NSTimer减少秒/毫秒的时间

Question

我正在开发一个QuiZ应用程序。它需要一个倒数计时器，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）。我想显示一个提醒，即时间！当时间到达00：00.00（mm：ss.SS）时。

我通过下面的链接

Stopwatch using NSTimer incorrectly includes paused time in display

Answer 1

这是一个简单的解决方案，您的问题。

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; 

} 

Answer 2

使用缩短定时器下面的代码显示的时间。

double dblRemainingTime=60; //1 minute 

if(dblRemainingTime >0) 
{ 
    dblRemainingTime -= 1; 
    int hours,minutes, seconds; 
    hours = dblRemainingTime/3600; 
    minutes = (dblRemainingTime - (hours*3600))/60; 
    seconds = fmod(dblRemainingTime, 60); 
    [lblRemainingTime setText:[NSString stringWithFormat:@"%02d:%02d",minutes, seconds]]; 
} 
else 
     alert('Time up buddy');