LeanbackPreferenceFragmentCompat

public abstract class LeanbackPreferenceFragmentCompat
extends BaseLeanbackPreferenceFragmentCompat

java.lang.Object
   ↳ androidx.fragment.app.Fragment
     ↳ androidx.preference.PreferenceFragmentCompat
       ↳ androidx.leanback.preference.BaseLeanbackPreferenceFragmentCompat
         ↳ androidx.leanback.preference.LeanbackPreferenceFragmentCompat


This fragment provides a fully decorated leanback-style preference fragment, including a list background and header.

The following sample code shows a simple leanback preference fragment that is populated from a resource. The resource it loads is:

<PreferenceScreen
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto">

    <PreferenceCategory
            android:title="@string/basic_preferences">

        <Preference
                android:key="preference"
                android:title="@string/title_basic_preference"
                android:summary="@string/summary_basic_preference"/>

        <Preference
                android:key="stylized"
                android:title="@string/title_stylish_preference"
                android:summary="@string/summary_stylish_preference"/>

        <Preference
                android:key="icon"
                android:title="@string/title_icon_preference"
                android:summary="@string/summary_icon_preference"
                android:icon="@android:drawable/ic_menu_camera"/>

        <Preference
                android:key="single_line_title"
                android:title="@string/title_single_line_title_preference"
                android:summary="@string/summary_single_line_title_preference"
                app:singleLineTitle="true"/>
    </PreferenceCategory>

    <PreferenceCategory
            android:title="@string/widgets">

        <CheckBoxPreference
                android:key="checkbox"
                android:title="@string/title_checkbox_preference"
                android:summary="@string/summary_checkbox_preference"/>

        <SwitchPreferenceCompat
                android:key="switch"
                android:title="@string/title_switch_preference"
                android:summary="@string/summary_switch_preference"/>

        <DropDownPreference
                android:key="dropdown"
                android:title="@string/title_dropdown_preference"
                android:entries="@array/entries"
                app:useSimpleSummaryProvider="true"
                android:entryValues="@array/entry_values"/>

        <SeekBarPreference
                android:key="seekbar"
                android:title="@string/title_seekbar_preference"
                android:max="10"
                android:defaultValue="5"/>
    </PreferenceCategory>

    <PreferenceCategory
            android:title="@string/dialogs">

        <EditTextPreference
                android:key="edittext"
                android:title="@string/title_edittext_preference"
                app:useSimpleSummaryProvider="true"
                android:dialogTitle="@string/dialog_title_edittext_preference"/>

        <ListPreference
                android:key="list"
                android:title="@string/title_list_preference"
                app:useSimpleSummaryProvider="true"
                android:entries="@array/entries"
                android:entryValues="@array/entry_values"
                android:dialogTitle="@string/dialog_title_list_preference"/>

        <MultiSelectListPreference
                android:key="multi_select_list"
                android:title="@string/title_multi_list_preference"
                android:summary="@string/summary_multi_list_preference"
                android:entries="@array/entries"
                android:entryValues="@array/entry_values"
                android:dialogTitle="@string/dialog_title_multi_list_preference"/>
    </PreferenceCategory>

    <PreferenceCategory
            android:key="advanced"
            android:title="@string/advanced_attributes"
            app:initialExpandedChildrenCount="1">

        <Preference
                android:key="expandable"
                android:title="@string/title_expandable_preference"
                android:summary="@string/summary_expandable_preference"/>

        <Preference
                android:title="@string/title_intent_preference"
                android:summary="@string/summary_intent_preference">

            <intent android:action="android.intent.action.VIEW"
                    android:data="http://www.android.com"/>

        </Preference>

        <SwitchPreferenceCompat
                android:key="parent"
                android:title="@string/title_parent_preference"
                android:summary="@string/summary_parent_preference"/>

        <SwitchPreferenceCompat
                android:key="child"
                android:dependency="parent"
                android:title="@string/title_child_preference"
                android:summary="@string/summary_child_preference"/>

        <SwitchPreferenceCompat
                android:key="toggle_summary"
                android:title="@string/title_toggle_summary_preference"
                android:summaryOn="@string/summary_on_toggle_summary_preference"
                android:summaryOff="@string/summary_off_toggle_summary_preference"/>

