Objective-c 获取数字然后每秒倒数1的方法

发布于 2024-10-15 23:25:33 字数 855 浏览 7 评论 0原文

我需要一点帮助，我有一个获取诸如 50 之类的值的方法，然后将该值分配给 trackDuration，因此 NSNumber *trackDuration = 50，我希望该方法每秒从 trackDuration 的值减去 1 并更新标签，标签称为持续时间。

这是我到目前为止所拥有的；

- (void) countDown {
iTunesApplication *iTunes = [SBApplication applicationWithBundleIdentifier:@"com.apple.iTunes"];

NSNumber *trackDuration = [NSNumber numberWithDouble:[[iTunes currentTrack] duration]];
while (trackDuration > 0) {
    trackDuration - 1;
    int inputSeconds = [trackDuration intValue];
    int hours =  inputSeconds / 3600;
    int minutes = ( inputSeconds - hours * 3600 ) / 60; 
    int seconds = inputSeconds - hours * 3600 - minutes * 60; 
    NSString *trackDurationString = [NSString stringWithFormat:@"%.2d:%.2d:%.2d", hours, minutes, seconds];
    [duration setStringValue:trackDurationString];
    sleep(1);
}}

任何帮助将不胜感激，提前感谢，萨米。

原文

i need a little help i have a method which gets value such as 50, it then assigns that value to trackDuration, so NSNumber *trackDuration = 50, i want the method to every second minus 1 from the value of trackDuration and update a label, the label being called duration.

Here's what i have so far;

- (void) countDown {
iTunesApplication *iTunes = [SBApplication applicationWithBundleIdentifier:@"com.apple.iTunes"];

NSNumber *trackDuration = [NSNumber numberWithDouble:[[iTunes currentTrack] duration]];
while (trackDuration > 0) {
    trackDuration - 1;
    int inputSeconds = [trackDuration intValue];
    int hours =  inputSeconds / 3600;
    int minutes = ( inputSeconds - hours * 3600 ) / 60; 
    int seconds = inputSeconds - hours * 3600 - minutes * 60; 
    NSString *trackDurationString = [NSString stringWithFormat:@"%.2d:%.2d:%.2d", hours, minutes, seconds];
    [duration setStringValue:trackDurationString];
    sleep(1);
}}

Any help would be much appreciated, thanks in advanced, Sami.

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不即不离 2024-10-22 23:25:33

这将阻塞主线程，并且您没有分配值 trackDuration，因此它将始终保持 50

trackDuration -1;

应该是：

trackDuration--; // or trackDuration -= 1;

另外我会这样做：

- (void)startCountDown
{
    [NSTimer scheduledTimerWithInterval:1.0f target:self selector:@selector(timerHit:) userInfo:nil repeats:YES];
}
- (void)timerHit:(NSTimer *)p_timer
{
  if( trackDuration <= 1 && [p_timer isValid] )
     [p_timer invalidate];
 // track duration is an instance variable
 trackDuration--;
 // update LABEL
}

NSTimer 需要 iOS 2.x 或更高版本

This will block the main thread, and you are not assigning the value trackDuration, so it will always stay 50

trackDuration -1;

Should be:

trackDuration--; // or trackDuration -= 1;

Also I would do it like this:

- (void)startCountDown
{
    [NSTimer scheduledTimerWithInterval:1.0f target:self selector:@selector(timerHit:) userInfo:nil repeats:YES];
}
- (void)timerHit:(NSTimer *)p_timer
{
  if( trackDuration <= 1 && [p_timer isValid] )
     [p_timer invalidate];
 // track duration is an instance variable
 trackDuration--;
 // update LABEL
}

iOS 2.x or higher is required for NSTimer

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