backgroundTimeRemaining的这个大数字是多少？

我刚刚进入iOS编程,并且正在努力解决很多问题.

我正在尝试实现一小段代码来获取当前位置并在后台将其发送到服务器.当我打电话时beginBackgroundTaskWithExpirationHandler,我发现backgroundTimeRemaining财产的回报如此之大.查看代码下面的日志.

if (self.backgroundTask == UIBackgroundTaskInvalid) {
        NSLog(@"***** startBackground work");

        UIApplication *app = [UIApplication sharedApplication];

        self.backgroundTask = [app beginBackgroundTaskWithExpirationHandler:^{
            NSLog(@"Background handler called. Not running background tasks anymore.");
            [app endBackgroundTask:self.backgroundTask];
            self.backgroundTask = UIBackgroundTaskInvalid;
        }];

        DebugLog(@"====>backgroundTimeRemaining:%.1f seconds", app.backgroundTimeRemaining);
        if (timer == nil) {
            timer = [NSTimer scheduledTimerWithTimeInterval:10 * 60
                                                     target:self
                                                   selector: @selector(timerFired:)
                                                   userInfo:nil
                                                    repeats:YES];
        }
    }

日志:

2013-11-29 09:23:14.852 JeeneeLocatorService[1666:70b]  ====>backgroundTimeRemaining:179769313486231570814527423731704356798070567525844996598917476803157260780028538760589558632766878171540458953514382464234321326889464182768467546703537516986049910576551282076245490090389328944075868508455133942304583236903222948165808559332123348274797826204144723168738177180919299881250404026184124858368.0 seconds

它看起来不正常,我已经从iOS开发者库网站iOS上读取了大约10分钟,即使我打电话 beginBackgroundTaskWithExpirationHandler做很长时间的后台任务.

我正在使用XCode5中的iOS7模拟器进行测试.我是否可以将大量时间用于后台工作.你的回答将非常感激.

编辑:得到答案后,我将剩余时间显示代码移动到timerFired:方法.

- (void)timerFired:(NSTimer *)timer {
        DebugLog(@"***** Timer fired *****");

        UIApplication *app = [UIApplication sharedApplication];
        DebugLog(@"====>backgroundTimeRemaining:%.1f seconds", app.backgroundTimeRemaining);
 }

但是,每当调用timerFired:方法时,它仍然会给我相同的时间.这不适用于模拟器吗？