Cannot scroll vertical anymore

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

@@ -834,8 +834,13 @@ abstract class ActivityBase extends AppCompatActivity implements SharedPreferenc
         return super.shouldUpRecreateTask(targetIntent);
     }
 
+    public boolean abShowing = true;
     public ValueAnimator abAnimator = null;
 
+    public boolean isActionBarShown() {
+        return abShowing;
+    }
+
     public void showActionBar(boolean show) {
         ViewGroup abv = findViewById(R.id.action_bar);
         if (abv == null) {
@@ -847,6 +852,10 @@ abstract class ActivityBase extends AppCompatActivity implements SharedPreferenc
             else
                 ab.hide();
         } else {
+            if (abShowing == show)
+                return;
+            abShowing = show;
+
             int height = Helper.getActionBarHeight(this);
             int current = abv.getLayoutParams().height;
             int target = (show ? height : 0);

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

@@ -106,6 +106,14 @@ public class FragmentBase extends Fragment {
             return null;
     }
 
+    protected boolean isActionBarShown() {
+        FragmentActivity activity = getActivity();
+        if (activity instanceof ActivityBase)
+            return ((ActivityBase) activity).isActionBarShown();
+        else
+            return false;
+    }
+
     protected void showActionBar(boolean show) {
         FragmentActivity activity = getActivity();
         if (activity instanceof ActivityBase)

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

@@ -771,6 +771,21 @@ public class FragmentMessages extends FragmentBase
                 }
             }
 
+            @Override
+            public void onLayoutCompleted(RecyclerView.State state) {
+                super.onLayoutCompleted(state);
+                if (!isActionBarShown())
+                    try {
+                        int range = computeVerticalScrollRange(state);
+                        int extend = computeVerticalScrollExtent(state);
+                        boolean canScrollVertical = (range > extend);
+                        if (!canScrollVertical) // anymore
+                            showActionBar(true);
+                    } catch (Throwable ex) {
+                        Log.e(ex);
+                    }
+            }
+
             @Override
             public void onItemsAdded(@NonNull RecyclerView recyclerView, int positionStart, int itemCount) {
                 iProperties.layoutChanged();
@@ -1122,13 +1137,17 @@ public class FragmentMessages extends FragmentBase
                     }
                 }
 
-                if (hide_toolbar && dy != 0) {
+                if (hide_toolbar && dy != 0)
-                    int range = rv.computeVerticalScrollRange();
+                    try {
-                    int extend = rv.computeVerticalScrollExtent();
+                        int range = rv.computeVerticalScrollRange();
-                    int offset = rv.computeVerticalScrollOffset();
+                        int extend = rv.computeVerticalScrollExtent();
-                    boolean canScrollVertical = (range > extend);
+                        boolean canScrollVertical = (range > extend);
-                    show = (!canScrollVertical || (offset == 0 || dy < 0));
+                        show = (!canScrollVertical ||
-                }
+                                (dy < 0 || rv.computeVerticalScrollOffset() == 0));
+                    } catch (Throwable ex) {
+                        Log.e(ex);
+                        show = true;
+                    }
             }
 
             @Override