ios开发之倒计时实现的方法

方法1:使用GCD来实现
//倒计时
-(void)countdown
{
    __block int timeout=60; //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
                [_verificationButton setTitle:@"发送验证码" forState:UIControlStateNormal];
                _verificationButton.backgroundColor = [UIColor colorWithHexString:@"ec611e"];
                _verificationButton.userInteractionEnabled = YES;
            });
        }else{
            //            int minutes = timeout / 60;
            int seconds = timeout % 61;
            
            NSString *strTime = [NSString stringWithFormat:@"%.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);
                [_verificationButton setTitle:[NSString stringWithFormat:@"%@S",strTime] forState:UIControlStateNormal];
                _verificationButton.userInteractionEnabled = NO;
                _verificationButton.backgroundColor = [UIColor colorWithRed:203/255.0 green:203/255.0 blue:203/255.0 alpha:1];
                
            });
            timeout--;
            
        }
    });
    dispatch_resume(_timer);
}

方法1:使用NSTimer来实现

        主要使用的是NSTimer的scheduledTimerWithTimeInterval方法来每1秒执行一次timeFireMethod函数,timeFireMethod进行倒计时的一些操作,完成时把timer给invalidate掉就可以了,代码如下:

secondsCountDown = 60;//60秒倒计时  
 countDownTimer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(timeFireMethod) userInfo:nil repeats:YES];  
-(void)timeFireMethod{  
    secondsCountDown--;  
    if(secondsCountDown==0){  
      [countDownTimer invalidate];  
    }  
}


你可能感兴趣的:(ios开发)