You need to have different strings.xml to support different langauges.
http://developer.android.com/training/basics/supporting-devices/languages.html
What is the list of supported languages/locales on Android?.
I don't think there is support for persian language.
Example:
MyProject/
res/
values/
strings.xml
values-es/
strings.xml
values-fr/
strings.xml
values-ar/ // for arabic
strings.xml
For spanish
<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="title">Mi Aplicación</string>
<string name="hello_world">Hola Mundo!</string>
</resources>
At runtime, the Android system uses the appropriate set of string resources based on the locale currently set for the user's device.
http://developer.android.com/guide/topics/resources/localization.html
TextView textView = new TextView(this);
textView.setText(R.string.hello_world);
Check the doc for more info
http://developer.android.com/training/basics/supporting-devices/languages.html