秒表显示问题

时间:2011-05-13 23:32:19

标签: objective-c ios nsstring nstimer stopwatch

我编译了以下代码,没有明显的运行时错误;但是,当我运行时,显示屏在00:00:01冻结。如果我只显示seconds属性,它可以工作。有没有人看到我在这段代码中遗漏的明显疏忽?我知道启动按钮可能存在内存泄漏,但我最终会解决这个问题。

提前致谢。

#import "StopwatchViewController.h"

@implementation StopwatchViewController

- (IBAction)start{

    //creates and fires timer every second
    myTimer = [[NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(showTime) userInfo:nil repeats:YES]retain];
}
- (IBAction)stop{
    [myTimer invalidate];
    myTimer = nil;
}

- (IBAction)reset{

    [myTimer invalidate];
    time.text = @"00:00:00";
}

(void)showTime{

    int currentTime = [time.text intValue];

    int new = currentTime +1;

    int secs  = new;
    int mins  = (secs/60) % 60;
    int hours = (mins/60);

    time.text = [NSString stringWithFormat:@"%.2d:%.2d:%.2d",hours, mins, secs];
}

2 个答案:

答案 0 :(得分:3)

你从

得到0
int currentTime = [time.text intValue];

因为text中的字符串:

@"00:00:00"

无法转换为int,因此每次计时器触发时,都会添加1到0并获得1,然后显示。无论如何,数学将是不准确的,因为分钟和秒是“基数为60”* - 您需要执行与分离小时/分钟/秒相关的数学运算的反向,以便再次获得总秒数。您可以将currentTime设为ivar,并保留其中的总秒数。


*这不是真正的所谓;我确定有一个特定的词。

答案 1 :(得分:2)

- (IBAction)start{

    currentTime = 0;

    //creates and fires timer every second
    myTimer = [[NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(showTime) userInfo:nil repeats:YES]retain];
}

- (IBAction)stop{
    [myTimer invalidate];
    myTimer = nil;
}

- (IBAction)reset{

    [myTimer invalidate];
    time.text = @"00:00:00";
}

- (void)showTime{

    currentTime++;

    int secs = currentTime % 60;
    int mins = (currentTime / 60) % 60;
    int hour = (currentTime / 3600);


    time.text = [NSString stringWithFormat:@"%.2d:%.2d:%.2d",hour, mins, secs];

}