iOS 之单例，代理，通知，KVO，Block全能解析

taony76

1. //单例
   
2. //.h
   
3. + (Instannce *)shareInstance;
   
4. //.m
   
5. static Instannce *instance = nil;
   
6. @implementation Instannce
   
7. //定义一个创建单例对象的方法
   
8. + (Instannce *)shareInstance {
   
9.     if (instance == nil) {
   
10.         instance = [[Instannce alloc] init];
    
11.     }   
    
12.     return instance;
    
13. }
    
14. //使用alloc的时候调用的方法instancetype
    
15. + (id)allocWithZone:(struct _NSZone *)zone {
    
16.     if (instance == nil) {
    
17.         instance = [super allocWithZone:zone];
    
18.     }  
    
19.     return instance;
    
20. }
    
21. - (id)copy {
    
22.     return self;
    
23. }
    
24. - (id)retain {
    
25.     return self;
    
26. }
    
27. - (NSUInteger)retainCount {
    
28.     //返回无符号最大值
    
29.     return UINT_MAX;
    
30. }
    
31. - (oneway void)release {
    
32.     //什么也不做
    
33. }
    
34. 
    
35. //代理
    
36. //.h
    
37. @protocol GetMessageProtocol <NSObject >
    
38. - (void)getNum:(NSString *)num withPassWord:(NSString *)pass;
    
39. @end
    
40. @property (nonatomic,assign) id<GetMessageProtocol> delegate;
    
41. //.m
    
42. if ([self.delegate respondsToSelector:@selector(getNum:withPassWord:)]) {
    
43.         [self.delegate getNum:num.text withPassWord:passWord.text];
    
44.     }
    
45. #pragma mark - GetMessageProtocol
    
46. - (void)getNum:(NSString *)num withPassWord:(NSString *)pass {
    
47.    
    
48. }
    
49. registerCtrl.delegate = self;
    
50. 
    
51. //通知 注意postNotificationName 必须一致
    
52.     [[NSNotificationCenter defaultCenter] postNotificationName:NotificationName object:self userInfo:dic];  //dic存放在userinfo中   dic中存放要传过去的值是个字典
    
53. //接受通知
    
54.     [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(changeAction:) name:NotificationName object:nil];
    
55. 
    
56. //KVO监听
    
57. /*KVO观察者方法
    
58. keyPath: 监听的属性名
    
59. object： 被观察的对象
    
60. change: 属性值
    
61. context: 上下设备文
    
62. */
    
63.     [registerCtrl addObserver:self forKeyPath:@"属性名称1" options:NSKeyValueObservingOptionNew|NSKeyValueObservingOptionOld context:nil];
    
64.     [registerCtrl addObserver:self forKeyPath:@"属性名称2" options:NSKeyValueObservingOptionNew context:nil];
    
65. //触发的事件
    
66. - (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {
    
67.     //object的值是registerCtrl
    
68.     if ([keyPath isEqualToString:@"属性名称1"]) {
    
69.       
    
70.     }else if ([keyPath isEqualToString:@"属性名称2"]) {
    
71.         
    
72.     }  
    
73. }
    
74. //.h
    
75. @property (nonatomic, copy) NSString *属性名称1;
    
76. @property (nonatomic, copy) NSString *属性名称2;
    
77. //.m   必须通过setter方法改变值或者KVC
    
78. 
    
79. //KVO方式
    
80. //触发的事件
    
81. [indexCollectionView addObserver:self forKeyPath:@"属性名称" options:NSKeyValueObservingOptionNew context:nil];
    
82.         [posterCollectionView addObserver:self forKeyPath:@"pathIndex" options:NSKeyValueObservingOptionNew context:nil];
    
83. - (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {
    
84.     //得到改变后的新值
    
85.     NSInteger index = [[change objectForKey:@"new"] integerValue];
    
86. 
    
87.     }
    
88. }
    
89. 
    
90. //Block  block的返回值  block的名称    block的参数
    
91.     typedef void(^SucccessBlock)(NSString *); //Block的定义
    
92. @property(nonatomic,copy)SucccessBlock loginBlock;  //block的声明  要用copy防止block的循环引用
    
93. _freindBlcok(friends); block的调用
    
94. [[MyXMPPManager shareManager] getFreind:^(NSArray *freinds) {}   //block的赋值 实现

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renxiao2003

IOS人代码还是比较难读懂。