iphone - NSTimers在后台 [英] iphone - NSTimers in background

问题描述

我正在开发一个必须在后台运行的应用程序。它是一个基于位置的应用程序，所以它一直运行，操作系统不会杀死它。

它应该每10秒发送一些信息（仅用于调试），我在后台设置了一个定时器。我在这个函数中设置一个断点，每10秒钟执行一次，这是永远不会被调用的，但如果我暂停应用程序，然后继续调用定时器，然后定时器每10秒钟执行一次，没有问题， / p>

我以为当我没有调试时，计时器将会执行，但是并不像我没有暂停调试一样。 p>

我的问题是为什么？定时器设置正确（我假设），因为它在暂停后工作，但不是。

任何想法？

我设置定时器的方式是：

  self.timer = [NSTimer scheduledTimerWithTimeInterval：10 target：self selector：@selector （doStuff）userInfo：nil重复：YES]; 
  

在我连接到webservice的函数中。

谢谢。

解决方案

我有一个类似的应用程序设计，被困在同一件事上。我在互联网上发现的地方是添加这种类型的语句 applicationDidEnterBackground：

  UIBackgroundTaskIdentifier locationUpdater = [[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler：^ {
 [[UIApplication sharedApplication] endBackgroundTask：locationUpdater]; 
 locationUpdater = UIBackgroundTaskInvalid; 
}]; 
  

这告诉我们你仍然有事情，而不是停止它。

我的定时器附加到此功能

  //这是一个包装方法适合所需的选择器签名
  - （void）timeIntervalEnded :( NSTimer *）timer {
 [self writeToLog：[NSString stringWithFormat：@Timer Ended On％@，[NSDate date]]] 
 [self startReadingLocation]; 
 [timer invalidate]; 
 timer = nil; 
} 
  

我在我的位置管理器委托方法中设置了计时器。

我感到你的痛苦。我发现这些东西是超级迷人的。这对我来说有用。我希望它有帮助。我发现在后台你不能做任何真正的限制。

Im developing an app that has to run in the background. It's a location based app, so it runs all the time, the OS doesn't kill it.

It should send some info every 10 secs(just for debugging), I set a timer once its in the background. I set a breakpoint in the function that should be executed every 10 secs, which is never called, but if I pause the app and then continue the timer is called, and then the timer is executed every 10 secs without problems, weird right?

I thought that the timer would be executing anyway when I wasn't debugging, but it isn't, same thing as if I didn't pause the debugging.

My question is WHY?? The timer is set correctly(I assume) since it works after pausing, but it's not.

Any ideas?

The way I set the timer is:

self.timer = [NSTimer scheduledTimerWithTimeInterval:10 target:self selector:@selector(doStuff) userInfo:nil repeats:YES];

And in the function I connect to a webservice.

Thanks.

解决方案

I have a similar app design and was stuck on the same thing. What I found somewhere on the internet is adding this type of statement applicationDidEnterBackground:

    UIBackgroundTaskIdentifier locationUpdater =[[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:^{
         [[UIApplication sharedApplication] endBackgroundTask:locationUpdater];
        locationUpdater=UIBackgroundTaskInvalid;
     } ]; 

This tells the os that you still have things going and not to stop it.

I have my timer attached to this function

 //this is a wrapper method to fit the required selector signature
- (void)timeIntervalEnded:(NSTimer*)timer {
     [self writeToLog:[NSString stringWithFormat:@"Timer Ended On %@",[NSDate date]]];
     [self startReadingLocation];
     [timer invalidate];
     timer=nil;
}

I set the timer in my my location manager delegate methods.

I feel your pain. I found that these things were super finicky. This is what worked for me. I hope it helps. I have found that there isn't any really restrictions in what you can do in the background.

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