Fixed race condition

FAQ.md

@@ -82,7 +82,6 @@ Related questions:
 * A preview of a message text doesn't (always) appear on Samsung watches because [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) seem to be ignored. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, and Mi band 3 wearables. See also [this FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
-* The expanded/collapsed state and the visibility of the message body are sometimes not in sync. This seems to be caused by a bug in the AndroidX ConstraintLayout.
 
 ## Planned features
 

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

@@ -3529,16 +3529,6 @@ public class AdapterMessage extends RecyclerView.Adapter<AdapterMessage.ViewHold
             else {
                 boolean expanded = !properties.getValue("expanded", message.id);
 
-                // Prevent flicker
-                if (expanded && message.accountAutoSeen && !message.folderReadOnly) {
-                    message.unseen = 0;
-                    message.ui_seen = true;
-                    message.visible_unseen = 0;
-                    message.ui_unsnoozed = false;
-                }
-                properties.setValue("expanded", message.id, expanded);
-                bindTo(message, expanded);
-
                 properties.setExpanded(message, expanded);
 
                 // Needed to scroll to item after collapsing other items
@@ -4288,10 +4278,9 @@ public class AdapterMessage extends RecyclerView.Adapter<AdapterMessage.ViewHold
                     if (amessage == null || !amessage.id.equals(id))
                         return;
 
-                    properties.setExpanded(message, false);
                     message.ui_seen = args.getBoolean("seen");
                     message.unseen = (message.ui_seen ? 0 : message.count);
-                    bindTo(message, false);
+                    properties.setExpanded(message, false);
                 }
 
                 @Override

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

@@ -1653,6 +1653,19 @@ public class FragmentMessages extends FragmentBase implements SharedPreferences.
 
             setValue("expanded", message.id, value);
 
+            final int p = adapter.getPositionForKey(message.id);
+            if (p != NO_POSITION)
+                rvMessage.post(new Runnable() {
+                    @Override
+                    public void run() {
+                        try {
+                            adapter.notifyItemChanged(p);
+                        } catch (Throwable ex) {
+                            Log.e(ex);
+                        }
+                    }
+                });
+
             // Collapse other messages
             SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(getContext());
             boolean expand_all = prefs.getBoolean("expand_all", false);