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 til

Answer 1

In one of my apps, I was loading huge amount of data. I definitely can't expect the user to keep the app in foreground until the data is downloaded. I just use following code to get the data downloading while app is in background. Its working properly :-)
Please go through following steps:

1) use following line in header file of ViewController

   @property (nonatomic) UIBackgroundTaskIdentifier backgroundTask;

synthesis it in .m file.

2) in ViewDidLoad assign UIBackgroundTaskIdentifier like:

   self.backgroundTask = UIBackgroundTaskInvalid;

3) Use following line of code, here I am just keeping on getDataFromServer method inside beginBackgroundTaskWithExpirationHandler: block.

        self.backgroundTask = [[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:^{

        [[UIApplication sharedApplication] endBackgroundTask:self.backgroundTask];
        self.backgroundTask = UIBackgroundTaskInvalid;
    }];

    /* Here your downloading Code, let say getDataFromServer method */

    [self getDataFromServer]; // Its dummy method

    /* Your downloading Code End Here */

    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{

        [[UIApplication sharedApplication] endBackgroundTask:self.backgroundTask];
        self.backgroundTask = UIBackgroundTaskInvalid;
    });

4) If you want to check time remaining to download data in background, include following line in applicationDidEnterBackground:(UIApplication *)application delegate method of AppDelegate:

      NSLog(@"Background time remaining = %.1f seconds", [UIApplication sharedApplication].backgroundTimeRemaining);