Question: What Is Difference Between Delegate And Datasource In IOS?

What is IndexPath in Swift?

In Swift, an indexPath is a list of indexes that, together, represent the path to a specific location in a tree of nested arrays.

Each index in an index path represents the index in an array of children from one node in the tree to another, deeper, node..

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 datasource in Swift?

The object that acts as the data source of the table view. Availability.

What is protocol in Swift with example?

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.

What is 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.” … Write flexible and extensible code in Swift with protocol-oriented programming.

What is reuseIdentifier in Swift?

As per the Apple’s doc – reuseIdentifier is a string used to identify the cell object if it is to be reused for drawing multiple rows of a table view. Pass nil if the cell object is not to be reused. You should use the same reuse identifier for all cells of the same form. –

What is a delegate iOS?

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.

What is the difference between delegate and notification in iOS?

A delegate uses protocols and creates a has-a relationship between the two classes. One of the other benefits of delegates is that you can return something back to the owning class. Notifications, on the other hand, are more geared towards point to multipoint communication.

What is the difference between delegate and protocol 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.

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).

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.

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.

What is lazy 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 create a custom delegate in Objective-C?

An Objective-C delegate is an object that has been assigned to the delegate property another object. To create one, you define a class that implements the delegate methods you’re interested in, and mark that class as implementing the delegate 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

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.

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.

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 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.

What is delegate method?

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.