What Is IBOutlet Swift?

Is SwiftUI better than storyboard?

SwiftUI is not replacing storyboards ; it may replace xib in some cases.

But IMHO, SwiftUI is still far from providing the capabilities of xib.

Just read in SwiftUI forum to see how developers are struggling to replicate what is easily done with xib and storyboards and autoLayout..

What is unowned self in Swift?

The most common place you’ll see unowned variables is with closures that declare [unowned self] – this means “I want to reference self inside this closure but I don’t want to own it.” Why unowned rather than weak ? Both would work, but let’s face it: if self is nil inside a closure, something has gone wrong!

Does SwiftUI use UIKit?

Does SwiftUI replace UIKit? No. Many parts of SwiftUI directly build on top of existing UIKit components, such as UITableView . Of course, many other parts don’t – they are new controls rendered by SwiftUI and not UIKit.

Why is IBOutlet weak?

In Mac development an IBOutlet is usually a weak reference: if you have a subclass of NSViewController only the top-level view will be retained and when you dealloc the controller all its subviews and outlets are freed automatically. UiViewController use Key Value Coding to set the outlets using strong references.

Why outlets are weak Swift?

weak is used because in most situations the owner of the outlet isn’t the same as the owner of the view. For example, a view controller doesn’t own someLabel – the view controller’s view does. var because outlets are, by definition, set after initialization.

Is SwiftUI the future?

Before I get into detail I want to make one thing clear: SwiftUI is a remarkable user interface framework, and is 100% absolutely going to be the future of app development on Apple’s platforms.

Do iOS developers use storyboards?

Yes. They do. Storyboard is just another tool in the iOS Dev’s belt.

What is computed property in Swift?

Swift offers us two kinds of property: a stored property is one that saves a value for use later, and a computed property is one that runs some code in order to calculate the value. … The computed property returns a string based on joining the four stored properties into a sentence.

What is lazy property in Swift?

Lazy Stored Properties. A lazy stored property is a property whose initial value isn’t calculated until the first time it’s used. … You must always declare a lazy property as a variable (with the var keyword), because its initial value might not be retrieved until after instance initialization completes.

How do I declare an IBOutlet in Swift?

Simplicity rules in swift. If you have a property defined that you want to make accessible to your storyboards, just add the @IBOutlet attribute before your property. Similarly with @IBAction to connect storyboard actions back to code. class MyViewController: UIViewController { @IBOutlet weak var likeButton: UIButton?

What is retain count in Swift?

Retain Count represents number of owners for a particular object. It is zero till object does not have any owners. Increase in one ownership claim will cause retain count to increase by 1 and decrease will cause it to decrement by 1. Example: – Class A object is created using alloc/init and retain count is 1.

What is strong reference in Swift?

Strong Reference Cycle. In essence, strong references are used to describe the relationship between objects. When an object has a strong reference to another object, this creates a retain cycle that prevents the object that is being referenced from being deallocated and increases the retain count to 1.

What is a sender in Swift?

The sender is the object that called the action. So let’s say if you have 2 UIButtons calling the same function buttonPressed .

How do I add a button in Swift?

How to do this using Swift 3.0. You can create like this and you can add action also like this…. import UIKit class ViewController: UIViewController { override func viewDidLoad() { super. viewDidLoad() // CODE let btn = UIButton(type: UIButtonType.

What is an IBOutlet?

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 weak in Swift?

A weak reference is just a pointer to an object that doesn’t protect the object from being deallocated by ARC. In Swift, all weak references are non-constant Optionals (think var vs. … let ) because the reference can and will be mutated to nil when there is no longer anything holding a strong reference to it.

What is difference between weak and strong in Swift?

A strong reference means that you want to “own” the object you are referencing with this property/variable. In contrast, with a weak reference you signify that you don’t want to have control over the object’s lifetime. A weak reference is like observing the tree from afar. …

How do you call a button action in Swift?

Next we’ll have to link the IBAction Touch Up Inside into our Swift file. To do this, click on the button and open up the Connections Inspector, which is the last tab on the right-hand pane. Now that you have your IBAction outlet in your Swift code you can close out the Interface Builder and focus on the code.

What is optional in Swift?

An optional in Swift is basically a constant or variable that can hold a value OR no value. The value can or cannot be nil. It is denoted by appending a “?” after the type declaration. … This is a big impact on the language Swift itself because what that means is that anything non-optional types can never be nil.