Can't endBackgroundTask: no background task exists with identifier, or it may have already been ended

Question

I am using background task to run the timer in the background to update the user\'s location. It\'s declared as:

UIBackgroundTaskIdentifier bgTask;
         


        

Answer 1

You need to set bgTask = UIBackgroundTaskInvalid

in two moments

1. In the expiration handler.
2. After finishing your task.

I believe you are missing any of those two moments and that is why you are getting that error.

See apple example code:

- (void)applicationDidEnterBackground:(UIApplication *)application
{
    bgTask = [application beginBackgroundTaskWithName:@"MyTask" expirationHandler:^{
        // Clean up any unfinished task business by marking where you
        // stopped or ending the task outright.
        [application endBackgroundTask:bgTask];
        bgTask = UIBackgroundTaskInvalid;
    }];

    // Start the long-running task and return immediately.
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{

        // Do the work associated with the task, preferably in chunks.

        [application endBackgroundTask:bgTask];
        bgTask = UIBackgroundTaskInvalid;
    });
}

link: https://developer.apple.com/documentation/backgroundtasks/bgtask?language=objc