save fragment state when changing theme/langugage

closes #2782
// FREEBIE

src/org/thoughtcrime/securesms/ApplicationPreferencesActivity.java

@@ -18,6 +18,7 @@ package org.thoughtcrime.securesms;
 
 import android.content.Intent;
 import android.content.SharedPreferences;
+import android.os.Build.VERSION;
 import android.os.Bundle;
 import android.preference.Preference;
 import android.support.annotation.NonNull;
@@ -70,7 +71,10 @@ public class ApplicationPreferencesActivity extends PassphraseRequiredActionBarA
   @Override
   protected void onCreate(Bundle icicle, @NonNull MasterSecret masterSecret) {
     this.getSupportActionBar().setDisplayHomeAsUpEnabled(true);
-    initFragment(android.R.id.content, new ApplicationPreferenceFragment(), masterSecret);
+
+    if (icicle == null) {
+      initFragment(android.R.id.content, new ApplicationPreferenceFragment(), masterSecret);
+    }
   }
 
   @Override
@@ -105,9 +109,11 @@ public class ApplicationPreferencesActivity extends PassphraseRequiredActionBarA
   @Override
   public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {
     if (key.equals(TextSecurePreferences.THEME_PREF)) {
-      dynamicTheme.onResume(this);
+      if (VERSION.SDK_INT >= 11) recreate();
+      else                       dynamicTheme.onResume(this);
     } else if (key.equals(TextSecurePreferences.LANGUAGE_PREF)) {
-      dynamicLanguage.onResume(this);
+      if (VERSION.SDK_INT >= 11) recreate();
+      else                       dynamicLanguage.onResume(this);
 
       Intent intent = new Intent(this, KeyCachingService.class);
       intent.setAction(KeyCachingService.LOCALE_CHANGE_EVENT);