Change app language in iOS without restarting the app

Question

I have seems some apps can change the language internally within the app without the need of restarting the app, I am wondering how they are implemented.

For example

Answer 1

I'm always using this way, it works perfectly, it might help you as well.

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you should set all the texts with NSLocalizableString(...) for the UI for the current language in the -viewWillAppear: method of your every UIViewController.

using this way you (I mean, the users) don't need to restart the application after changing the language of iOS in the Settings.

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of course, I'm using the Apple's standard localisation architecture.

UPDATE on (24 Oct 2013)

I've experienced the –viewWillAppear: method won't be performed for the actual view when the application enters to foreground; to solve that issue I also commit the procedure (see above) when I receive UIApplicationWillEnterForegroundNotification notification in the view.