Question

My iOS app doesn’t run in background. When home button is hit the app will terminate.

Below is my code

- (void)applicationDidEnterBackground:(UIApplication *)application 
{
  double sleepTime = [[UIApplication sharedApplication] backgroundTimeRemaining] - 1;

  [self performTaskforTime:sleepTime];
}

If the application is relaunched in no time, the New instance of the app will killed with the error :

Exception Type: 00000020 Exception Codes: 0x8badf00d Highlighted
Thread: 0

Application Specific Information: My_App failed to launch in time

I can’t reduce the sleep time. Is there any solution for this?

Answer 1

You need to return from - (void)applicationDidEnterBackground:(UIApplication *)application, do something like this:

- (void)applicationDidEnterBackground:(UIApplication *)application 
{
  UIBackgroundTaskIdentifier btid = [[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:NULL];

  double sleepTime = [[UIApplication sharedApplication] backgroundTimeRemaining] - 1;

  dispatch_async(/* background queue */, ^{
    [self performTaskforTime:sleepTime];
    [[UIApplication sharedApplication] endBackgroundTask:btid];
  }
}

You don’t want to block the main queue with a long running task as you won’t be able to service the UI otherwise. Your application is busy with -performTaskforTime: and thus can’t launch in time.