commit 4cad53b47f8ce1f388fc87d863f9f32570ae3e45
Author: Leszek Koltunski <leszek@koltunski.pl>
Date:   Tue Nov 2 22:09:58 2021 +0100

    Bugfixes for crashes from Firebase.

diff --git a/src/main/java/org/distorted/tutorials/TutorialObjectLibInterface.java b/src/main/java/org/distorted/tutorials/TutorialObjectLibInterface.java
index 0499ee69..89802bed 100644
--- a/src/main/java/org/distorted/tutorials/TutorialObjectLibInterface.java
+++ b/src/main/java/org/distorted/tutorials/TutorialObjectLibInterface.java
@@ -144,7 +144,7 @@ public class TutorialObjectLibInterface implements ObjectLibInterface
      {
      TutorialActivity act = mAct.get();
      TutorialScreen state = act.getState();
-     state.addMove(act, axis, row, angle);
+     if( state!=null ) state.addMove(act, axis, row, angle);
      }
 
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