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我有一個秒錶，可以在我的應用程序上正常運行，但是當我點擊後退按鈕轉到另一個視圖時停止。即使用戶正在查看其他頁面，我也希望秒錶能夠繼續運行。NSTimer秒錶
我該如何做到這一點？
確定添加的代碼
代碼：
.H
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;
.M
- (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];
}
哪個對象擁有NSTimer？ – bneely 2012-02-12 23:07:02