Develop Reference

How does one deep link into the preferences UI

I have an Android app that has used Preferences UI. I want to be able to deep link into the specific preference option. I can't figure out how to do that.
I have set up the preferences using the tutorial as follows
https://developer.android.com/guide/topics/ui/settings
https://medium.com/#JakobUlbrich/building-a-settings-screen-for-android-part-1-5959aa49337c (Part 1)
https://medium.com/#JakobUlbrich/building-a-settings-screen-for-android-part-2-2ba63e2d7d1d
https://medium.com/#JakobUlbrich/building-a-settings-screen-for-android-part-3-ae9793fd31ec
I have set up deep linking activity using this tutorial
https://developer.android.com/training/app-links/deep-linking
I want to be able to deep link directly into the one of the preferences.
public class SettingsActivity extends AppCompatActivity
implements PreferenceFragmentCompat.OnPreferenceStartFragmentCallback
{
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_settings);
FragmentFactory fragmentFactory = new AppFragmentFactory();
final FragmentManager fragmentManager = getSupportFragmentManager();
if (fragmentManager != null)
{
if (fragmentManager.findFragmentByTag(ROOT_FRAGMENT_TAG) == null)
{
final int containerId = R.id.detail_container;
final Fragment fragment = fragmentFactory.create(RootPreferencesFragment.class);
fragment.setArguments(savedInstanceState);
fragmentManager.beginTransaction()
.add(containerId, fragment, ROOT_FRAGMENT_TAG)
.commit();
}
}
}
}
#Override
public boolean onPreferenceStartFragment(PreferenceFragmentCompat callingFragment, Preference preference)
{
final Bundle arguments = preference.getExtras();
final Fragment fragment = fragmentFactory.create(getClassLoader(), preference.getFragment());
fragment.setArguments(arguments);
fragment.setTargetFragment(callingFragment, 0);
getSupportFragmentManager().beginTransaction()
.replace(R.id.detail_container, fragment)
.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN)
.setBreadCrumbTitle(preference.getTitle())
.addToBackStack(preference.getKey())
.commit();
return true;
}
RootPreferencesFragment
public class RootPreferencesFragment extends PreferenceFragmentCompat implements DialogFragmentCallback
{
#Override
public void onCreatePreferences(Bundle savedInstanceState, String rootKey)
{
final FragmentActivity activity = Objects.requireNonNull(getActivity());
// Notifications
final Preference notificationsPreference = preferencesFactory.create(
accountCategory,
Preference.class,
RootViewModel.ACCOUNT_NOTIFICATIONS_PREFERENCE_KEY,
R.string.PushNotifications,
RootViewModel.ACCOUNT_CATEGORY_KEY);
notificationsPreference.setFragment(NotificationPreferencesFragment.class.getName());
// General Category
final PreferenceCategory generalCategory = preferencesFactory.create(
preferenceScreen,
PreferenceCategory.class,
RootViewModel.GENERAL_CATEGORY_KEY,
R.string.preferences_general_group);
// About category
final PreferenceCategory aboutCategory = preferencesFactory.create(
preferenceScreen,
PreferenceCategory.class,
RootViewModel.ABOUT_CATEGORY_KEY,
R.string.preferences_about_group);
// About
final Preference aboutPreference = preferencesFactory.create(
aboutCategory,
Preference.class,
RootViewModel.ABOUT_PREFERENCE_KEY,
R.string.preferences_about);
aboutPreference.setSummary(aboutViewModel.getAppVersion());
aboutPreference.setFragment(AboutPreferencesFragment.class.getName());
}
}
I don't know how to trigger deep link into a specific NotificationsPreference. There is only one activity, but there are three preferences.

How to move back from Preferences subscreen to main screen in PreferenceFragmentCompat?

