iOS获取倒计时按钮

//验证码时间

@property (nonatomic,strong)NSTimer  *timer;

//开始计时

_timer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(Countdown) userInfo:nil repeats:YES];

//倒计时

- (void)Countdown

{

static NSInteger time = 59;

self.captchaButton.userInteractionEnabled = NO;

self.captchaButton.alpha = 0.6;

if (time > -1) {

NSString *number = [NSString stringWithFormat:@"%ld",(long)time];

[_captchaButton setTitle:number forState:UIControlStateNormal];

} else {

[_captchaButton setTitle:@"获取" forState:UIControlStateNormal];

self.captchaButton.userInteractionEnabled = YES;

self.captchaButton.alpha = 1;

[_timer invalidate];//停止计时器

_timer = nil;//重置计时器

time = 60;

}

time --;

}

[timer setFireDate:[NSDate date]]; //继续。

[timer setFireDate:[NSDate distantPast]];//开启

[timer setFireDate:[NSDate distantFuture]];//暂停