Identifying RTL language in Android

Question

Is there a way to identify RTL (right-to-left) language, apart from testing language code against all RTL languages?

Since API 17+ allows several resources for RTL a

Answer 1

@cyanide's answer has the right approach but a critical bug.

Character.getDirectionality returns the Bi-directional (bidi) character type. Left-to-right text is a predictable type L and right-to-left is also predictably type R. BUT, Arabic text returns another type, type AL.

I added a check for both type R and type AL and then manually tested every RTL language Android comes with: Hebrew (Israel), Arabic (Egypt), and Arabic (Israel).

As you can see, this leaves out other right-to-left languages, so I was concerned that as Android adds these languages, there might have a similar issue and one might not notice right away.

So I tested manually each RTL language.

• Arabic (العربية) = type AL
• Kurdish (کوردی) = type AL
• Farsi (فارسی) = type AL
• Urdu (اردو) = type AL
• Hebrew (עברית) = type R
• Yiddish (ייִדיש) = type R

So it looks like this should work great:

public static boolean isRTL() {
    return isRTL(Locale.getDefault());
}

public static boolean isRTL(Locale locale) {
    final int directionality = Character.getDirectionality(locale.getDisplayName().charAt(0));
    return directionality == Character.DIRECTIONALITY_RIGHT_TO_LEFT ||
           directionality == Character.DIRECTIONALITY_RIGHT_TO_LEFT_ARABIC;
}

Thanks @cyanide for sending me the right direction!