Small improvements

app/src/main/java/eu/faircode/email/ActivityBilling.java

@@ -153,7 +153,10 @@ abstract class ActivityBilling extends ActivityBase implements PurchasesUpdatedL
             String expected = getResponse();
             if (expected.equals(response)) {
                 SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
-                prefs.edit().putBoolean("pro", true).apply();
+                prefs.edit()
+                        .putBoolean("pro", true)
+                        .putBoolean("play_store", false)
+                        .apply();
                 Log.i("Response valid");
                 Snackbar snackbar = Snackbar.make(getVisibleView(), R.string.title_pro_valid, Snackbar.LENGTH_LONG);
                 snackbar.setAction(R.string.title_check, new View.OnClickListener() {
@@ -236,7 +239,8 @@ abstract class ActivityBilling extends ActivityBase implements PurchasesUpdatedL
         if (purchases != null) {
             SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
             SharedPreferences.Editor editor = prefs.edit();
-            editor.remove("pro");
+            if (prefs.getBoolean("play_store", true))
+                editor.remove("pro");
 
             for (Purchase purchase : purchases)
                 try {

app/src/main/java/eu/faircode/email/FragmentMessages.java

@@ -857,7 +857,7 @@ public class FragmentMessages extends FragmentBase {
         }
     };
 
-    SwipeListener swipeListener = new SwipeListener(getContext(), new SwipeListener.ISwipeListener() {
+    private SwipeListener swipeListener = new SwipeListener(getContext(), new SwipeListener.ISwipeListener() {
         @Override
         public boolean onSwipeRight() {
             if (previous != null)
@@ -2112,8 +2112,9 @@ public class FragmentMessages extends FragmentBase {
                         int count = 0;
                         for (int i = 0; i < messages.size(); i++) {
                             TupleMessageEx message = messages.get(i);
-                            if (message != null &&
-                                    !EntityFolder.ARCHIVE.equals(message.folderType) &&
+                            if (message == null)
+                                continue;
+                            if (!EntityFolder.ARCHIVE.equals(message.folderType) &&
                                     !EntityFolder.SENT.equals(message.folderType) &&
                                     !EntityFolder.TRASH.equals(message.folderType) &&
                                     !EntityFolder.JUNK.equals(message.folderType))