NGUI 3.0.8 fx2 null reference excpetion in UIDrawCall with fix

[kasparlund]

I got null reference on app termination i UIPanle and had to make the following fix

The fix is to check for "dc!=null" in ClearAll,  ReleaseAll, Destroy:
 
   static public void ClearAll ()
   {
      bool playing = Application.isPlaying;

      for (int i = mActiveList.size; i > 0; )
      {
         UIDrawCall dc = mActiveList[--i];
         if( dc!=null ){
            if (playing) NGUITools.SetActive(dc.gameObject, false);
            else NGUITools.DestroyImmediate(dc.gameObject);
         }
      }
      mActiveList.Clear();
   }

   static public void ReleaseAll ()
   {
      ClearAll();

      for (int i = mInactiveList.size; i > 0; )
      {
         UIDrawCall dc = mInactiveList[--i];
         if( dc!=null )
            NGUITools.DestroyImmediate(dc.gameObject);
      }
      mInactiveList.Clear();
   }

   static public void Destroy (UIDrawCall dc)
   {
      if (Application.isPlaying && dc!=null )
      {
         if (mActiveList.Remove(dc))
         {
               NGUITools.SetActive(dc.gameObject, false);
               mInactiveList.Add(dc);
         }
      }
      else if( dc!=null )
      {
         mActiveList.Remove(dc);
         NGUITools.DestroyImmediate(dc.gameObject);
      }
   }

[ArenMook]

How did you even get to the state where draw call is null? What destroyed it? Only UIDrawCall is capable of destroying draw calls, and it only always removes the draw call from the active and inactive lists.

[Dust]

How did you even get to the state where draw call is null? What destroyed it? Only UIDrawCall is capable of destroying draw calls, and it only always removes the draw call from the active and inactive lists.

I want to say I just ran into this issue and all I did was upgrade from 3.0.8 f6 to f7.  Unity 4.2.2 and device is a Nexus 5 running 4.4.2

This happens when i use the android back button to quit the app.

Unity Log Below:

I get the error itself regarding the NullRef 4 times

1. I/Unity   (24487): time to quit..
2. I/Unity   (24487): windowFocusChanged: false
3. I/Unity   (24487): onPause
4. I/Unity   (24487): NullReferenceException
5. I/Unity   (24487):   at UnityEngine.Component.get_gameObject () [0x00000] in <filename unknown>:0
6. I/Unity   (24487):   at UIDrawCall.Destroy (.UIDrawCall dc) [0x0000a] in C:\Projects\GCSlotzMW\Assets\NGUI\Scripts\Internal\UIDrawCall.cs:693
7. I/Unity   (24487):   at UIPanel.OnDisable () [0x00007] in C:\Projects\GCSlotzMW\Assets\NGUI\Scripts\UI\UIPanel.cs:712

If i modify the Destroy() part to check for dc != null then i end up with:

1. I/Unity   (24816): time to quit..
2. I/Unity   (24816): windowFocusChanged: false
3. I/Unity   (24816): onPause
4. I/Unity   (24816): NullReferenceException
5. I/Unity   (24816):   at UnityEngine.Component.get_gameObject () [0x00000] in <filename unknown>:0
6. I/Unity   (24816):   at UIDrawCall.ClearAll () [0x00026] in C:\Projects\GCSlotzMW\Assets\NGUI\Scripts\Internal\UIDrawCall.cs:651
7. I/Unity   (24816):   at UIDrawCall.ReleaseAll () [0x00000] in C:\Projects\GCSlotzMW\Assets\NGUI\Scripts\Internal\UIDrawCall.cs:663
8. I/Unity   (24816):   at UIPanel.OnDisable () [0x00054] in C:\Projects\GCSlotzMW\Assets\NGUI\Scripts\UI\UIPanel.cs:718

If i then modify the ClearAll() part to check for dc != null then i end up with:

1. I/Unity   (25112): time to quit..
2. I/Unity   (25112): windowFocusChanged: false
3. I/Unity   (25112): onPause
4. I/Unity   (25112): NullReferenceException
5. I/Unity   (25112):   at UnityEngine.Component.get_gameObject () [0x00000] in <filename unknown>:0
6. I/Unity   (25112):   at UIDrawCall.ReleaseAll () [0x00025] in C:\Projects\GCSlotzMW\Assets\NGUI\Scripts\Internal\UIDrawCall.cs:671
7. I/Unity   (25112):   at UIPanel.OnDisable () [0x00054] in C:\Projects\GCSlotzMW\Assets\NGUI\Scripts\UI\UIPanel.cs:718

And then we modify the ReleaseAll() part to check for dc != null and i end up with no errors:

[ArenMook]

Did you follow the NGUI upgrade instructions? I can see something like this happening if you didn't.

Restart Unity. Does it still occur?