代替代理

1.自定义一个View控件，并添加一个按钮

- (instancetype)initWithFrame:(CGRect)frame {
    self = [super initWithFrame:frame];
    if (self) {
        self.backgroundColor = [UIColor blueColor];
        
        UIButton *btn = [UIButton buttonWithType:UIButtonTypeCustom];
        btn.frame = CGRectMake(10, 10, 50, 50);
        btn.backgroundColor = [UIColor redColor];
        [self addSubview:btn];
        [btn addTarget:self action:@selector(clickButton:) forControlEvents:UIControlEventTouchUpInside];
    }
    
    return self;
}

- (void)clickButton:(UIButton *)btn {

}

2.如果使用代理，需要创建一个delegate属性，在clickButton:中执行[self.delegate xxx],并在vc中实现代理方法。
3.但通过RAC就方便许多，直接在VC中添加自定义view

@property (nonatomic, strong) MyView *v;

4.要接收点击事件直接执行

    [[_v rac_signalForSelector:@selector(clickButton:)] subscribeNext:^(RACTuple * _Nullable x) {
        NSLog(@"%@", x);
    }];

5.运行结果如图：

运行结果

代替KVO

1.代替KVO有两种方式

     [_v rac_observeKeyPath:@"frame" options:NSKeyValueObservingOptionNew observer:nil block:^(id value, NSDictionary *change, BOOL causedByDealloc, BOOL affectedOnlyLastComponent) {
         NSLog(@"%@", value);
     }];
     [[_v rac_valuesForKeyPath:@"frame" observer:nil] subscribeNext:^(id  _Nullable x) {
         NSLog(@"%@", x);
     }];

监听事件

1. 监听按钮点击事件

    [[_btn rac_signalForControlEvents:UIControlEventTouchUpInside] subscribeNext:^(__kindof UIControl * _Nullable x) {
        NSLog(@"%@", x);
    }];

2. 监听文本框输入

    [[_tf rac_textSignal] subscribeNext:^(NSString * _Nullable x) {
        NSLog(@"%@", x);
    }];

代替通知

如监听键盘出现

    [[[NSNotificationCenter defaultCenter] rac_addObserverForName:UIKeyboardWillShowNotification object:nil] subscribeNext:^(NSNotification * _Nullable x) {
        NSLog(@"%@", x);
    }];