I am trying to implement a Settings screen using PreferenceFragmentCompat. My preference xml has a preference subscreen like this:
preferences.xml
<CheckBoxPreference
android:defaultValue="false"
android:key="#string/pref_sound_key"
android:summary="#string/pref_sound_summary"
android:title="#string/pref_sound_title" />
<PreferenceScreen android:title="Inner Screen">
<CheckBoxPreference
android:defaultValue="true"
android:key="#string/key_1"
android:title="#string/title_1" />
<CheckBoxPreference
android:defaultValue="true"
android:key="#string/key_1"
android:title="#string/title_1" />
<CheckBoxPreference
android:defaultValue="true"
android:key="#string/key_2"
android:title="#string/title_2" />
<CheckBoxPreference
android:defaultValue="true"
android:key="#string/key_3"
android:title="#string/title_3" />
</PreferenceScreen>
</PreferenceScreen>
Preference Main Screen
Now, in the app, the subscreen does not open until I implement PreferenceFragmentCompat.OnPreferenceStartScreenCallback interface in parent activity, as specified in PreferenceFragmentCompat doc.
MainActivity.java
public boolean onPreferenceStartScreen(PreferenceFragmentCompat preferenceFragmentCompat,
PreferenceScreen preferenceScreen) {
preferenceFragmentCompat.setPreferenceScreen(preferenceScreen);
return true;
}
Here's where the problem arises. On implementing the interface, the subscreen opens, but then there is no way I can find to move back to first screen.
Preference Subscreen
Pressing back key closes the app.
Is there any way I can put a back arrow on app bar so that pressing it will bring the main screen back?

By using setPreferenceScreen you are setting the root preference screen to the sub preference screen which is preventing you from having a hierarchy of preference screens to navigate back through.
I suggest that you treat each PreferenceScreen as a Fragment and add a new Fragment when you navigate into a sub screen.
#Override
public boolean onPreferenceStartScreen(PreferenceFragmentCompat preferenceFragmentCompat,
PreferenceScreen preferenceScreen) {
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
MyPreferenceFragment fragment = new MyPreferenceFragment();
Bundle args = new Bundle();
args.putString(PreferenceFragmentCompat.ARG_PREFERENCE_ROOT, preferenceScreen.getKey());
fragment.setArguments(args);
ft.add(R.id.fragment_container, fragment, preferenceScreen.getKey());
ft.addToBackStack(preferenceScreen.getKey());
ft.commit();
return true;
}
MyPreferenceFragment
public class MyPreferenceFragment extends AppPreferenceFragment {
public static final String FRAGMENT_TAG = "my_preference_fragment";
public MyPreferenceFragment() {
}
#Override
public void onCreatePreferences(Bundle bundle, String rootKey) {
setPreferencesFromResource(R.xml.preferences, rootKey);
}
}
AppPreferenceFragment
public abstract class AppPreferenceFragment extends PreferenceFragmentCompat {
#Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
// Set the default white background in the view so as to avoid transparency
view.setBackgroundColor(
ContextCompat.getColor(getContext(), R.color.background_material_light));
}
}
That way when you press the back button each Fragment will be popped from the stack.
For more information see this GitHub project

I have added a complete working example with screenshots and code snippets here in this post, I hope this will be helpful to someone.
It covers following scenarios:-- 1) A main setting screen with two checkboxes and a subscreen title. 2) On click of subscreen title, the new preference subscreen opens. 3) On back pressed, the control goes to main Settings screen. So the back press is handled properly.
The MainActivity looks like this(overridden onPreferenceStartScreen method handles the opening of new subscreen in a new window):--
public class MainActivity extends AppCompatActivity implements PreferenceFragmentCompat.OnPreferenceStartScreenCallback {
private static final String TAG = MainActivity.class.getName();
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
FragmentManager fragmentManager = getSupportFragmentManager();
Fragment fragment = null;
if (savedInstanceState == null) {
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragment = new AdvancedSettingsFragment().newInstance("Advanced Setting");
fragmentTransaction.add(R.id.fragment_container, fragment);
fragmentTransaction.commit();
}
}
#Override
public boolean onPreferenceStartScreen(PreferenceFragmentCompat preferenceFragmentCompat,
PreferenceScreen preferenceScreen) {
Log.d(TAG, "callback called to attach the preference sub screen");
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
AdvancedSettingsSubScreenFragment fragment = AdvancedSettingsSubScreenFragment.newInstance("Advanced Settings Subscreen");
Bundle args = new Bundle();
//Defining the sub screen as new root for the subscreen
args.putString(PreferenceFragmentCompat.ARG_PREFERENCE_ROOT, preferenceScreen.getKey());
fragment.setArguments(args);
ft.replace(R.id.fragment_container, fragment, preferenceScreen.getKey());
ft.addToBackStack(null);
ft.commit();
return true;
}
and finally the in subscreen fragment setPreferencesFromResource(R.xml.preferences, rootKey); handles the attachment of subscreen to the rootkey.
public class AdvancedSettingsSubScreenFragment extends PreferenceFragmentCompat {
private static final String TAG = AdvancedSettingsSubScreenFragment.class.getName();
public static final String PAGE_ID = "page_id";
public static AdvancedSettingsSubScreenFragment newInstance(String pageId) {
AdvancedSettingsSubScreenFragment f = new AdvancedSettingsSubScreenFragment();
Bundle args = new Bundle();
args.putString(PAGE_ID, pageId);
f.setArguments(args);
return (f);
}
#Override
public void onCreatePreferences(Bundle savedInstanceState, String rootKey) {
// rootKey is the name of preference sub screen key name , here--customPrefKey
setPreferencesFromResource(R.xml.preferences, rootKey);
Log.d(TAG, "onCreatePreferences of the sub screen " + rootKey);
}
}

