__block int time = ;

        __block UIButton *verifybutton = _GetverificationBtn;

        verifybutton.enabled = NO;

        dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, );

        dispatch_source_t _timer = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, , ,queue);

        dispatch_source_set_timer(_timer,dispatch_walltime(NULL, ),1.0*NSEC_PER_SEC, ); //每秒执行

        dispatch_source_set_event_handler(_timer, ^{

            if(time<=){ //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

                    verifybutton.backgroundColor = [UIColor colorWithHexString:@"FC740A"];

                    [verifybutton setTitle:@"获取验证码" forState:UIControlStateNormal];

                    verifybutton.enabled = YES;

                });

            }else{

                dispatch_async(dispatch_get_main_queue(), ^{

                    //设置界面的按钮显示 根据自己需求设置

                    verifybutton.backgroundColor = [UIColor grayColor];

                    NSString *strTime = [NSString stringWithFormat:@"获取验证码(%d)",time];

                    [verifybutton setTitle:strTime forState:UIControlStateNormal];

                    verifybutton.titleLabel.textColor = [UIColor whiteColor];

                });

                time--;

            }

        });

        dispatch_resume(_timer);