What is delegate in Swift?

What is delegate 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.

What is protocol and delegate 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.

What is the protocol in Swift?

Protocols provide a blueprint for Methods, properties and other requirements functionality. It is just described as a methods or properties skeleton instead of implementation. Methods and properties implementation can further be done by defining classes, functions and enumerations.

How do I use protocol and delegate in Swift 4?

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.

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.

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 the difference between delegate and protocol?

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.

What is difference between delegate and datasource in iOS?

What is the purpose of protocols Swift?

Protocols are used to define a “blueprint of methods, properties, and other requirements that suit a particular task or piece of functionality.” Swift checks for protocol conformity issues at compile-time, allowing developers to discover some fatal bugs in the code even before running the program.

What is difference between protocol and delegate in Swift?

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.

How does the delegation protocol work in Swift?

When the delegat or class gets initialized, a second step is often to immediately assign an instance of the class that’s adopted the delegate protocol to its delegate property so that everything is “wired up”. Working with the delegation pattern in practice usually involves interacting with the protocol from the delegate end of things.

Where do you call a delegate in Swift?

Adopt and implement the delegate protocol in the delegate class. Call the delegate from the delegating object. Note that there are a couple of differences between Swift and Objective-C support for protocols:

How does protocol work in a swift contract?

To the delegat or class, the protocol is a guarantee that some behavior will be supplied by the other party (the delegate). To the delegate class, the protocol is a set of obligations – things it must implement when it “signs the contract”, or in Swift terms, “adopts the protocol”.

What is the protocol of the delegate class?

To the delegate class, the protocol is a set of obligations – things it must implement when it “signs the contract”, or in Swift terms, “adopts the protocol”.