NSTimer减少秒/毫秒的时间 [英] NSTimer Decrease the time by seconds/milliseconds

问题描述

我正在开发QuiZ应用程序。它需要倒数计时器，因为我想在75：00.00（mm：ss.SS）启动一个计时器，并通过减少1毫秒将其减少到00：00.00（mm：ss.SS）。我想显示Time Up的警报！当时间到达00：00.00（mm：ss.SS）。

I am developing a QuiZ app. It needs a countdown timer, In that I want to start a timer at 75:00.00 (mm:ss.SS) and decrease it to 00:00.00 (mm:ss.SS) by reducing 1 millisecond. I want to display an alert that Time UP! when time reaches to 00:00.00 (mm:ss.SS).

我通过以下链接显示时间

I am displaying the time by following below link

使用NSTimer的秒表错误地包括显示的暂停时间

推荐答案

以下是您问题的简单解决方案。

Here is a simple solutions to your problem.

声明

@interface ViewController : UIViewController
{
    IBOutlet UILabel * result;      
    NSTimer * timer;                
    int currentTime;
}

- (void)populateLabelwithTime:(int)milliseconds;
-(IBAction)start;
-(IBAction)pause;
@end

定义

- (void)viewDidLoad
{
    [super viewDidLoad];

    currentTime = 270000000; // Since 75 hours = 270000000 milli seconds


}

-(IBAction)start{
   timer = [NSTimer scheduledTimerWithTimeInterval:.01 target:self selector:@selector(updateTimer:) userInfo:nil repeats:YES];

}
-(IBAction)pause{
    [timer invalidate];

}
- (void)updateTimer:(NSTimer *)timer {
    currentTime -= 10 ;
    [self populateLabelwithTime:currentTime];
     }
- (void)populateLabelwithTime:(int)milliseconds {
    int seconds = milliseconds/1000;
    int minutes = seconds / 60;
    int hours = minutes / 60;

    seconds -= minutes * 60;
    minutes -= hours * 60;

   NSString * result1 = [NSString stringWithFormat:@"%@%02dh:%02dm:%02ds:%02dms", (milliseconds<0?@"-":@""), hours, minutes, seconds,milliseconds%1000];
    result.text = result1;

}

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