Show if primary account is connected

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

@@ -80,6 +80,7 @@ public class FragmentMessages extends FragmentEx {
     private String search = null;
 
     private long primary = -1;
+    private boolean connected = false;
     private AdapterMessage adapter;
 
     private AdapterMessage.ViewType viewType;
@@ -400,6 +401,7 @@ public class FragmentMessages extends FragmentEx {
             @Override
             public void onChanged(EntityAccount account) {
                 primary = (account == null ? -1 : account.id);
+                connected = (account != null && "connected".equals(account.state));
                 getActivity().invalidateOptionsMenu();
             }
         });
@@ -587,6 +589,7 @@ public class FragmentMessages extends FragmentEx {
         menu.findItem(R.id.menu_search).setVisible(folder >= 0 && search == null);
         menu.findItem(R.id.menu_sort_on).setVisible(TextUtils.isEmpty(search));
         menu.findItem(R.id.menu_folders).setVisible(primary >= 0);
+        menu.findItem(R.id.menu_folders).setIcon(connected ? R.drawable.baseline_folder_24 : R.drawable.baseline_folder_open_24);
 
         SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(getContext());
         String sort = prefs.getString("sort", "time");

app/src/main/res/drawable/baseline_folder_open_24.xml

@@ -0,0 +1,10 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="24dp"
+        android:height="24dp"
+        android:viewportWidth="24.0"
+        android:viewportHeight="24.0"
+        android:tint="?attr/colorControlNormal">
+    <path
+        android:fillColor="@android:color/white"
+        android:pathData="M20,6h-8l-2,-2L4,4c-1.1,0 -1.99,0.9 -1.99,2L2,18c0,1.1 0.9,2 2,2h16c1.1,0 2,-0.9 2,-2L22,8c0,-1.1 -0.9,-2 -2,-2zM20,18L4,18L4,8h16v10z"/>
+</vector>

app/src/main/res/menu/menu_list.xml

@@ -31,7 +31,7 @@
 
     <item
         android:id="@+id/menu_folders"
-        android:icon="@drawable/baseline_folder_24"
+        android:icon="@drawable/baseline_folder_open_24"
         android:title="@string/title_folder_primary"
         app:showAsAction="ifRoom" />
 </menu>