain code when certain events take place. Delegates are a bit more robust than a simple JS event handler in that it has protocols in place that detect various types of events with default method calls on each event.

Gesture Recognizer

From my very limited knowledge of gesture recognizers, I believe they are a way to customize UI Elements to mimick behaviors of controls. Gesture Recognizers allow a UI Element (Image, label, etc) to detect certain gestures (tap, swipe, pinch, etc) to trigger an event such as showing a keyboard.

In conclusion, I think controls are predefined objects with their own set of methods used to quickly get a interface working for a user. Gesture recognizer’s are objects that can create controls for UI elements and delegates are the objects that will communicate with the control and gesture objects to handle triggered events.