参考资料：

• ReactiveCocoa源码（OC版）

• Swift 版 or ReactiveSwift

• MVVMReactiveCocoaDemo介绍

常见用法

1. rac_signalForControlEvents监听事件，替换addTarget监听

    [[self.myButton rac_signalForControlEvents:UIControlEventTouchUpInside] subscribeNext:^(id x) {@strongify(self);//改变属性 触发KVOself.userModel.userName=@"cnblogs";//发送通知 触发通知监听[[NSNotificationCenter defaultCenter] postNotificationName:MPTNotificationName object:nil];NSLog(@"rac_signalForControlEvents监听事件 - ");}];
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2. rac_textSignal 监听文本框的文字改变

    [[self.myTextField rac_textSignal] subscribeNext:^(id x) {NSLog(@"rac_textSignal当前输入:%@",x);}];//distinctUntilChanged 相同就不会再响应  takeUntil:(RACSignal *):获取信号直到某个信号执行完成[[[[self.myTextField rac_textSignal] distinctUntilChanged] takeUntil:self.rac_willDeallocSignal] subscribeNext:^(id x) {NSLog(@"rac_textSignal-distinctUntilChanged当前输入:%@",x);}];
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3. rac_valuesAndChangesForKeyPath KVO监听

    [[self.userModel rac_valuesAndChangesForKeyPath:@"userName"
options:NSKeyValueObservingOptionNew observer:nil] subscribeNext:^(id x) {NSLog(@"userName now value：%@",x[0]);}];
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4. 监听通知

    [[[[NSNotificationCenter defaultCenter] rac_addObserverForName:MPTNotificationName object:nil] takeUntil:self.rac_willDeallocSignal] subscribeNext:^(id x) {NSLog(@"收到通知了");}];
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5. 替换代理方法的实现 rac_signalForSelector

    UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"RAC" message:@"RAC TEST" delegate:self cancelButtonTitle:@"cancel" otherButtonTitles:@"other", nil];[[self rac_signalForSelector:@selector(alertView:clickedButtonAtIndex:) fromProtocol:@protocol(UIAlertViewDelegate)] subscribeNext:^(RACTuple *tuple) {NSLog(@"tuple.first:%@",tuple.first);NSLog(@"tuple.second:%@",tuple.second);NSLog(@"tuple.third:%@",tuple.third);//tuple.first UIAlertView当前对象//tuple.second索引值}];[alertView show];//   [[self rac_signalForSelector:@selector(alertView:clickedButtonAtIndex:)] subscribeNext:^(id x) {
//
//  }];//UIAlertView 还有更简便的 上面只是为了演示rac_signalForSelector  下面的X就是索引值//如果使用此方法rac_signalForSelector 不会再执行了。因为rac_buttonClickedSignal内部已经订阅了rac_signalForSelector方法[[alertView rac_buttonClickedSignal] subscribeNext:^(id x) {NSLog(@"index %@",x);}];
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6. 处理多个请求，都返回结果的时候，统一做处理.

rac_liftSelectorRACSignal *request1 = [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {// 发送请求1[subscriber sendNext:@"发送请求1"];return nil;}];RACSignal *request2 = [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {// 发送请求2[subscriber sendNext:@"发送请求2"];return nil;}];// 使用注意：几个信号，参数一的方法就几个参数，每个参数对应信号发出的数据。[self rac_liftSelector:@selector(updateUIWithR1:r2:) withSignalsFromArray:@[request1,request2]];复制代码

更新UI

- (void)updateUIWithR1:(id)data r2:(id)data1
{NSLog(@"更新UI%@  %@",data,data1);
}
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队列

   //then用法//用于连接两个信号，当第一个信号完成，才会连接then返回的信号RACSignal *thenSignal=[aSignal then:^RACSignal *{return bSignal;}];[thenSignal subscribeNext:^(id x) {NSLog(@"thenSignal的值：%@",x);}];//输出  thenSignal的值：7   thenSignal的值：9   bSignal清理了  aSignal清理了//then实例[[[[RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {NSLog(@"第一步");[subscriber sendCompleted];//向订阅者发送完成信号，否者一直处于执行中return nil;}] then:^RACSignal *{return [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {NSLog(@"第二步");[subscriber sendCompleted];return nil;}];}] then:^RACSignal *{return [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {NSLog(@"第三步");[subscriber sendCompleted];return nil;}];}] subscribeCompleted:^{NSLog(@"完成");}];//输出：第一步   第二步  第三步//说明：then的用法要跟上面这样使用，它会在RACSignal里面就执行
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• doNext doCompleted执行时间 doNext: 执行Next之前，会先执行这个Block doCompleted: 执行sendCompleted之前，会先执行这个Block

[[[[RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {[subscriber sendNext:@"执行sendNext"];NSLog(@"执行sendNext");[subscriber sendCompleted];return nil;}] doNext:^(id x) {NSLog(@"执行doNext");}] doCompleted:^{NSLog(@"执行doCompleted");}] subscribeNext:^(id x) {NSLog(@"执行subscribeNext");
}];//    输出
//    执行doNext
//    执行subscribeNext
//    执行sendNext
//    执行doCompleted复制代码