What is an IBOutlet in Swift?
The type qualifier IBOutlet is a tag applied to an property declaration so that the Interface Builder application can recognize the property as an outlet and synchronize the display and connection of it with Xcode. An outlet is declared as a weak reference ( weak ) to prevent strong reference cycles.
What is IBAction and IBOutlet in Swift?
@IBAction is similar to @IBOutlet , but goes the other way: @IBOutlet is a way of connecting code to storyboard layouts, and @IBAction is a way of making storyboard layouts trigger code. This method takes one parameter, called sender . It’s of type UIButton because we know that’s what will be calling the method.
What is the purpose of an IBAction?
IBAction and IBOutlets are used to hook up your interface made in Interface Builder with your controller. If you wouldn’t use Interface Builder and build your interface completely in code, you could make a program without using them.
Why is IBOutlet weak?
Outlets that you create will therefore typically be weak by default, because: Outlets that you create to, for example, subviews of a view controller’s view or a window controller’s window, are arbitrary references between objects that do not imply ownership.
What’s the difference between IBOutlet and IBAction?
An IBOutlet lets you reference the view from your controller code. An IBAction lets the view call a method in your controller code when the user interacts with the view.
What is a lazy VAR in Swift?
A lazy var is a property whose initial value is not calculated until the first time it’s called. A lazy stored property is a property whose initial value is not calculated until the first time it is used. You indicate a lazy stored property by writing the lazy modifier before its declaration.
What is ARC in Swift?
Swift uses Automatic Reference Counting (ARC) to track and manage your app’s memory usage. ARC automatically frees up the memory used by class instances when those instances are no longer needed.
What is Interface Builder in iOS?
The Interface Builder editor within Xcode makes it simple to design a full user interface without writing any code. nib files), and macOS and iOS will dynamically create the connection between UI and code when the app is run.
When to use IBOutlet instead of ibaction?
Unlike IBAction, IBOutlet is still required for hooking up properties in code with objects in a Storyboard or XIB. An IBOutlet connection is usually established between a view or control and its managing view controller (this is often done in addition to any IBAction s that a view controller might be targeted to perform by a responder).
What does the @ IBOutlet do in Swift?
In the case of @IBOutlet, this is a connection from an Interface Builder user interface component – e.g. a UIButton – to a property in a view controller or other piece of Swift code.
How is an IBOutlet connection established in a view controller?
An IBOutlet connection is usually established between a view or control and its managing view controller (this is often done in addition to any IBActions that a view controller might be targeted to perform by a responder).
Where do I find the IBOutlet in Xcode?
To the left of the code you should see a black circle with a ring around it, which is Xcode’s visual confirmation that a given @IBOutlet has an active connection. If you’re using the assistant editor with IB in one pane and your code in the other, you can hover over that circle with your mouse pointer to see the UI component highlighted.