Settings: language chooser is now available for all Android versions.

Part of #1974

src/main/AndroidManifest.xml

@@ -401,6 +401,16 @@ limitations under the License.
             android:name=".services.TrackDeleteService"
             android:exported="false"
             android:permission="android.permission.BIND_JOB_SERVICE"/>
+
+        <!--Necessary for SDK < 33 to (re-)store per app locale information-->
+        <service
+            android:name="androidx.appcompat.app.AppLocalesMetadataHolderService"
+            android:enabled="false"
+            android:exported="false">
+            <meta-data
+                android:name="autoStoreLocales"
+                android:value="true" />
+        </service>
     </application>
 
     <queries>

src/main/java/de/dennisguse/opentracks/settings/LocalePreference.java

@@ -1,25 +1,36 @@
 package de.dennisguse.opentracks.settings;
 
+import android.annotation.SuppressLint;
 import android.app.LocaleConfig;
 import android.content.Context;
 import android.os.Build;
 import android.os.LocaleList;
 import android.util.AttributeSet;
+import android.util.Log;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.appcompat.app.AppCompatDelegate;
+import androidx.core.app.LocaleManagerCompat;
 import androidx.core.os.LocaleListCompat;
 import androidx.preference.ListPreference;
 
+import org.xmlpull.v1.XmlPullParser;
+import org.xmlpull.v1.XmlPullParserException;
+
+import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Comparator;
+import java.util.List;
 import java.util.Locale;
+import java.util.Optional;
 
 import de.dennisguse.opentracks.R;
 
 public class LocalePreference extends ListPreference {
 
+    private String TAG = LocalePreference.class.getSimpleName();
+
     public LocalePreference(@NonNull Context context, @Nullable AttributeSet attrs, int defStyleAttr, int defStyleRes) {
         super(context, attrs, defStyleAttr, defStyleRes);
         init(context);
@@ -40,18 +51,17 @@ public class LocalePreference extends ListPreference {
         init(context);
     }
 
+    // /data/user/0/de.dennisguse.opentracks.debug/files/androidx.appcompat.app.AppCompatDelegate.application_locales_record_file: open failed: ENOENT (No such file or directory)
     private void init(Context context) {
         setPersistent(false);
-        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.UPSIDE_DOWN_CAKE) {
-            setEnabled(false);
-            return;
-        }
+
         LocaleItem systemDefaultLocale = new LocaleItem("", context.getString(R.string.settings_locale_system_default));
 
         LocaleItem currentLocale = new LocaleItem(Locale.getDefault().toLanguageTag(), Locale.getDefault().getDisplayName());
 
         // All available options
-        LocaleList supportedLocales = LocaleConfig.fromContextIgnoringOverride(context).getSupportedLocales();
+        LocaleList supportedLocales = getLocaleListCompat();
+
         ArrayList<LocaleItem> localeItemsSorting = new ArrayList<>();
         for (int i = 0; i < supportedLocales.size(); i++) {
             Locale current = supportedLocales.get(i);
@@ -104,4 +114,36 @@ public class LocalePreference extends ListPreference {
             String displayName
     ) {
     }
+
+    // TODO Get this functionality from any Androidx compat library: should be in LocaleListCompat or LocaleManagerCompat
+    // 2024-12-12: on Android 14-: LocaleManagerCompat.getApplicationLocales(getContext()) returned "[]"
+    // See: https://stackoverflow.com/questions/78116375/per-app-language-preferences-get-list-of-apps-available-language-programmatic
+    @Deprecated
+    private LocaleList getLocaleListCompat() {
+        var a = LocaleManagerCompat.getApplicationLocales(getContext());
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.UPSIDE_DOWN_CAKE) {
+            return LocaleConfig.fromContextIgnoringOverride(getContext()).getSupportedLocales();
+        }
+
+        @SuppressLint("DiscouragedApi") int localesConfigId = getContext().getResources().getIdentifier("_generated_res_locale_config", "xml", getContext().getPackageName());
+
+        List<String> localeList = new ArrayList<>();
+        XmlPullParser xpp = getContext().getResources().getXml(localesConfigId);
+        try {
+            while (xpp.getEventType() != XmlPullParser.END_DOCUMENT) {
+                if (xpp.getEventType() == XmlPullParser.START_TAG) {
+                    if ("locale".equals(xpp.getName()) && xpp.getAttributeCount() > 0 && xpp.getAttributeName(0).equals("name")) {
+                        localeList.add(xpp.getAttributeValue(0));
+                    }
+                }
+                xpp.next();
+            }
+        } catch (IOException | XmlPullParserException e) {
+            Log.e(TAG, "Could not load locales: " + e.getMessage());
+        }
+        Optional<String> locales = localeList.stream().reduce((s1, s2) -> s1 + "," + s2);
+        return locales
+                .map(LocaleList::forLanguageTags)
+                .orElseGet(LocaleList::getEmptyLocaleList);
+    }
 }