Ndtyjky

I am using a StatefulBuilder widget to update my values and it all works fine.

StatefulBuilder(

      builder: (BuildContext context, StateSetter setState) {

   return Mywidget();

});

Since this widget is in a Tab view, when I scroll to the next tab, I get the below exception in console.

E/flutter ( 7147): [ERROR:flutter/shell/common/shell.cc(188)] Dart Error: Unhandled exception:

E/flutter ( 7147): setState() called after dispose(): _StatefulBuilderState#09a22(lifecycle state: defunct, not mounted)

E/flutter ( 7147): This error happens if you call setState() on a State object for a widget that no longer appears in the widget tree (e.g., whose parent widget no longer includes the widget in its build). This error can occur when code calls setState() from a timer or an animation callback. The preferred solution is to cancel the timer or stop listening to the animation in the dispose() callback. Another solution is to check the "mounted" property of this object before calling setState() to ensure the object is still in the tree.

E/flutter ( 7147): This error might indicate a memory leak if setState() is being called because another object is retaining a reference to this State object after it has been removed from the tree. To avoid memory leaks, consider breaking the reference to this object during dispose().

E/flutter ( 7147): #0      State.setState.<anonymous closure> (package:flutter/src/widgets/framework.dart:1097:9)

E/flutter ( 7147): #1      State.setState (package:flutter/src/widgets/framework.dart:1123:6)

E/flutter ( 7147): #2      ImageItem.actionColumn.<anonymous closure>.<anonymous closure> (package:silkthread/widgets/image_item.dart:197:19)

E/flutter ( 7147): #3      _RootZone.runUnary (dart:async/zone.dart:1379:54)

E/flutter ( 7147): #4      _FutureListener.handleValue (dart:async/future_impl.dart:129:18)

E/flutter ( 7147): #5      Future._propagateToListeners.handleValueCallback (dart:async/future_impl.dart:642:45)

E/flutter ( 7147): #6      Future._propagateToListeners (dart:async/future_impl.dart:671:32)

E/flutter ( 7147): #7      Future._complete (dart:async/future_impl.dart:476:7)

E/flutter ( 7147): #8      _SyncCompleter.complete (dart:async/future_impl.dart:51:12)

E/flutter ( 7147): #9      _RootZone.runUnary (dart:async/zone.dart:1379:54)

E/flutter ( 7147): #10     _FutureListener.handleValue (dart:async/future_impl.dart:129:18)

E/flutter ( 7147): #11     Future._propagateToListeners.handleValueCallback (dart:async/future_impl.dart:642:45)

E/flutter ( 7147): #12     Future._propagateToListeners (dart:async/future_impl.dart:671:32)

E/flutter ( 7147): #13     Future._complete (dart:async/future_impl.dart:476:7)

E/flutter ( 7147): #14     _SyncCompleter.complete (dart:async/future_impl.dart:51:12)

E/flutter ( 7147): #15     _AsyncAwaitCompleter.complete.<anonymous closure> (dart:async/runtime/libasync_patch.dart:33:20)

E/flutter ( 7147): #16     _microtaskLoop (dart:async/schedule_microtask.dart:41:21)

E/flutter ( 7147): #17     _startMicrotaskLoop (dart:async/schedule_microtask.dart:50:5)

Since the page which has StatefulBuilder widget is a StatelessWidget, I can't call dispose() method.

So while using StatefulBuilder how can I avoid this exception?

Edit:
I am trying something same as mentioned in the article https://medium.com/flutter-community/stateful-widgets-be-gone-stateful-builder-a67f139725a0.

class ImageItem extends StatelessWidget {

  @override

  Widget build(BuildContext context) {



      return StatefulBuilder(

           builder: (BuildContext context, StateSetter setState) {

               setState(() {

                 likesCount = post.likesCount;

               });



              return ActionChip(label: Text(likesCount);

      });

  }

}

Wrap your code

if(mounted) {

  setState(() { ... });

}

to avoid setState() being called when the widget is not mounted.