Res folders. Read file manually

Res folders. Read file manually

I have String.xml files organized by language inside my res folder like:
res/values
res/values-de
res/values-es
res/values-fr
res/values-ga
res/values-hi
res/values-it
...
By default the app make a choose according to device's language or by
finding Best Match. Now, I want to include a language selector to let the
user choose any of them. Is there a way to read those files without moving
them to assets folder or any other place? Is it something it can be done
once or should I do it by every activity?
I found some "solutions", but they are not permanent nor clean since they
need to be done on each activity.