iOS Background downloads when the app is not active

Question

When my app is initially downloaded, the user needs to download a large file something like 200MB (upper limit). I definitely can't expect the user to keep the app open till this file is downloaded. So he/she might close the app & the app will go into background.

How can I continue to download the file in this scenario? Is this even possible in iOS?

Answer 1

Add below in your - (void)applicationDidEnterBackground:(UIApplication *)application

UIApplication  *app = [UIApplication sharedApplication]; UIBackgroundTaskIdentifier bgTask;  bgTask = [app beginBackgroundTaskWithExpirationHandler:^{          [app endBackgroundTask:bgTask];  }]; 

and you are good to go... I have this in one of my published download manager app

This will work just fine. You can also check how much time you have, since apple only enable 10 minutes background tasks. Use:

NSTimeInterval ti = [[UIApplication sharedApplication]backgroundTimeRemaining]; NSLog(@"backgroundTimeRemaining: %f", ti); // just for debug 

Answer 2

It is possible to start a background task when you begin the download:

Apps that are transitioning to the background can request an extra amount of time to finish any important last-minute tasks.

Executing a Finite-Length Task in the Background

However, such a task is limited to an undefined amount of execution time by the system. However, a 200Mb file download may be too large a task in this case.