iOS复习笔记11:协议和代理

// MyProtocal.h
@protocal MyProtocal <NSObject>


- (void)protocolDefaultFun();


@required // 默认值，要求实现，不实现会报警告
- (void)protocolRequiredFun();


@optional // 可选实现
- (void)protocolOptionalFun();


@end

// MulProtocal.h
@protocal MulProtocal <NSObject>


- (void)mulProtocolDefaultFun();


@end

// Person.h
#import <Foundation/Foundation.h>


@protocal MyProtocal;
@protocal MulProtocal;
// 或者 @protocal MyProtocal, MulProtocal;


// 只要一个类准遵守了一个协议，就拥有协议中声明的所有方法
@interface Person : Object <MyProtocal, MulProtocal>


@end

// Person.m
#import "Person.h"
#import "MyProtocal.h"
#import "MulProtocal.h"


@implementation Person <MyProtocal, MulProtocal>


- (void)protocolDefaultFun()
{
	
}


- (void)protocolRequiredFun()
{
	
}


- (void)protocolOptionalFun()
{
	
}


- (void)mulProtocolDefaultFun()
{


}


@end

// main.m
#import <Foundation/Foundation.h>
#import "MyProtocal.h"
#import "Person.h"


int main()
{
	// 声明一个遵守了MyProtocal的对象
	NSObject<MyProtocal>* obj1 = [[Person alloc] init];
	obj1 = nil;
	id<MyProtocal> obj2 = [[Person alloc] init];
	obj2 = nil;


	// 


	return 0;
}

四 代理

// ticketDelegate.h


@protocol ticketDelegate <NSObject>


- (int) leftTicketsNumber;


@end

// Agent.h


@protocol ticketDelegate;


@interface Agent : NSObject <ticketDelegate>


@end


// Agent.m
#import "Agent.h"
#import "ticketDelegate.h"


@implementation Agent


- (int) leftTicketsNumber
{
	return 1;
}


@end

// Person.h


@class Agent;
@class ticketDelegate;


@interface Person : NSObject


- (void)buyTicket;


// 代理属性
@property (nonatomic, retain) id <ticketDelegate> delegate;


@end

// Person.m
#import "Person.h"
#import "Agent.h"


@implementation Person


- (void)buyTicket
{
	if ( _delegate & [_delegate leftTicketsNumber] > 0)
	{
		NSLog(@"buy ticket");
	}
}


@end

// main.m
#import "Person.h"
#import "Agent"


int main()
{
	@autopool{
		Person* p = [[Person alloc]init];
		Agent* a = [[Agent alloc] init];
		p.delegate = a;
		[p buyTicket];
	}
	return 0;
}

iOS复习笔记11:协议和代理

原文：http://blog.csdn.net/xufeng0991/article/details/43373843