Looking up a deactivated widget's ancestor is unsafe. ..

[Xgamefactory]

https://stackoverflow.com/questions/53071170/an-error-happened-while-using-swipper-in-flutter

I/flutter (18225): #4      ScrollActivity.dispatchScrollEndNotification 
package:flutter/…/widgets/scroll_activity.dart:106
I/flutter (18225): #5      ScrollPosition.didEndScroll 
package:flutter/…/widgets/scroll_position.dart:670
I/flutter (18225): #6      ScrollPosition.beginActivity (package:flutter/src/widgets/scro
I/flutter (18225): Looking up a deactivated widget's ancestor is unsafe.
I/flutter (18225): At this point the state of the widget's element tree is no longer stable.