Inner PreferenceScreen does not open with PreferenceFragmentCompat

My inner PreferenceScreen of PreferenceFragmentCompat is not showing, or seems to ignore tapping events.
I created MyPreferenceFragment that extends PreferenceFragmentCompat
public class MyPreferenceFragment extends PreferenceFragmentCompat {
#Override
public void onCreatePreferences(Bundle savedInstanceState, String rootKey) {
addPreferencesFromResource(R.xml.preferences);
}
}
then I changed my theme at styles.xml like
<style name="AppTheme" parent="#style/Theme.AppCompat.Light">
<item name="preferenceTheme">#style/PreferenceThemeOverlay</item>
</style>
And finally create my preferences.xml file like
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
<CheckBoxPreference android:title="Check Me"/>
<PreferenceScreen android:title="My Screen"> <!-- This is not opening -->
<EditTextPreference android:title="Edit text" />
</PreferenceScreen>
</PreferenceScreen>
At the build.gradle I have added both:
compile 'com.android.support:appcompat-v7:23.0.1'
compile 'com.android.support:preference-v7:23.0.1'
code of the Activity
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
}
activity_main.xml
<fragment xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/fragment"
android:name="com.mando.preferenceapp.MyPreferenceFragment"
android:layout_width="match_parent"
android:layout_height="match_parent" />
Testing the above code I cannot open / get into the preference screen. Am I missing something? Why this isn't working?

After spending many many hours with tries, searching and thankfully with some assistance from the creators of the support library. I've managed to make it work.
Step 1. Activity
public class MyActivity extends AppCompatActivity implements
PreferenceFragmentCompat.OnPreferenceStartScreenCallback {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (savedInstanceState == null) {
// Create the fragment only when the activity is created for the first time.
// ie. not after orientation changes
Fragment fragment = getSupportFragmentManager().findFragmentByTag(MyPreferenceFragment.FRAGMENT_TAG);
if (fragment == null) {
fragment = new MyPreferenceFragment();
}
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
ft.replace(R.id.fragment_container, fragment, MyPreferenceFragment.FRAGMENT_TAG);
ft.commit();
}
}
#Override
public boolean onPreferenceStartScreen(PreferenceFragmentCompat preferenceFragmentCompat,
PreferenceScreen preferenceScreen) {
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
MyPreferenceFragment fragment = new MyPreferenceFragment();
Bundle args = new Bundle();
args.putString(PreferenceFragmentCompat.ARG_PREFERENCE_ROOT, preferenceScreen.getKey());
fragment.setArguments(args);
ft.replace(R.id.fragment_container, fragment, preferenceScreen.getKey());
ft.addToBackStack(preferenceScreen.getKey());
ft.commit();
return true;
}
}
Tips.
Do not add the fragment by xml you will have crashes on orientation changes.
Handle the recreations of activity / fragment add in onCreate so as to avoid losing your fragment when inside a preference screen.
The host activity of the fragment should implement the PreferenceFragmentCompat.OnPreferenceStartScreenCallback and recreate fragments of the same instance.
Step 2. PreferenceFragment
public class MyPreferenceFragment extends PreferenceFragmentCompat {
public static final String FRAGMENT_TAG = "my_preference_fragment";
public MyPreferenceFragment() {
}
#Override
public void onCreatePreferences(Bundle bundle, String rootKey) {
setPreferencesFromResource(R.xml.preferences, rootKey);
}
}
Tips.
Use the method setPreferencesFromResource and take advantage of the rootKey of each screen. This way your code will be reused properly.
Keep in mind that if you have code like findPreference in your fragment it should have null checks as when you were in inner screens this will give you nothing.
The thing that is missing now is the implementation of the back arrow in the actionbar (home action) but this never works by itself ;-)
I' also created a demo app wrapping all this code you can find it on github.

