How to change iPhone app language during runtime?

Question

Is there a way to change the application language during runtime?

So, after the change NSLocalizedString immediately returns the string for the new language.

What I'm doing now is changing the language using the code below:

- (void)onChangeLanguage: (id)sender 
{
    NSArray *lang = [NSArray arrayWithObjects:((InfoWhatever *)sender).language, nil];
    [[NSUserDefaults standardUserDefaults] setObject:lang forKey:@"AppleLanguages"];
    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
    NSArray *languages = [defaults objectForKey:@"AppleLanguages"];
    NSString *currentLanguage = [languages objectAtIndex:0];

    NSLog(@"Current language: %@", currentLanguage);
}

The language will change but only after restarting the app.

Answer 1

NSUserDefaults* userDefaults = [NSUserDefaults standardUserDefaults];
NSMutableArray* languages = [userDefaults objectForKey:@"AppleLanguages"];
[languages insertObject:@"de" atIndex:0]; // ISO639-1
[[NSUserDefaults standardUserDefaults] synchronize];

Answer 2

The trick to use specific language by selecting it from the app is to force the NSLocalizedString to use specific bundle depending on the selected language ,

here is the post i have written for this http://learning-ios.blogspot.com/2011/04/advance-localization-in-ios-apps.html

and here is the code of one sample app https://github.com/object2dot0/Advance-Localization-in-ios-apps