IOS 代理方式实现实例详解

//// RSLoginService.h// iOSDelegate//// Created by admin on 2016/11/6.// Copyright © 2016年 Reading. All rights reserved.
//#import <Foundation/Foundation.h>@protocol UserLoginStatusDelegate <NSObject>
- (void)userDidLoginIn;
- (void)userWillLoginOut;
@end@interface RSLoginService : NSObject+ (instancetype)sharedInstance;
@property (nonatomic, strong) NSMutableSet *delegates;
- (void)onWillLoginOut;
- (void)onDidLoginIn;
- (void)addDelegate:(id<UserLoginStatusDelegate>) delegate;
- (void)removeDelegate:(id<UserLoginStatusDelegate>) delegate;@end

//// RSLoginService.m// iOSDelegate//// Created by admin on 2016/11/6.

// Copyright © 2016年 Reading. All rights reserved.

//#import "RSLoginService.h"@implementation 

RSLoginService+ (instancetype)sharedInstance{  static id instance;  static dispatch_once_t onceToken;  dispatch_once(&onceToken, ^{ 
   instance = [[RSLoginService alloc] init];  });  return instance;}- (void)onWillLoginOut{  

// do something you need to do before Login out 
 [self.delegates makeObjectsPerformSelector:@selector(userWillLoginOut)];}- (void)onDidLoginIn{  

 // do something you need to do after Login In  
 [self.delegates makeObjectsPerformSelector:@selector(userDidLoginIn)];}- 
(void)addDelegate:(id<UserLoginStatusDelegate>) delegate{  if (![self.delegates containsObject:delegate]) 
{    [self.delegates addObject:delegate];  }
}- (void)removeDelegate:(id<UserLoginStatusDelegate>) 
delegate{  if (![self.delegates containsObject:delegate]) { 
    [self.delegates removeObject:delegate];  }}- (NSMutableSet *)delegates{  if (!_delegates) {    _delegates = [NSMutableSet set];  }  return _delegates;}@end