How to change the text color of settings fragment in Android?

Question

I want to make a dark mode for my app, my only problem is that i cant change the text color in a fragment, the user is able to turn on/off the dark mode. That's why I can't change the theme in the manifest any solution for this problem?

if(!DarkTheme()) {
            setTheme(R.style.AppTheme);
        } else {
            setTheme(R.style.DarkAppTheme);
            getSupportActionBar().setBackgroundDrawable(new ColorDrawable(getResources().getColor(R.color.blacklight, null)));
            View fragment = (View) findViewById(R.id.settings_fragment);
            fragment.setBackgroundColor(getResources().getColor(R.color.Dark, null));
        }

That is to detect if dark mode is switched on, the background color changes and all, but I don't know how to change the text color in the fragment.

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools">

    <PreferenceCategory
        app:iconSpaceReserved="false"
        android:key="PREFS"
        android:title="Main settings (BETA)">

        <SwitchPreference
            android:key="darktheme"
            android:id="@+id/DarkTheme"
            app:iconSpaceReserved="false"
            android:title="Dark Theme"
            android:summary="Enable dark theme (BETA)"
            android:defaultValue="false" />

    </PreferenceCategory>

    <PreferenceCategory
        app:iconSpaceReserved="false"
        android:key="DOWN"
        android:title="Download settings">

        <CheckBoxPreference
            android:id="@+id/MobileData"
            android:key="mobiledata"
            android:title="Mobiele data"
            android:icon="@drawable/ic_network_cell_blue_24dp"
            android:summary="Download de voicemails op mobiele data"
            android:defaultValue="true"/>

    </PreferenceCategory>

    <PreferenceCategory
        app:iconSpaceReserved="false"
        android:key="Other"
        android:title="Other">

        <Preference android:title="Boodschap opnemen"
            android:id="@+id/Boodschap"
            android:key="@string/setVoicemail"
            android:summary="Spreek je eigen voicemail boodschap in">

            <intent
                android:action="android.intent.action.MAIN"
                android:targetPackage="com.tismi.voozzle_main"
                android:targetClass="com.tismi.voozzle_main.Popup" />

        </Preference>

        <Preference android:title="App uitleg"
            android:id="@+id/AppUitleg"
            android:key="AppUitleg"
            android:summary="Loop de uitleg van de app nog een keer door">

            <intent
                android:action="android.intent.action.MAIN"
                android:targetPackage="com.tismi.voozzle_main"
                android:targetClass="com.tismi.voozzle_main.Reopen_Expanation" />

        </Preference>

        <Preference android:title="Voozzle uitschakelen"
            android:key="voozzle_off"
            android:id="@+id/VoozzleOff"
            android:summary="Door op deze knop te klikken schakel je voozzle uit">

            <intent
                android:action="android.intent.action.MAIN"
                android:targetPackage="com.tismi.voozzle_main"
                android:targetClass="com.tismi.voozzle_main.tasks.TurnoffTask" />

        </Preference>

    </PreferenceCategory>

</PreferenceScreen>

This is my setting page (the fragment), I want to change the color of the titles and the summaries.

<style name="AppTheme" parent="Base.Theme.AppCompat.Light.DarkActionBar">
        <item name="colorPrimary">@color/colorPrimaryLight</item>
        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
        <item name="colorAccent">@color/colorAccent</item>
        <item name="android:windowBackground">@color/white</item>
        <item name="panelBackground">@color/white</item>
    </style>

    <style name="DarkAppTheme" parent="Base.Theme.AppCompat.Light.DarkActionBar">
        <item name="colorPrimary">@color/Dark</item>
        <item name="colorPrimaryDark">@color/Dark</item>
        <item name="colorAccent">@color/white</item>
        <item name="android:windowBackground">@color/Dark</item>
        <item name="panelBackground">@color/Dark</item>
        <item name="android:textColor">@color/white</item>
        <item name="android:textColorPrimary">@color/white</item>
        <item name="android:textColorSecondary">@color/white</item>
        <item name="android:textColorTertiary">@color/white</item>
    </style>

Answer 1

Try to use ContextThemeWrapper to set the theme.

final Context contextThemeWrapper = new ContextThemeWrapper(getActivity(), R.style.PreferenceScreen);
LayoutInflater localInflater = inflater.cloneInContext(contextThemeWrapper);

Within styles.xml define your theme.

<style name="PreferenceScreen" parent="YourApplicationThemeOrNone">
    <item name="android:textColor">@color/white</item>
</style>

Answer 2

Okay i figured it out and it's very simple

getContext().getTheme().applyStyle(R.style.PreferenceScreen, true);

This just apply's the style to the activity, thanks for the help!