View 如何不在Xcode中释放视图

您好，我有一个秒表视图，当用户单击后退按钮转到另一个视图时，秒表将停止。我有人告诉我这是因为它被释放了

我想让秒表继续走

那么，我如何取消发布或不允许发布它呢

这是我的代码

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我会尝试不同的方法，而不是更改视图控制器的行为：

通过将计时器功能移动到单独的对象中，可以使计时器独立于视图控制器。这样，计时器对象与视图控制器对象具有不同的生命周期。例如，您可以在应用程序委托中创建（并释放）计时器对象，创建对它的引用并在视图控制器中访问它

UILabel *stopWatchLabel;

NSTimer *stopWatchTimer; // Store the timer that fires after a certain time
NSDate *startDate; // Stores the date of the click on the start button

@property (nonatomic, retain) IBOutlet UILabel *stopWatchLabel;

- (IBAction)onStartPressed:(id)sender;
- (IBAction)onStopPressed:(id)sender;

- (void)viewDidUnload
{
[self setStopWatchLabel:nil];
[super viewDidUnload];
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
}


- (void)updateTimer
{
NSDate *currentDate = [NSDate date];
NSTimeInterval timeInterval = [currentDate timeIntervalSinceDate:startDate];
NSDate *timerDate = [NSDate dateWithTimeIntervalSince1970:timeInterval];

NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"HH:mm:ss.SSS"];
[dateFormatter setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0.0]];
NSString *timeString=[dateFormatter stringFromDate:timerDate];
stopWatchLabel.text = timeString;
}

- (IBAction)onStartPressed:(id)sender {
startDate = [NSDate date];

// Create the stop watch timer that fires every 10 ms
stopWatchTimer = [NSTimer scheduledTimerWithTimeInterval:1.0/10.0
                                                  target:self
                                                selector:@selector(updateTimer)
                                                userInfo:nil
                                                 repeats:YES];
}

- (IBAction)onStopPressed:(id)sender {
[stopWatchTimer invalidate];
stopWatchTimer = nil;
[self updateTimer]; 
}