How to add locale(with country) to font resources (Support Library v26)?

Question

Google published the official font resources handling since support library v26 released: https://developer.android.com/guide/topics/ui/look-and-feel/fonts-in-xml.html

However, looks like I cannot add country qualifier for the font resources folder.

I have an app which has 3 languages: English, Traditional Chinese and Simplified Chinese.

And I tried to name my font folder under res this way:
font
font-zh
font-zh_CN
(I have also tried font-zh-CN)

(Note that zh is the language, while CN is the country. With some more context for your information - In China we all use "Chinese", but there are Simplified Chinese and Traditional Chinese; Moreover, Hong Kong and Taiwan both use Traditional Chinese but the way we use them are a bit different. Most importantly, typefaces have separate files for Traditional Chinese and Simplified Chinese, due to the fact that they are quite different in their shapes.)

But I cannot build the project. Android Studio keeps telling me that font-zh_CN (or font-zh-CN) is an invalid resource directory name.

This does not happen for my values-zh_CN folder (nor values-zh-CN).

Question:

How do you use different fonts for the same language but different country, using the new official method since API 26?

Answer 1

The pattern for resource folder names is defined in Table 2 here: https://developer.android.com/guide/topics/resources/providing-resources.html#Alternative%20Resources

Specifically, try:

font-zh-rCN