Multiple Screen in AndroidX Preferences issue

Question

My goal is to build a multiple preference screen consisting of main preferences root.xml and subpreferences adv_preferences.xml using AndroidX Preferences. So far the application only consists of a MainActivity and some fragments such as a home screen fragment, MyRootFragment and AdvPreferencesFragment.

MainActivity does not contain any preferences related code.

MySettingsFragment.kt:

class MyRootFragment : PreferenceFragmentCompat() { // basic preferences
    override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
        setPreferencesFromResource(R.xml.root, rootKey)
    }
}
class AdvPreferencesFragment : PreferenceFragmentCompat() { // advanced preferences
    override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
        setPreferencesFromResource(R.xml.adv_preferences, rootKey)
    }
}

root.xml (basic preferences):

<androidx.preference.PreferenceScreen
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/settings">
    <CheckBoxPreference
        android:defaultValue="true"
        android:key="display_text"
        android:summaryOff="Invisible"
        android:summaryOn="Visible"
        android:title="blabla"/>
    <Preference
        app:title="Advanced Settings"
        app:summary="Test for using multiple screens"
        app:fragment="com.example.app.ui.settings.AdvPreferencesFragment"/>
</androidx.preference.PreferenceScreen>

adv_preferences.xml (advanced preferences):

<androidx.preference.PreferenceScreen
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">
    <Preference
        android:key="preference_key"
        android:title="placeholder"
        android:summary="placeholder" />
</androidx.preference.PreferenceScreen>

mobile_navigation.xml:

<fragment
    android:id="@+id/nav_root_preferences"
    android:name="com.example.app.ui.settings.MyRootFragment"
    android:label="@string/menu_preferences"
    tools:layout="@xml/root" />
<fragment
    android:id="@+id/nav_adv_preferences"
    android:name="com.example.app.ui.settings.AdvPreferencesFragment"
    android:label="@string/menu_preferences"
    tools:layout="@xml/adv_preferences" />

Everytime I tap Advanced Settings the app would crash with the following logcat message:

java.lang.IllegalStateException: Fragment AdvPreferencesFragment{...} declared target fragment MySettingsFragment{...} that does not belong to this FragmentManager!

How can I fix this? Everything seems to be hooked up correctly in both fragments, xml files and navigation graph.

I already tried to add the following

supportFragmentManager
    .beginTransaction()
    .replace(R.id.settings, MyRootFragment())
    .commit()

to the onCreate() method in MainActivity (as in the Android Jetpack Preference Guide) but this lead to the following crash and message (the app wouldn't even launch anymore):

java.lang.IllegalArgumentException: No view found for id … (com.example.app:id/settings) for fragment MySettingsFragment{...}

Checkout this answer https://stackoverflow.com/q/63305040/3894179 — Andra, Jun 29 '21 at 16:36

score -1 · Answer 1 · answered May 22 '20 at 07:03

try use <preference> replace <fragment> in mobile_navigation.xml

like this:

<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">
    <Preference
        app:fragment="com.xxx.mypreference.AdvPreferencesFragment"
        app:key="notification_category"
        app:title="Adv"
        app:summary="Adv">
    </Preference>
</PreferenceScreen>

Multiple Screen in AndroidX Preferences issue

1 Answers1