Why do we use delegates in Swift?

Why do we use delegates in Swift?

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 Delegates in iOS?

Delegates are extremely common in iOS development, but fortunately they are easy to understand: a delegate is any object that should be notified when something interesting has happened.

What is delegate and datasource in Swift?

The data source provides information about what to display, like how many rows, and what goes in each row. The delegate tells the tableview what to do when the user selects a row, or whether the user is allowed to edit a row, and other things like that.

How do you implement delegates in Swift?

Key Steps to Delegation

  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.
  4. Call the delegate from the delegating object.

What is difference between protocol and delegate?

We can say Protocol as a set of rules. That rules can be optional or required like we have to use in protocol. Delegates is a message passing technique in objective C and swift. An object has to take care of that message.

What is the difference between delegate and closure in Swift?

Add a new method, get a compiler error, sweet! Closures callbacks: Add a new callback and you’ll be blissfully unaware that you haven’t implemented it.

What are extensions in Swift?

Extensions add new functionality to an existing class, structure, enumeration, or protocol type. This includes the ability to extend types for which you don’t have access to the original source code (known as retroactive modeling). Extensions are similar to categories in Objective-C.

Why delegates are weak iOS?

The reason that objects weakly retain their delegates is to avoid retain cycles. Imagine the following scenario: object a creates b and retains it, then sets itself as b ‘s delegate. a is released by its owner, leaving a retain cycle containing a and b . This is actually a very common scenario.

What is difference between delegate and datasource in Swift?

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’s the difference between using a delegate and notification?

Delegate and notification is a means of communication between objects of iOS applications. A delegate is for one-to-one (bidirectional) communication. Notification allows a class to broadcast events across the entire application. Notifications are for to-many, unidirectional communication.

What is difference between delegate and closure?

If you look at some delegate methods (and nearly all dataSource methods), there is an expected return value. That means the delegating object is asking for the state of something. While a closure could reasonably maintain state or at least deduce state, this is really an object’s role.

What is the difference delegates and callbacks IOS?

Callbacks are similar in function to the delegate pattern. They do the same thing: letting other objects know when something happened, and passing data around. What differentiates them from the delegate pattern, is that instead of passing a reference to yourself, you are passing a function.

How to set delegate in Swift?

Create the Delegate Protocol. Let’s create a delegate protocol that a child or detail view controller might use to tell…

  • Add a Delegate Property. Our delegating class needs a reference to the delegate – but should it be a strong or weak…
  • Adopt and Implement the Delegate Protocol. In our delegate class we tell the compiler that we are…
  • Further Reading.
  • What does ‘delegate’ mean in Swift?

    In this post we will see Delegates and Protocols in Swift. Lets break both the word Delegates and Protocols and try understand what they actually mean. Delegates as the name suggests, delegation i.e. your representative or someone on your behalf. Protocols on the other hand means a set of rules and regulation.

    What is the use of delegate?

    Delegates are similar to C++function pointers,but delegates are fully object-oriented,and unlike C++pointers to member functions,delegates encapsulate both an object instance and a method.

  • Delegates allow methods to be passed as parameters.
  • Delegates can be used to define callback methods.