（五）、iOS RAC - 定时器

@property (nonatomic, strong, readwrite) UIButton *codeBtn;
@property (nonatomic, assign, readwrite) int timer;
@property (nonatomic, strong, readwrite) RACDisposable *disposable;

- (void)viewDidLoad {
 //按钮点击
@weakify(self)
[[self.codeBtn rac_signalForControlEvents:UIControlEventTouchUpInside] subscribeNext:^(__kindof UIControl * _Nullable x) {
    @strongify(self)
    
    NSLog(@"123123123");
   
    x.enabled = false;
    self.timer = 10;
    
    //这个就是RAC中的GCD
    
    /**
     [[RACSignal interval:1.0 onScheduler:[RACScheduler mainThreadScheduler]]
     @param 1. 在这个方法里面第一步 是 创建了一个RACSignal 当外部订阅的时候就会调用scheduler的after...方法，在返回的回调中发送数据
     @param 2. after... 内部就是调用的GCD的定时器 定时器的block就是外界传进来的block 创建一个RACDisposable，调用disposable方法等时候就会进入创建对象的block，把定时器释放掉
     @param 3.@weakify(self)，@strongify(self) 解决循环引用，且必须配套使用；
     */
    self.disposable = [[RACSignal interval:1.0 onScheduler:[RACScheduler mainThreadScheduler]] subscribeNext:^(NSDate * _Nullable x) {
        self.timer --;
        NSString *title = self.timer > 0 ? [NSString stringWithFormat:@"%d",self.timer] : @"发送验证码";
        [self.codeBtn setTitle:title forState:UIControlStateNormal | UIControlStateDisabled];
        self.codeBtn.enabled = (self.timer == 0 ) ? true : false;
        if (self.timer == 0) {
            [self.disposable dispose];
        }
    }];
}];
}

- (UIButton *)codeBtn {
if (!_codeBtn) {
    _codeBtn = [UIButton buttonWithType:UIButtonTypeCustom];
    _codeBtn.backgroundColor = [UIColor redColor];
    [_codeBtn setTitleColor:[UIColor greenColor] forState:UIControlStateNormal];
    [_codeBtn setTitle:@"发送验证码" forState:UIControlStateNormal];
    _codeBtn.frame  = CGRectMake(0, 0, 200, 200);
    _codeBtn.center = self.view.center;
}
return _codeBtn;
}