What is UIResponder in Swift?
What is UIResponder in Swift?
Overview. Responder objects—that is, instances of UIResponder —constitute the event-handling backbone of a UIKit app. Many key objects are also responders, including the UIApplication object, UIViewController objects, and all UIView objects (which includes UIWindow ).
What is UIResponder chain?
The responder chain is a series of linked responder objects. It starts with the first responder and end with the app object. If the first responder cannot handle an event, it forwards the event to the next responder in the responder chain. A responder object is an object that can respond to and handle events.
What is UIKit app delegate?
The app delegate is effectively the root object of your app, and it works in conjunction with UIApplication to manage some interactions with the system. Like the UIApplication object, UIKit creates your app delegate object early in your app’s launch cycle so it is always present. Configuring your app’s scenes.
How does a UIResponder not handle an event?
If the text field does not handle an event, UIKit sends the event to the text field’s parent UIView object, followed by the root view of the window. From the root view, the responder chain diverts to the owning view controller before directing the event to the window.
What is a UIViewController?
A UIViewController is an object which manages the view hierarchy of the UIKit application. The UIViewController defines the shared behavior and properties for all types of ViewController that are used in the iOS application. The UIViewController class inherits the UIResponder class.
What does CGRect mean?
A structure that contains the location and dimensions of a rectangle.
What is the difference between a delegate and a responder?
A delegate is an object that acts on behalf of, or in coordination with, another object when that object encounters an event in a program. The delegating object is often a responder object–that is, an object inheriting from NSResponder in AppKit or UIResponder in UIKit–that is responding to a user event.
Which is an example of a delegate in a program?
A delegate is an object that acts on behalf of, or in coordination with, another object when that object encounters an event in a program. The delegating object is often a responder object—that is, an object inheriting from NSResponder in AppKit or UIResponder in UIKit—that is responding to a user event.
Which is an example of a UIResponder in iOS?
In short, UIResponder instances represents objects that can handle and respond to arbitrary events. Many things in iOS are UIResponders, including UIView, UIViewController, UIWindow, UIApplication and UIApplicationDelegate.
How does a delegate keep reference to the delegating object?
The delegating object keeps a reference to the other object–the delegate–and at the appropriate time sends a message to it. The message informs the delegate of an event that the delegating object is about to handle or has just handled.