        <Preference
                android:key="copyable"
                android:title="@string/title_copyable_preference"
                android:summary="@string/summary_copyable_preference"
                android:selectable="false"
                app:enableCopying="true"/>
    </PreferenceCategory>

</PreferenceScreen>

The fragment needs only to implement PreferenceFragmentCompat.onCreatePreferences(Bundle, String) to populate the list of preference objects:

public static class SettingsFragment extends LeanbackSettingsFragmentCompat {
    @Override
    public void onPreferenceStartInitialScreen() {
        startPreferenceFragment(new DemoFragment());
    }

    @Override
    public boolean onPreferenceStartFragment(PreferenceFragmentCompat caller, Preference pref) {
        final Bundle args = pref.getExtras();
        final Fragment f = getChildFragmentManager().getFragmentFactory().instantiate(
                requireActivity().getClassLoader(), pref.getFragment());
        f.setArguments(args);
        f.setTargetFragment(caller, 0);
        if (f instanceof PreferenceFragmentCompat
                || f instanceof PreferenceDialogFragmentCompat) {
            startPreferenceFragment(f);
        } else {
            startImmersiveFragment(f);
        }
        return true;
    }

    @Override
    public boolean onPreferenceStartScreen(PreferenceFragmentCompat caller,
            PreferenceScreen pref) {
        final Fragment fragment = new DemoFragment();
        final Bundle args = new Bundle(1);
        args.putString(PreferenceFragmentCompat.ARG_PREFERENCE_ROOT, pref.getKey());
        fragment.setArguments(args);
        startPreferenceFragment(fragment);
        return true;
    }
}

/**
 * The fragment that is embedded in SettingsFragment
 */
public static class DemoFragment extends LeanbackPreferenceFragmentCompat {

    @Override
    public void onCreatePreferences(Bundle savedInstanceState, String rootKey) {
        // Load the preferences from an XML resource
        setPreferencesFromResource(R.xml.preferences, rootKey);
    }
}

Summary

Inherited constants

Public constructors

LeanbackPreferenceFragmentCompat()

Public methods

View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)

Called to have the fragment instantiate its user interface view.

void onViewCreated(View view, Bundle savedInstanceState)

Called immediately after onCreateView(LayoutInflater, ViewGroup, Bundle) has returned, but before any saved state has been restored in to the view.

void setTitle(CharSequence title)

Set the title to be shown above the preference list

Inherited methods

Public constructors

LeanbackPreferenceFragmentCompat

public LeanbackPreferenceFragmentCompat ()

Public methods

onCreateView

public View onCreateView (LayoutInflater inflater, 
                ViewGroup container, 
                Bundle savedInstanceState)

Called to have the fragment instantiate its user interface view. This is optional, and non-graphical fragments can return null. This will be called between onCreate(Bundle) and onActivityCreated(Bundle).

A default View can be returned by calling Fragment(int) in your constructor. Otherwise, this method returns null.

It is recommended to only inflate the layout in this method and move logic that operates on the returned View to onViewCreated(View, Bundle).

If you return a View from here, you will later be called in onDestroyView() when the view is being released.

Parameters
inflater LayoutInflater: The LayoutInflater object that can be used to inflate any views in the fragment,

container ViewGroup: If non-null, this is the parent view that the fragment's UI should be attached to. The fragment should not add the view itself, but this can be used to generate the LayoutParams of the view.

savedInstanceState Bundle: If non-null, this fragment is being re-constructed from a previous saved state as given here.

Returns
View Return the View for the fragment's UI, or null.

onViewCreated

public void onViewCreated (View view, 
                Bundle savedInstanceState)

Called immediately after onCreateView(LayoutInflater, ViewGroup, Bundle) has returned, but before any saved state has been restored in to the view. This gives subclasses a chance to initialize themselves once they know their view hierarchy has been completely created. The fragment's view hierarchy is not however attached to its parent at this point.

Parameters
view View: The View returned by onCreateView(LayoutInflater, ViewGroup, Bundle).

savedInstanceState Bundle: If non-null, this fragment is being re-constructed from a previous saved state as given here.

setTitle

public void setTitle (CharSequence title)

Set the title to be shown above the preference list

Parameters
title CharSequence: Title text to be shown