ReactiveCocoa中一些信号的转换及常用方法：

• 元组
  
  • 包装
  • 解析

//快速解析一个元组
    RACTupleUnpack(NSNumber *number1,NSNumber *number2) = tupe;
    NSLog(@"%@==>%@",number1,number2);

//快速包装一个元祖
    RACTuple *tupe = RACTuplePack(@1,@2);
    NSLog(@"%@",tupe);

• 解决强引用问题

@weakify(self);
    RACSignal *signal = [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {
        @strongify(self);
        self.age = 0;
        return nil;
    }];

• rac常用宏
  
  • 快速监听某个对象的某个属性改变
  • 为对象属性绑定信号源

//快速监听某个对象的某个属性改变
    [RACObserve(self,age) subscribeNext:^(id x) {
        NSLog(@"%@",x);
    }];

//为对象属性绑定信号源
     RAC(self.btn,titleLabel.text) = self.tfd.rac_textSignal;

• 监听文本内容改变

//监听文本内容改变
    [self.tfd.rac_textSignal subscribeNext:^(id x) {
        NSLog(@"%@",x);
    }];

• 自动订阅多个信号源

-(void)moreSignal
{
    RACSignal *signalA = [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {
        [subscriber sendNext:@1];
        return nil;
    }];

    RACSignal *signalB = [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {
        [subscriber sendNext:@2];
        return nil;
    }];

    //有几个信号方法要有几个参数，会自动订阅信号
    //必须同时存在
    [self rac_liftSelector:@selector(updateUIWithHot:new:) withSignalsFromArray:@[signalA,signalB]];
}

-(void)updateUIWithHot:(NSString *)hot new:(NSString *)new
{
    NSLog(@"hot ==>%@,new =>%@",hot,new);
}

• 监听通知相应事件

[[[NSNotificationCenter defaultCenter]rac_addObserverForName:UIKeyboardWillShowNotification object:nil] subscribeNext:^(id x) { }];

• KVO

[[self rac_valuesForKeyPath:@"age" observer:nil]subscribeNext:^(id x) {
        NSLog(@"xxx==>%@",x);
    }];

• event

[[_btn rac_signalForControlEvents:UIControlEventTouchUpInside]subscribeNext:^(id x) {
        NSLog(@"btn-->UIControlEventTouchUpInside");
    }];

• method

//将方法转换为信号（冷信号）
    [[self rac_signalForSelector:@selector(viewWillAppear:)] subscribeNext:^(id x) {
        NSLog(@"viewWillAppear");
    }];