每次页面加载时，计时器的减量会有所不同 [英] Timer decrement gets varied for each page load

问题描述

我的项目有一个计时器，每次减少1秒.但是，如果计数器第二次开始工作，则递减2秒，第三次减少3秒，以此类推.我应该怎么做才能始终使1秒递减?

I have a timer for my project, each time it decrements by 1 second. But if the counter starts working for the second time it gets decremented by 2 seconds and for the third time by 3 seconds etc. what should I do to get 1 sec decrement for all the time?

-(void)viewDidAppear:(BOOL)animated { 

    count=15; //timer set as 15 seconds 
    [NSTimer scheduledTimerWithTimeInterval:1.0f target:self selector:@selector(updateCounter:)userInfo:nil repeats:YES]; //for decrementing timer
}

- (void)updateCounter:(NSTimer *)theTimer { 
    count -= 1; 
    NSString *s = [[NSString alloc] initWithFormat:@"%d", count]; 
    if(count==0) // alert for time expiry 
    { 
       alert = [[UIAlertView alloc] initWithTitle:@"Time Out!!" message:@"Your time is expired." delegate:self cancelButtonTitle:@"Ok" otherButtonTitles:nil]; 
       [alert show]; 
       self.timer.hidden=YES; 
       [self dismissModalViewControllerAnimated:YES]; 
    } 

    else { 
      self.timer.text = s;
    } 

    [s release]; 
} 

推荐答案

根据您发布的内容，您正在创建多个计时器，而不是停止其中的任何一个.因此，经过3次之后，您每秒就有3个计时器触发.

From what you've posted, you're creating multiple timers and not stopping any of them. So after 3 times, you have 3 timers firing each second.

至少，当计时器为零时，您要使其无效:

At a minimum, when the timer hits zero you want to invalidate it:

[theTimer invalidate]

但是您可能还需要考虑保留您创建的计时器(以@property表示)，以便如果用户在计数器实际为零之前以其他方式离开此视图，则可以使计时器无效并释放它.

But you may also want to consider holding onto the timer you create (in a @property) so that you can invalidate and release it if the user leaves this view some other way before your counter actually goes to zero.

希望有帮助.

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