---
title: "What is delegate pattern in iOS?"  
description: "What is delegate pattern in iOS?"  
author: "Anonymous User"  
published: 2015-08-04  
updated: 2020-09-18  
canonical: https://www.mindstick.com/interview/12754/what-is-delegate-pattern-in-ios  
category: "iphone"  
tags: ["iphone", "ios", "objective c"]  
reading_time: 2 minutes  

---

# What is delegate pattern in iOS?

**Delegation** is a mechanism by which a host object embeds a weak reference (weak in the sense that it’s a simple pointer reference, unretained) to another object—its delegate—and periodically sends messages to the delegate when it requires its input for a task. The host object is generally an “off-the-shelf” framework object (such as an NSWindow or NSXMLParserobject) that is seeking to accomplish something, but can only do so in a generic fashion. The delegate, which is almost always an instance of a custom class, acts in coordination with the host object, supplying program-specific behavior at certain points in the task. Thus delegation makes it possible to modify or extend the behavior of another object without the need for subclassing.Refer: delegate pattern.

## Answers

### Answer by Anonymous User

**Delegation** is a mechanism by which a host object embeds a weak reference (weak in the sense that it’s a simple pointer reference, unretained) to another object—its delegate—and periodically sends messages to the delegate when it requires its input for a task. The host object is generally an “off-the-shelf” framework object (such as an NSWindow or NSXMLParserobject) that is seeking to accomplish something, but can only do so in a generic fashion. The delegate, which is almost always an instance of a custom class, acts in coordination with the host object, supplying program-specific behavior at certain points in the task. Thus delegation makes it possible to modify or extend the behavior of another object without the need for subclassing.Refer: delegate pattern.


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Original Source: https://www.mindstick.com/interview/12754/what-is-delegate-pattern-in-ios

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