Question

在我的应用程序中使用NSTimer，我必须显示倒数计时器，初始时间等于100秒。它显示99，然后98..96..94..92 ... 86等等。但我希望每一秒出现。这是我的代码......

   -(void)updateTimerLabel{
   if (timeRemaining>0 ) {



    timeRemaining=timeRemaining-1.0;
    timerLabel.text=[NSString stringWithFormat:@"%.0f", timeRemaining];


    countdownTimer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(updateTimerLabel) userInfo:nil repeats:YES];
    }
}

Answer 1

每次调用方法时，您实际上都在重新创建计时器。

你应该尝试将它留在外面并保留它直到你完成它。

@interface SomeClass

NSTimer * aTimer;

@end

@implementation

- (void)createTimer {
    aTimer = [[NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(updateTimerLabel) userInfo:nil repeats:YES] retain];
}

- (void)updateTimerLabel {
    // do timer updates here

    // call [aTimer release]
    // and [aTimer invalidate]
    // aTimer = nil;
    // when you're done
}

@end

Answer 2

尝试以下代码

int i =100;

-(void)viewDidLoad
{
[super viewDidLoad];
[NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(theActionMethod) userInfo:nil repeats:YES];  

}

-(void)theActionMethod
{
   if(i > 0)
   {
      NSString *str = [NSString stringWithFormat:@"%d",i];
      lbl.text = str;
   }
   i--;
}

Answer 3

您已在方法外调用updateTimerLabel。例如： - （void）viewDidLoad {timeRemaining = 100.0; [self updateTimerLabel]; countdownTimer = [NSTimer scheduledTimerWithTimeInterval：1.0 target：self selector：@selector（updateTimerLabel）userInfo：nil repeats：YES];}

- （无效）updateTimerLabel {if（timeRemaining＆gt; 0） {timeRemaining = timeRemaining-1.0; NSLog（@“％@”，[NSString stringWithFormat：@“％。0f”，timeRemaining]）;}}

无法让NSTimer工作

3 个答案: