CHAPTER 21: Application Localization

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You should choose to localize only those resources that are affected by language or country. For example, if an image in your application has no words and its meaning is universal, there’s no need to localize that image.

Strings Files

What do you do about string literals and string constants in your source code? Consider this source code from the previous chapter:

UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Error accessing photo library"

message:@"Device does not support a photo library" delegate:nil

cancelButtonTitle:@"Drat!"

otherButtonTitles:nil]; [alert show];

If you’ve gone through the effort of localizing your application for a particular audience, you certainly don’t want to be presenting alerts written in the development base language. The answer is to store these strings in special text files called strings files.

What’s in a Strings File?

Strings files are nothing more than Unicode (UTF-16) text files that contain a list of string pairs, each identified by a comment. Here is an example of what a strings file might look like in your application:

/* Used to ask the user his/her first name */ "First Name" = "First Name";

/* Used to get the user's last name */ "Last Name" = "Last Name";

/* Used to ask the user's birth date */ "Birthday" = "Birthday";

The values between the /* and the */ characters are just comments for the translator. They are not used in the application, and you could skip adding them, though they’re a good idea. The comments give context, showing how a particular string is being used in the application.

You’ll notice that each line lists the same string twice. The string on the left side of the equal sign acts as a key, and it will always contain the same value, regardless of language. The value on the right side of the equal sign is the one that is translated to the local language. So, the preceding strings file, localized into French, might look like this:

/* Used to ask the user his/her first name */ "First Name " = "Prénom";

/* Used to get the user's last name */ "Last Name " = "Nom de famille";

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