hide Languages pref on >= android-24

Android 24 and later provides tons of languages, and a way to rank
multiple languages instead of choosing one.  The Languages pref is a
big hack and can be problematic, so its better to disable it when its
not needed.  This will make it so it is no longer possible to set
F-Droid to a language that the system does not support.

#943

app/src/main/java/org/fdroid/fdroid/Languages.java

@@ -117,6 +117,11 @@ public final class Languages {
 
     @TargetApi(17)
     public static void setLanguage(final ContextWrapper contextWrapper, String language, boolean refresh) {
+        if (Build.VERSION.SDK_INT >= 24) {
+            Utils.debugLog(TAG, "Languages.setLanguage() ignored on >= android-24");
+            Preferences.get().clearLanguage();
+            return;
+        }
         if (locale != null && TextUtils.equals(locale.getLanguage(), language) && (!refresh)) {
             return; // already configured
         } else if (language == null || language.equals(USE_SYSTEM_DEFAULT)) {
@@ -148,6 +153,10 @@ public final class Languages {
      * @param activity the {@code Activity} to force reload
      */
     public static void forceChangeLanguage(Activity activity) {
+        if (Build.VERSION.SDK_INT >= 24) {
+            Utils.debugLog(TAG, "Languages.forceChangeLanguage() ignored on >= android-24");
+            return;
+        }
         Intent intent = activity.getIntent();
         if (intent == null) { // when launched as LAUNCHER
             return;
@@ -159,18 +168,6 @@ public final class Languages {
         activity.overridePendingTransition(0, 0);
     }
 
-    /**
-     * @return the name of the language based on the locale.
-     */
-    public String getName(String locale) {
-        String ret = nameMap.get(locale);
-        // if no match, try to return a more general name (i.e. English for en_IN)
-        if (ret == null && locale.contains("_")) {
-            ret = nameMap.get(locale.split("_")[0]);
-        }
-        return ret;
-    }
-
     /**
      * @return an array of the names of all the supported languages, sorted to
      * match what is returned by {@link Languages#getSupportedLocales()}.
@@ -179,19 +176,6 @@ public final class Languages {
         return nameMap.values().toArray(new String[nameMap.size()]);
     }
 
-    public int getPosition(Locale locale) {
-        String localeName = locale.getLanguage();
-        int i = 0;
-        for (String key : nameMap.keySet()) {
-            if (TextUtils.equals(key, localeName)) {
-                return i;
-            } else {
-                i++;
-            }
-        }
-        return -1;
-    }
-
     /**
      * @return sorted list of supported locales.
      */

app/src/main/java/org/fdroid/fdroid/views/fragments/PreferencesFragment.java

@@ -65,10 +65,15 @@ public class PreferencesFragment extends PreferenceFragment
         updatePrivilegedExtensionPref = findPreference(Preferences.PREF_UNINSTALL_PRIVILEGED_APP);
 
         AppCompatListPreference languagePref = (AppCompatListPreference) findPreference(Preferences.PREF_LANGUAGE);
-        Languages languages = Languages.get(getActivity());
+        if (Build.VERSION.SDK_INT >= 24) {
-        languagePref.setDefaultValue(Languages.USE_SYSTEM_DEFAULT);
+            PreferenceCategory category = (PreferenceCategory) findPreference("pref_category_display");
-        languagePref.setEntries(languages.getAllNames());
+            category.removePreference(languagePref);
-        languagePref.setEntryValues(languages.getSupportedLocales());
+        } else {
+            Languages languages = Languages.get(getActivity());
+            languagePref.setDefaultValue(Languages.USE_SYSTEM_DEFAULT);
+            languagePref.setEntries(languages.getAllNames());
+            languagePref.setEntryValues(languages.getSupportedLocales());
+        }
     }
 
     private void checkSummary(String key, int resId) {
@@ -78,7 +83,9 @@ public class PreferencesFragment extends PreferenceFragment
 
     private void entrySummary(String key) {
         ListPreference pref = (ListPreference) findPreference(key);
-        pref.setSummary(pref.getEntry());
+        if (pref != null) {
+            pref.setSummary(pref.getEntry());
+        }
     }
 
     private void textSummary(String key, int resId) {

app/src/main/res/xml/preferences.xml

@@ -41,7 +41,8 @@
             android:defaultValue="true"
             android:key="updateNotify" />
     </PreferenceCategory>
-    <PreferenceCategory android:title="@string/display">
+    <PreferenceCategory android:title="@string/display"
+                        android:key="pref_category_display">
         <com.geecko.QuickLyric.view.AppCompatListPreference android:title="@string/pref_language"
             android:key="language"/>
         <com.geecko.QuickLyric.view.AppCompatListPreference android:title="@string/theme"