Question

我尝试使用此代码，但我收到错误“timeLabel undeclared”

我如何声明timeLabel。感谢..

提前感谢...尝试让计时器工作，但似乎代码有一些错误..

//In Header
int timeSec = 0;
int timeMin = 0;
NSTimer *timer;

//Call This to Start timer, will tick every second
-(void) StartTimer
{
     timer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(timerTick:) userInfo:nil repeats:YES];
     [[NSRunLoop currentRunLoop] addTimer:timer forMode:NSDefaultRunLoopMode];
}

//Event called every time the NSTimer ticks.
- (void)timerTick:(NSTimer *)timer
{
     timeSec++;
     if (timeSec == 60)
     {
        timeSec = 0;
        timeMin++;
     }
     //Format the string 00:00
     NSString* timeNow = [NSString stringWithFormat:@"%02d:%02d", timeMin, timeSec];
     //Display on your label
     [timeLabel setStringValue:timeNow];
}

//Call this to stop the timer event(could use as a 'Pause' or 'Reset')
- (void) StopTimer
{
    [timer invalidate];
    timeSec = 0; 
    timeMin = 0;
     //Since we reset here, and timerTick won't update your label again, we need to refresh it again.
     //Format the string in 00:00
     NSString* timeNow = [NSString stringWithFormat:@"%02d:%02d", timeMin, timeSec];
     //Display on your label
     [timeLabel setStringValue:timeNow];
}

Answer 1

In .h File write 
NSTimer *timer

and make it as property
@property(nonatomic,retain)NSTimer*timer 


and in .m file
-(void)yourFunction
{

    [timer invalidate];
    timer = nil;
    timer = [NSTimer scheduledTimerWithTimeInterval: 1.5 target: self selector: @selector(yourFunctionYouWantToCall) userInfo: nil repeats: YES];
}
-(void)YourFunctionYouWantToCall
{

[timer invalidate];
    timer = nil;

////Your Code her////
}

Answer 2

如果编译器声明timeLabel未声明，您可能忘记在类的实例变量中声明它。查看.h文件，看看你是否有timeLabel的声明。如果是，请发布您的课程'@interface部分，以便我们可以看到正在发生的事情。

计时器在xcode错误

2 个答案: