App restarts when woken from background

Question

G\'day iOS Guru\'s,

I have searched extensively for an answer, but can\'t find one (I bet the first response to my question will be to another similar question, but I ca

Answer 1

iOS can, and will, terminate your app while it's in the background if it needs additional resources to carry out whatever's going on in the foreground.

You need to ensure that your data is saved/archived when your app is terminated, and unpacked when re-launched so as to go back to where the user last was. The traditional way to do this is to use the applicationDidEnterBackground method, which is called when your app is suspended. You can then save all the data you need in order to resume cleanly in case your app is later terminated.

However, if you're targeting iOS 6 and upwards you can take advantage of a new feature - State Presumption & Restoration (link to documentation). State restoration off-loads some (but not all) of the heavy lifting onto iOS, and it can automatically snapshot your UI and provides easier ways to preserve and restore data.

Answer 2

in your AppDelegate.m

- (void)applicationDidEnterBackground:(UIApplication *)application
{
    // Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later. 
    // If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
    // Save your data
}