OBJECTIVE-C Protocol (Agreement) and delegate (delegate, agent)

First, what is the proxy mode?

Proxy mode is a kind of design pattern that is often encountered in OC, what is called proxy mode?

As an example:

There is a baby, he himself will not eat and bathe and so on some things, baby mother to work and very busy, so the baby mother asked for a nanny, so the baby mother and nanny agreed to an agreement, the agreement that the nanny needs to do something, and the nanny is the agent.

Second, the agent mode key points:

A do one thing, but you can not finish, so he find a agent B to do this for him, there is an agreement between them (Protocol,oc in the protocol is similar to Java interface, but it only declares the method), B inherits the protocol to complete a proxy to him things.

Third, case analysis

Here is a classic example of mom and nanny: Mother entrusted the child to the babysitter, so the need to complete the matter into a protocol: the agreement statement is as follows:

Works.h

1 #import<Foundation/Foundation.h>2 /**3 * Define some protocols for babysitting care for children4 * NSObject is the base protocol5  */6 @protocolWorks <NSObject>7 8 /**9 * Nanny Feeding AgreementTen  */ One-(void) feed; A  - /** - * Child Care Agreement the  */ --(void) Lookafter; -  - @end

Implements the protocol for nanny class header file LFNurse.h

1 #import<Foundation/Foundation.h>2 #import "Works.h"3 4 @interfaceLfnurse:nsobject <Works>//Agreement to implement babysitting care for children5 6@property (nonatomic,copy) NSString *Nursename;7 8-(Instancetype) Initwithname: (nsstring*) Nusername;9 Ten @end

Lfnurse.m

1 #import "LFNurse.h"2 3 @implementationLfnurse4 5-(Instancetype) Initwithname: (nsstring*) nusername{6     7     if(self =[Super Init]) {8_nursename =Nusername;9     }Ten     returnSelf ; One } A  --(void) feed{ -NSLog (@"The kid is hungry, give him feeding."); the } -  --(void) lookafter{ -NSLog (@"The kid's starting to get naughty, take care of him."); + } -  + @end

Define MOM header File LFMather.h

1 #import<Foundation/Foundation.h>2 #import "Works.h"3 @classLfnurse;4 5 @interfaceLfmather:nsobject6 7@property (Nonatomic,strong)ID<Works>Delegate;//agent, Mather work busy, need to find a nanny agent to take care of children8@property (nonatomic,copy) NSString *childname;//A child's name.9 Ten-(Instancetype) Initwithname: (nsstring*) name Deleagete: (ID<Works>)Delegate; One-(void) Delegatethingwithsomebody: (lfnurse*) nurse; A  - @end

Implementing File Lfmather.m

1 #import "LFMather.h"2 #import "LFNurse.h"3 4 5 @implementationLfmather6 7-(Instancetype) Initwithname: (nsstring*) name Deleagete: (ID<Works>)Delegate{8 9     if(self =[Super Init]) {TenSelf.childname =name; OneSelf.Delegate=Delegate; A     } -     returnSelf ; - } the  --(void) Delegatethingwithsomebody: (Lfnurse *) nurse{ -      -NSLog (@ "MatherChild's name:%@", self.childname); +[Self.Delegatefeed]; -[Self.DelegateLookafter]; +NSLog (@"Nanny's name:%@", nurse.nursename); A } at  - @end

The main function tests the code:

1 #import<Foundation/Foundation.h>2 #import "LFMather.h"3 #import "Works.h"4 #import "LFNurse.h"5 6 intMainintargcConst Char*argv[])7 {8 9 @autoreleasepool {Ten        OneNSString *name = [[NSString alloc] Initwithformat:@"Little fella?"]; A          -Lfnurse *nurseofdengzhiqi = [[Lfnurse alloc]initwithname:@"Deng Zi Chess"]; -Lfmather *mather =[[Lfmather alloc]initwithname:name Deleagete:nurseofdengzhiqi]; the          - [Mather Delegatethingwithsomebody:nurseofdengzhiqi]; -          -     } +     return 0; -}

Test results:

Iv. Summary:

In the agent, the key to remember is to declare the instance variable of Agent B in the class A that issued the proxy request, so that a can be guaranteed by invoking the B proxy in B to accomplish the thing of a being agent, that is, to explain (proxy) to B.

OBJECTIVE-C Protocol (Agreement) and delegate (delegate, agent)