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Today, I will talk to you about the analysis of how to implement the OC protocol and agent design pattern, which may not be well understood by many people. In order to make you understand better, the editor has summarized the following contents for you. I hope you can get something according to this article.

Today I'll talk to you about OC content protocols and agent design patterns. The first thing to talk about is the agreement.

I. Agreement

The protocol in OC is similar to the interface, and the methods defined in the protocol are implemented in the class. The protocol is generally used to implement the delegate object. Delegate objects are generally used to define their own behavior or actions, that is, to call their own defined methods, but they do not implement the method and delegate other classes to implement the method.

1. Declaration of the agreement:

HelloProtocol.h

@ required is the default and must be implemented, and @ optional is optional. The protocol has only one .h file, which is not a class itself, but defines an interface that can be implemented by other classes.

2. Implementation of the protocol:

Person.h

Person.m

3. Modify variables with protocols

1) define variables:

IdmyNewVariable

So myNewVatiable follows the MyProtocolName protocol we customized.

2) define the function:

-(void) doSomethingWithThisObject: (id) aObject

Then the parameters of this function need to follow the MyProtocolName protocol we customized.

Second, agent (entrust) design pattern

Proxy: a response in which one object provides an opportunity to change the behavior of another object.

The basic idea is that two objects solve problems together and are generally used for communication between objects.

The basic features of the agent design pattern are as follows:

1. The behavior of objects is simplified and the coupling between objects is minimized.

2. Using agents, generally speaking, there is no need for subclassing.

3. It simplifies our application development, which is easy to implement and flexible. For example:

A.h

A.m

Implementation of delegate object:

B.h

B.m

If so, A can entrust B to do the fun.

The UIApplication class is a very typical example that defines the behavior / action that an application should have. Instead of forcing your UIApplication subclass to accept the status message of the current application and deal with it accordingly. UIApplication passes the message to its delegate object by calling a special method. Then the delegate object can be processed by implementing a protocol called UIApplicationDelegate and then receiving the status message of the current application. For example, important messages such as errors due to insufficient memory, applications being interrupted, etc.

After reading the above, do you have any further understanding of how to implement the analysis of OC protocol and agent design pattern? If you want to know more knowledge or related content, please follow the industry information channel, thank you for your support.

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