How to use beginBackgroundTaskWithExpirationHandler for already running task in iOS

Question

In my app, I am uploading images to server from iPhone. While sync if user press home button, App will close.

I want app must be running in background till sync fini

Answer 1

I used below code for background task handler:

__block UIBackgroundTaskIdentifier backgroundTaskIdentifier = [[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:^{

    NSLog(@"Background Time:%f",[[UIApplication sharedApplication] backgroundTimeRemaining]);

    [[UIApplication sharedApplication] endBackgroundTask:backgroundTaskIdentifier];

    backgroundTaskIdentifier = UIBackgroundTaskInvalid;
}];