How do you implement delegates in Swift?

The basic steps to use delegation are the same for both Objective-C and Swift:

  1. Create a delegate protocol that defines the messages sent to the delegate.
  2. Create a delegate property in the delegating class to keep track of the delegate.
  3. Adopt and implement the delegate protocol in the delegate class.

What is iOS delegation pattern?

The core purpose of the delegate pattern is to allow an object to communicate back to its owner in a decoupled way. By not requiring an object to know the concrete type of its owner, we can write code that is much easier to reuse and maintain.

What is delegate in iOS with example?

Example for Delegate Let’s assume an object A calls an object B to perform an action. Once the action is complete, object A should know that B has completed the task and take necessary action. This is achieved with the help of delegates. A is a delegate object of B.

What is delegate and protocol in iOS Swift?

In Swift, declaring a delegate property is just like declaring any other property and you specify the protocol name as the type of the property. You may notice the question mark syntax which indicates that it’s a property with an optional value (there may or may not be an object assigned to it).

Why do we need delegate in Swift?

A few reasons in favor of delegation: Delegation, and the delegation pattern, is a lightweight approach to hand-off tasks and interactions from one class to another. You only need a protocol to communicate requirements between classes. This greatly reduces coupling between classes.

What is delegate and DataSource in Swift?

i.e the UITableViewDelegate protocol has methods such as didSelectRowAtIndexPath for performing actions upon a user selecting a particular row in a table and willDisplayCell which called before delegate use cell to draw row. DataSource type object gives data to another object.

What is the difference between delegate and notification in iOS?

use delegates when you want the receiving object to influence an action that will happen to the sending object. use notifications when you need to inform multiple objects of an event.

What is the use of delegate in iOS?

Delegation is a simple and powerful pattern in which one object in a program acts on behalf of, or in coordination with, another object. A delegate allows one object to send messages to another object when an event happens.

What is the difference between delegate and datasource?

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 delegate in xcode?

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.

What’s the difference between using a delegate and notification in Swift?

Delegate is passing message from one object to other object. It is like one to one communication while nsnotification is like passing message to multiple objects at the same time. All other objects that have subscribed to that notification or acting observers to that notification can or can’t respond to that event.

What is the difference between delegate and notifications?