Solution is to start another fragment of the same class but with different root key. No Activity actions involved.
#Override
public void onCreatePreferences(Bundle savedInstanceState, String rootKey){
if(getArguments() != null){
String key = getArguments().getString("rootKey");
setPreferencesFromResource(R.xml.preferences, key);
}else{
setPreferencesFromResource(R.xml.preferences, rootKey);
}
}
#Override
public void onNavigateToScreen(PreferenceScreen preferenceScreen){
ApplicationPreferencesFragment applicationPreferencesFragment = new ApplicationPreferencesFragment();
Bundle args = new Bundle();
args.putString("rootKey", preferenceScreen.getKey());
applicationPreferencesFragment.setArguments(args);
getFragmentManager()
.beginTransaction()
.replace(getId(), applicationPreferencesFragment)
.addToBackStack(null)
.commit();
}

I did it slightly differently, I'm launching a new activity for each screen. This seems to require less hacks: no need to mess with swapping fragments and background colors. You also get activity change animation as a bonus!
public class PreferencesActivity extends AppCompatActivity implements PreferenceFragmentCompat.OnPreferenceStartScreenCallback {
final static private String KEY = "key";
#Override protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.preferences);
setSupportActionBar((Toolbar) findViewById(R.id.toolbar));
ActionBar actionBar = getSupportActionBar();
if (actionBar != null) actionBar.setDisplayHomeAsUpEnabled(true);
if (savedInstanceState != null)
return;
Fragment p = new PreferencesFragment();
String key = getIntent().getStringExtra(KEY);
if (key != null) {
Bundle args = new Bundle();
args.putString(PreferenceFragmentCompat.ARG_PREFERENCE_ROOT, key);
p.setArguments(args);
}
getSupportFragmentManager().beginTransaction()
.add(R.id.preferences, p, null)
.commit();
}
#Override public boolean onPreferenceStartScreen(PreferenceFragmentCompat preferenceFragmentCompat, PreferenceScreen preferenceScreen) {
Intent intent = new Intent(PreferencesActivity.this, PreferencesActivity.class);
intent.putExtra(KEY, preferenceScreen.getKey());
startActivity(intent);
return true;
}
#Override public boolean onOptionsItemSelected(MenuItem item) {
if (item.getItemId() == android.R.id.home) {
onBackPressed();
return true;
}
return super.onOptionsItemSelected(item);
}
public static class PreferencesFragment extends PreferenceFragmentCompat implements ... {
private static final String FRAGMENT_DIALOG_TAG = "android.support.v7.preference.PreferenceFragment.DIALOG";
private String key;
#Override public void onCreatePreferences(Bundle bundle, String key) {
setPreferencesFromResource(R.xml.preferences, this.key = key);
}
// this only sets the title of the action bar
#Override public void onActivityCreated(Bundle savedInstanceState) {
ActionBar actionBar = ((AppCompatActivity) getActivity()).getSupportActionBar();
if (actionBar != null) actionBar.setTitle((key == null) ? "Settings" : findPreference(key).getTitle());
super.onActivityCreated(savedInstanceState);
}
}
}
xml:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_margin="0dp"
android:orientation="vertical"
android:padding="0dp"
android:id="#+id/preferences">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary" />
<!-- preference fragment will be inserted here programmatically -->
</LinearLayout>

