How to find the Root GameObject a clicked UIButton is on

[technoir]

Hi,

I'm trying to find the root GameObject if a child object that has a UIButton component. When the child object is clicked, I would like to record the root GameObject. I am using the following which brings up an error;

1. public GameObject RootGameObject;
2.  
3.     void OnClick()
4.     {
5.         UIButton btn = UIButton.current;
6.  
7.         RootGameObject = btn.transform.root.gameObject;
8.  
9.       //  Debug.Log(UIButton.current.name);
10.     }
11.  

The error is:

1. NullReferenceException: Object reference not set to an instance of an object
2. KeepTrackOfOpenWindow.OnClick () (at Assets/Khoda/Scripts/Q&A/KeepTrackOfOpenWindow.cs:12)
3. UnityEngine.GameObject:SendMessage(String, Object, SendMessageOptions)
4. UICamera:Notify(GameObject, String, Object) (at Assets/NGUI/Scripts/UI/UICamera.cs:1065)
5. UICamera:ProcessTouch(Boolean, Boolean) (at Assets/NGUI/Scripts/UI/UICamera.cs:1808)
6. UICamera:ProcessMouse() (at Assets/NGUI/Scripts/UI/UICamera.cs:1402)
7. UICamera:ProcessTouches() (at Assets/NGUI/Scripts/UI/UICamera.cs:1474)
8. UICamera:Update() (at Assets/NGUI/Scripts/UI/UICamera.cs:1221)
9.  
10.  

Any help wuld be great - Thanks

[PoN]

1. RootGameObject = btn.transform.parent.gameObject;
2.