How Do I Use Delegates In Swift?

What is delegate in iOS with example?

Delegate is simply just a means of communication between objects of iOS applications.

You can think delegation as a simple way of connecting objects and communicate with each other.

In other words we can say that delegate allows one object to send message to other object when any event occurs..

Can Swift protocols have properties?

A protocol can require any conforming type to provide an instance property or type property with a particular name and type. The protocol doesn’t specify whether the property should be a stored property or a computed property—it only specifies the required property name and type.

What are swift delegates?

Delegates are a design pattern that allows one object to send messages to another object when a specific event happens. … Imagine an object A calls an object B to perform an action.

Why delegates are weak iOS?

For delegation patters in iOS, the delegated object is the parent, because there is no need for the delegate caller to exist without the delegated object. … When you define a delegate object as property, it’s used a weak reference in the object it is defined in(lets say A, i.e. the delegate object is a property of A).

What is delegate and datasource in Swift?

A data source is an outlet held by NSView and UIView objects such as table views and outline views that require a source from which to populate their rows of visible data. The data source for a view is usually the same object that acts as its delegate, but it can be any object.

What are delegate methods?

A delegate method is a method that the delegate object is expected to implement. … A delegate is simply a reference to another object and a delegate method is a method of the delegate. A delegate method implements the callback mechanism which usually takes the sender as one of the parameter to be called.

What are delegates and protocols in IOS?

Delegates are a use of the language feature of protocols. The delegation design pattern is a way of designing your code to use protocols where necessary. In the Cocoa frameworks, the delegate design pattern is used to specify an instance of a class which conforms to a particular protocol.

How do I create a custom delegate in Swift?

How To Create A Custom Delegate In SwiftThe Delegate Pattern in Swift.Create A Delegate Protocol.Extend A Delegate Protocol.Implement A Custom Delegate.How To Use A Custom Delegate.Creating Optional Delegate Methods.Jan 3, 2021

How do delegates work in Swift?

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.

How do I use protocol and delegate in Swift 4?

Here are the simple steps that you can follow to implement delegates in Objective-C.Create a protocol.Create a delegate property in the class that performs the assigned task.Once the task is complete, it can be used to return the result.Implement the protocol.Nov 9, 2020

What is difference between protocol and delegate in Swift?

Protocol is a set of methods (either optional or required) that would be implemented by the class which conforms to that protocol. While, delegate is the reference to that class which conforms to that protocol and will adhere to implement methods defined in protocol. Have a look at this Apple doc for more detail.

What is difference between delegate and datasource in IOS?

A data source is almost identical to a delegate. The difference is in the relationship with the delegating object. Instead of being delegated control of the user interface, a data source is delegated control of data.

What is use of protocol in Swift?

Protocol is a very powerful feature of the Swift programming language. Protocols are used to define a “blueprint of methods, properties, and other requirements that suit a particular task or piece of functionality.”

Why we use delegates in Swift?

Delegation is used for everything from handling table view events using UITableViewDelegate , to modifying cache behavior using NSCacheDelegate . The core purpose of the delegate pattern is to allow an object to communicate back to its owner in a decoupled way.

Why delegates are weak in Swift?

With using lazy keyword we are not initializing delegate which means there is no memory leak right now. Let’s break that. Object will be created and there will be memory leak. … Therefore, if the object conforming to the protocol needs to be stored in a weak property then the protocol must be a class-only protocol.