Another solution is to track the preference screens yourself and use the PreferenceFragmentCompat api
Here's the basic solution. (It doesn't cover all the edge cases, see advanced solution below)
Ensure you have configChanges="orientation" to prevent create/destroy
<activity
android:name=".MyPreferencesActivity"
android:configChanges="orientation" />
In the Activity you want to keep a Stack of PreferenceScreens and push/pop as needed
/* track the screens as a Stack */
private Stack<PreferenceScreen> preferenceScreens = new Stack<>();
// ensure your Activity implements PreferenceFragmentCompat.OnPreferenceStartScreenCallback
#Override
public boolean onPreferenceStartScreen(PreferenceFragmentCompat preferenceFragmentCompat, PreferenceScreen preferenceScreen) {
preferenceScreens.push(preferenceFragmentCompat.getPreferenceScreen());
preferenceFragmentCompat.setPreferenceScreen(preferenceScreen);
return true;
}
#Override
public void onBackPressed() {
if (preferenceScreens.empty()) {
super.onBackPressed();
} else {
prefsFragment.setPreferenceScreen(preferenceScreens.pop());
}
}
Optional: In your Fragment that extends PreferenceFragmentCompat, add setRetainInstance(true). (Note that without
this it will likely work also, but it 'could' break occasionally. If you set 'Don't keep Activities' to true, and
you'll see that it will get collected)
#Override
public void onCreatePreferences(Bundle savedInstanceState, String rootKey) {
setRetainInstance(true);
// Load the preferences from an XML resource
setPreferencesFromResource(R.xml.preferences, rootKey);
...
That's it! Except that if you want to cover edge cases...
Advanced Solution (If you set 'Don't Keep Activities to True, you'll need to ensure you can rebuild everything from savedInstanceState)
Note that the accepted answer doesn't actually preserve state.
set 'Don't Keep Activities' to True
navigate to a nested PreferenceScreen
Press home and then navigate back to the app
It 'should' still be on the Nested PreferenceScreen, but it's actually on the root one
Full Advanced Solution using PreferenceFragmentCompat api and preserving the PreferenceScreen stack
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.preference.PreferenceFragmentCompat;
import android.support.v7.preference.PreferenceScreen;
import java.util.ArrayList;
import java.util.Objects;
import java.util.Stack;
/**
* Class to Show the preference screen with Activity keeping state
* #author Aaron Vargas
*/
public class MyPreferencesActivityStateful extends AppCompatActivity implements PreferenceFragmentCompat.OnPreferenceStartScreenCallback {
private static final String PREFERENCE_SCREENS = "PREFERENCE_SCREENS";
private PrefsFragment prefsFragment;
private Stack<PreferenceScreen> preferenceScreens = new Stack<>();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Display the fragment as the main content. Re-Use if possible
String tag = PrefsFragment.class.getName();
prefsFragment = (PrefsFragment) getSupportFragmentManager().findFragmentByTag(tag);
if (prefsFragment == null) prefsFragment = new PrefsFragment();
getSupportFragmentManager().beginTransaction().replace(android.R.id.content,
prefsFragment, tag).commit();
}
#Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
super.onRestoreInstanceState(savedInstanceState);
// rebuild preferenceScreen stack
for (String screenKey : Objects.requireNonNull(savedInstanceState.getStringArrayList(PREFERENCE_SCREENS))) {
preferenceScreens.push((PreferenceScreen) prefsFragment.findPreference(screenKey));
}
PreferenceScreen preferenceScreen = preferenceScreens.pop();
if (preferenceScreen != prefsFragment.getPreferenceScreen()) { // optimize if same
prefsFragment.setPreferenceScreen(preferenceScreen);
}
}
#Override
public boolean onPreferenceStartScreen(PreferenceFragmentCompat preferenceFragmentCompat, PreferenceScreen preferenceScreen) {
preferenceScreens.push(preferenceFragmentCompat.getPreferenceScreen());
preferenceFragmentCompat.setPreferenceScreen(preferenceScreen);
return true;
}
#Override
public void onBackPressed() {
// account for onRestore not getting called equally to onSave
while (preferenceScreens.contains(prefsFragment.getPreferenceScreen())) {
preferenceScreens.remove(prefsFragment.getPreferenceScreen());
}
if (preferenceScreens.empty()) {
super.onBackPressed();
} else {
prefsFragment.setPreferenceScreen(preferenceScreens.pop());
}
}
#Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
preferenceScreens.push(prefsFragment.getPreferenceScreen());
ArrayList<String> keys = new ArrayList<>(preferenceScreens.size());
for (PreferenceScreen screen : preferenceScreens) {
keys.add(screen.getKey());
}
outState.putStringArrayList(PREFERENCE_SCREENS, keys);
}
public static class PrefsFragment extends PreferenceFragmentCompat {
#Override
public void onCreatePreferences(Bundle savedInstanceState, String rootKey) {
setRetainInstance(true); // ensure in manifest - android:configChanges="orientation"
// Load the preferences from an XML resource
setPreferencesFromResource(R.xml.preferences, rootKey);
}
}
}
You can also handle all this in your Fragment instead of the Activity. Here's a gist of that https://gist.github.com/aaronvargas/0f210ad8643b512efda4acfd524e1232

