iOS倒计时

pragma mark ---获取验证码

-(void)getCodeButtonClick:(UIButton *)sender{
[self.view endEditing:YES];
if ([self.phone.text isEqualToString:@""]) {
    [self showHint:@"手机号不能为空！"];
    return;
}else if (self.phone.text.length != 11){
    [self showHint:@"手机号格式不正确"];
    return;
}else{
    [self startTimeWithButton:sender withTime:5];
    
}
}

/**
获取验证码，倒计时
@param sender 获取验证码的按钮
@param time 倒计的时间
*/

-(void)startTimeWithButton:(UIButton *)sender withTime:(int)time{

sender.userInteractionEnabled = NO;//关闭交互
sender.backgroundColor = [UIColor whiteColor];
[sender setTitleColor:HRColor(67, 67, 67, 1) forState:UIControlStateNormal];

__block int timeout = time;
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
        dispatch_source_cancel(_timer);
        dispatch_async(dispatch_get_main_queue(), ^{
            //倒计时结束时调用
            [sender setTitle:@"重新获取验证码" forState:UIControlStateNormal];
            sender.userInteractionEnabled = YES;//打开交互
            [sender setTitleColor:[UIColor colorWithHexString:@"e4e4e4" alpha:1] forState:UIControlStateNormal];
        });
    }else{//倒计时未结束
        int seconds = timeout %(time+1);
        NSString *strTime = [NSString stringWithFormat:@"%d",seconds];
        dispatch_async(dispatch_get_main_queue(), ^{
            [sender setTitle:[NSString stringWithFormat:@"%@秒",strTime] forState:UIControlStateNormal];
        });
        timeout--;
    }
});
dispatch_resume(_timer);
}