获取验证码的定时器

-(void)verificationCode:(void(^)())blockYes blockNo:(void(^)(idtime))blockNo {

   __blockinttimeout=59;//倒计时时间
    dispatch_queue_t queue =dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT,0);
    dispatch_source_t _timer =dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER,0,0,queue);
    dispatch_source_set_timer(_timer,dispatch_walltime(NULL,0),1.0*NSEC_PER_SEC,0);//每秒执行
    dispatch_source_set_event_handler(_timer, ^{
        if(timeout<=0){//倒计时结束，关闭
            dispatch_source_cancel(_timer);
            dispatch_async(dispatch_get_main_queue(), ^{
                //设置界面的按钮显示根据自己需求设置
                blockYes();
            });
        }else{
            //int minutes = timeout / 60;
            int seconds = timeout %60;
           
            NSString *strTime = [NSStringstringWithFormat:@"%.2d", seconds];
            dispatch_async(dispatch_get_main_queue(), ^{
                //设置界面的按钮显示根据自己需求设置
                //NSLog(@"____%@",strTime);
                blockNo(strTime);
               
            });
            if([[[NSUserDefaultsstandardUserDefaults]objectForKey:@"StopTime"]isEqualToString:@"YES"]){
                timeout = 1;
            }
            timeout--;
        }
    });
    dispatch_resume(_timer);

}

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定时器使用的时候调用的方法：

[selfverificationCode:^{

       //倒计时结束的时候执行的语句

                }blockNo:^(idtime) {

       //计时过程中执行的地方。time就是倒计时的数值

                }];