Using Navigation Component (Android Jetpack) and Kotlin it's very easy now:
class PrefsFragment : PreferenceFragmentCompat() {
private val args: PrefsFragmentArgs by navArgs()
override fun onCreatePreferences(state: Bundle?, rootKey: String?) {
setPreferencesFromResource(R.xml.prefs, args.rootKey)
}
override fun onNavigateToScreen(preferenceScreen: PreferenceScreen?) {
findNavController().navigate(
PrefsFragmentDirections.changeRoot(preferenceScreen!!.key)
)
}
}

Based on #squirrel Intent solution, I made it work this way. It requires even less hacking.
Activity:
import android.support.v7.app.AppCompatActivity;
public class SettingsActivity extends AppCompatActivity {
public static final String TARGET_SETTING_PAGE = "target";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
SettingsFragment settingsFragment = new SettingsFragment();
Intent intent = getIntent();
if (intent != null) {
String rootKey = intent.getStringExtra(TARGET_SETTING_PAGE);
if (rootKey != null) {
settingsFragment.setArguments(Bundler.single(TARGET_SETTING_PAGE, rootKey));
}
}
getFragmentManager().beginTransaction()
.replace(android.R.id.content, settingsFragment)
.commit();
}
}
Fragment:
import android.support.v14.preference.PreferenceFragment;
public class SettingsFragment extends PreferenceFragment {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Bundle arguments = getArguments();
if (arguments != null && arguments.getString(TARGET_SETTING_PAGE) != null) {
setPreferencesFromResource(R.xml.preferences, arguments.getString(TARGET_SETTING_PAGE));
} else {
addPreferencesFromResource(R.xml.preferences);
}
}
#Override
public void onNavigateToScreen(PreferenceScreen preferenceScreen) {
Intent intent = new Intent(getActivity(), SettingsActivity.class)
.putExtra(TARGET_SETTING_PAGE, preferenceScreen.getKey());
startActivity(intent);
super.onNavigateToScreen(preferenceScreen);
}
}
It is sad you need so much hacks in the support appcompat libraries for something that works flawlessly out-of-the-box in standard android.

Alternative using Navigation component + androidx.appcomat:
https://stackoverflow.com/a/59732509/5437789
With this, you wont loose the back stack and go back to main page settings when you press back button.

Here is a simple solution from android documentation. To implement inner preference screen navigation with PreferenceFragmentCompact all you have to do is add fragment attribute to the embedded preference screen giving the fragment full path to navigate to eg. com.example.FragmentName.
Sample code:
<PreferenceCategory app:title="#string/choose_theme"
android:icon="#drawable/ic_baseline_color_lens_24">
<SwitchPreference
android:title="#string/apply_night_mode"
android:key="#string/key_enable_night_mode"/>
<PreferenceScreen
android:fragment="com.example.simbokeyboard.BlankFragment"
android:title="Custom Theme"
android:summary="#string/theme_summary">
<Preference
android:key="#string/choose_theme"
android:title="#string/choose_theme"
android:layout="#layout/theme_chooser"/>
</PreferenceScreen>
</PreferenceCategory>

