Android EditTextPreference default value not shown

Question

I have a XML PreferenceScreen that holds an EditTextPreference like below

<EditTextPreference
            app:key="preference_key"
            app:title="test preference"
            app:useSimpleSummaryProvider="true"/>

If the user has not set anything "Not set" is shown as expected. However I want this to have a default value which is also shown, but the value is dynamic based on some other settings. I already have the code to get said setting, but I just don't know how to set it in the EditTextPrefrence (preference_key) programmatically?

If i try with Preference.setDefaultValue it still showns "Not set"