Changing the device language when application is in background

I am running my iPod touch application and then go in background and change the device language from Settings application and try to bring that application on foreground. My application gets restarted and I do not land on the screen where I left the application when I went into the background.

Is this because a KILL 开发者_开发百科signal is sent by settings application when language was changed? Is it the desired behavior?

I wasn't aware the switching the language would cause apps to be terminated, but that's not shocking. It's a very straightforward way to get what the user wants. Your problem isn't the language change, though. The problem is that you're not responding correctly to a notification of termination. You can be terminated at any time when you're in the background, and it's your job to deal with it.

Your application delegate should implement applicationWillTerminate: (or you can observe UIApplicationWillTerminateNotification wherever it is convenient). When you receive this, you should save off sufficient information to get yourself back to where you were when you restart. As much as possible, you should make it look to the user that you did not terminate. The easiest place to save state is usually in NSUserDefaults, but you can use any mechanism you like.

Handling application restart is one of those things that separates excellent iOS applications from "good enough."