替代NSTimer的block计时器！！

话不多说上代码：LIST

-(void)startTime{

    timeout_int=0;

    dispatch_queue_t queue_global =dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);

    dispatch_source_t _timer = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0,0,queue_global);

    dispatch_source_set_timer(_timer,dispatch_walltime(NULL, 0),1.0*NSEC_PER_SEC, 0);

    dispatch_source_set_event_handler(_timer, ^{

        __weak ViewController *weakself =self ;

        if(timeout_int>10){ //倒计时结束，关闭

            dispatch_source_cancel(_timer);

            dispatch_async(dispatch_get_main_queue(), ^{

               weakself.numberLabel.text = @"结束";

            });

        }else{

            //            int minutes = timeout_int / 60;

            int seconds = timeout_int % 61;

            NSString *strTime = [NSString stringWithFormat:@"%.2d", seconds];

           dispatch_async(dispatch_get_main_queue(), ^{

                //设置界面的按钮显示

                weakself.numberLabel.text = strTime;

            });

            timeout_int++;

              }

    });

    dispatch_resume(_timer);

}

转载于:https://my.oschina.net/u/2361170/blog/466093