Hide item decorators for hidden items

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

@@ -310,7 +310,15 @@ public class FragmentMessages extends FragmentBase {
         LinearLayoutManager llm = new LinearLayoutManager(getContext());
         rvMessage.setLayoutManager(llm);
 
-        DividerItemDecoration itemDecorator = new DividerItemDecoration(getContext(), DividerItemDecoration.VERTICAL);
+        DividerItemDecoration itemDecorator = new DividerItemDecoration(getContext(), DividerItemDecoration.VERTICAL) {
+            @Override
+            public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
+                if (view.findViewById(R.id.clItem).getVisibility() == View.GONE)
+                    outRect.setEmpty();
+                else
+                    super.getItemOffsets(outRect, view, parent, state);
+            }
+        };
         itemDecorator.setDrawable(getContext().getDrawable(R.drawable.divider));
         rvMessage.addItemDecoration(itemDecorator);