2020-02-21 20:39:26.182 13086-13166/ E/Unity: NullReferenceException: Object reference not set to an instance of an object
at Unity.UIWidgets.engine.UIWidgetsPanel._handleViewMetricsChanged (System.String method, System.Collections.Generic.List1[T] args) [0x00001] in /Users/wenjie.ma/uartapp/ArtApp/Packages/com.unity.uiwidgets/Runtime/engine/UIWidgetsPanel.cs:137 at (wrapper delegate-invoke) <Module>.invoke_void_string_List1(string,System.Collections.Generic.List`1)
at Unity.UIWidgets.engine.UIWidgetsMessageManager.OnUIWidgetsMethodMessage (System.String message) [0x00080] in /Users/wenjie.ma/uartapp/ArtApp/Packages/com.unity.uiwidgets/Runtime/engine/UIWidgetsMessageManager.cs:88
2020-02-21 20:39:26.182 13086-13166/ E/Unity: NullReferenceException: Object reference not set to an instance of an object at Unity.UIWidgets.engine.UIWidgetsPanel._handleViewMetricsChanged (System.String method, System.Collections.Generic.List(string,System.Collections.Generic.List`1)
at Unity.UIWidgets.engine.UIWidgetsMessageManager.OnUIWidgetsMethodMessage (System.String message) [0x00080] in /Users/wenjie.ma/uartapp/ArtApp/Packages/com.unity.uiwidgets/Runtime/engine/UIWidgetsMessageManager.cs:88
1[T] args) [0x00001] in /Users/wenjie.ma/uartapp/ArtApp/Packages/com.unity.uiwidgets/Runtime/engine/UIWidgetsPanel.cs:137 at (wrapper delegate-invoke) <Module>.invoke_void_string_List
1