Reloading PreferenceFragment when new language selected in preferences

In my app's preferences I have an option to change app's language.
public class Fragment_Preferences extends PreferenceFragment {
private SharedPreferences.OnSharedPreferenceChangeListener prefListener;
SharedPreferences preferences;
#Override
public void onCreate(Bundle savedInstanceState) {
preferences = PreferenceManager.getDefaultSharedPreferences(getActivity());
super.onCreate(savedInstanceState);
addPreferencesFromResource(R.xml.preferences);
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(getActivity());
prefListener = new SharedPreferences.OnSharedPreferenceChangeListener() {
public void onSharedPreferenceChanged(SharedPreferences prefs, String key) {
if(key.equals("language_preference"))
{
// Set language change flag to true -
// the Main Fragment will be recreate when this fragment finishes and the main restarts
Common_Methods.set_locale_changed(true);
}
}
};
prefs.registerOnSharedPreferenceChangeListener(prefListener);
}
}
So when I change the language, the preference fragment doesn't change it's language immediately. I have to exit preferences, then in my Fragment or Activity (depends from where I called for Preference fragment) I have this code, which restarts the current fragment or activity with new language settings:
public void onConfigurationChanged(Configuration newConfig) {
Handler handler = new Handler();
handler.postDelayed(new Runnable()
{
#Override
public void run()
{
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.HONEYCOMB)
{
finish();
startActivity(getIntent());
} else {recreate();}
}
}, 1);
Common_Methods.set_locale_changed(false); // Reset the Language change flag to prevent repeating Fragment recreation.
super.onConfigurationChanged(newConfig);
}
If I reopen Preference fragment at that point - it will be in the new selected language.
I tried to copy the above method to my Preference_Fragment, but I'm getting errors. So the question is: how can I recreate/reload the Preference_Fragment with the new language immediately after it was selected, without having to exit the fragment first?

It is best if you let the activity know (through getActivity() and casting) that you want your fragment updated, and add logic to the activity to remove the fragment and add a new instance.
In your settings activity:
public void restartFragment() {
SettingsFragment fragment = new SettingsFragment();
getFragmentManager().beginTransaction().replace(android.R.id.content, fragment).commit();
}
And in your settings fragment:
((SettingsActivity) getActivity()).restartFragment();

Floren's answer didn't work for me (maybe due to using the Android Support Library), but it lead me to the following solution based on the same basic idea from Florens. The difference is removing and adding the fragment instead of replacing:
In your activity:
public void restartFragment() {
FragmentManager fm = getSupportFragmentManager();
if (fragment != null) {
FragmentTransaction ft = fm.beginTransaction();
ft.remove(fragment);
ft.commit();
}
fragment = <new instance>;
FragmentTransaction ft = fm.beginTransaction();
ft.add(R.id.fragmentActivity, main, "Main");
ft.commit();
}
In your fragment:
((<your activity>)getActivity()).restartFragment();

Is it possible to auto-scroll down a PreferenceFragment to a desired (settings) entry?

I'm using startActivity(new Intent(this, SettingsActivity.class)) from an Activity to call the PreferenceFragment of my app when a certain user interaction is required to be performed into the preferences.
I think would be good to scroll down to reach the involved preference.
I found solutions about how to scroll views into ScrollViews and ListViews, but nothing related to PreferenceFragments.
My preferences look like:
public class SettingsActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// ...
PreferenceManager.setDefaultValues(this, R.xml.settings, false);
getFragmentManager().beginTransaction()
.replace(android.R.id.content, new SettingsFragment())
.commit();
}
public static class SettingsFragment extends PreferenceFragment implements OnSharedPreferenceChangeListener {
//preferences:
private Preference p
// [...]
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
addPreferencesFromResource(R.xml.settings);
//preference click listeners...
p = (Preference) findPreference("PR_NAME");
p.setOnPreferenceClickListener(new OnPreferenceClickListener() {
public boolean onPreferenceClick(Preference preference) {
// ...
return true;
}
});
// [...]
}
}
}
Thanks for any suggestion

To scroll in PreferenceScreen (Setting/Preferences), Use this for Android API 24.1.+ or with androidX API
public void scrollToPreference (String key)

yes, it is possible but it is hacky so nor recommended. it assumes that Preferences are backed by a ListView with id == android.R.id.list, so when you have reference to that ListView you can call setSelection(position)