ReorderableListView :Multiple widgets used the same GlobalKey

android dart flutter material-design

3,087

For the future visitors if anybody would have the same problem then this solved my problem well .Github issue link

I changed the onReorder method to the below one . Basically I delayed the process by 100 milliseconds and it worked fine.

onReorder: (oldIndex, newIndex) {
          if (newIndex > list.length) newIndex = list.length;
          if (oldIndex < newIndex) newIndex--;


          Future.delayed(Duration(milliseconds: 100), (){
            setState(() {
              final Widget item = list.removeAt(oldIndex);
              list.insert(newIndex, item);
            });
          });
        },

3,087

Author by

Jagraj Singh

Knowledge Seeker. Bachelors of Technology in Computer Science. Also a freelance Software Developer. ♥️ 3D Printing and Internet of Things ♥️

Updated on December 08, 2022

Comments

Jagraj Singh over 1 year

I am working on an application in which a page uses a ReorderableListView widget. While dragging upward a Tile I am getting an error but when I drag any Tile downward it's working fine. The error is about Global Key used by multiple widgets but all the keys are different from each other. Any help would be appreciated. Thanks in advance. The Video link and Code is attached for the reference.

class GurmatLekh extends StatefulWidget {
  @override
  _GurmatLekhState createState() => _GurmatLekhState();
}

Widget listTile(
    { String key, Widget widget, String title}) {
  BuildContext context;
  return Container(
      key: Key(key),
      decoration: BoxDecoration(
          color: theme == 1 ? Colors.black : Colors.white,
          borderRadius: BorderRadius.circular(5),
          border: Border.all(color: Colors.lightBlue)),
      child: ListTile(
        onTap: () => Navigator.of(context)
            .push(MaterialPageRoute(builder: (_) => widget)),
        title: Text(
          title,
          style: TextStyle(
              color: theme == 0 ? Colors.black : Colors.white,
              fontFamily: "GurbaniAkhar",
              fontSize: 20.0),
        ),
      ));
}

class _GurmatLekhState extends State<GurmatLekh> {
  List<Widget> list = [
    listTile(key: "1", title: "1", widget: listTile1()),//listTile1 is the next Page.
    listTile(key: "2", title: "2", widget: listTile2()),//listTile2 is the next Page.
    listTile(key: "3", title: "3", widget: listTile3()),//listTile3 is the next Page.
    listTile(key: "4", title: "4", widget: listTile4()),//listTile4 is the next Page.
    listTile(key: "5", title: "5", widget: listTile5()),//listTile5 is the next Page.
  ];

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        backgroundColor: Color.fromRGBO(50, 42, 57, 1.0),
        appBar: AppBar(
          backgroundColor: Colors.lightBlue,
          centerTitle: true,
          title: Text(
            "gurmiq lyK", //gurmat lekh
            style: TextStyle(
                fontFamily: "Prabhki",
                fontSize: 27.0,
                fontWeight: FontWeight.bold),
          ),
        ),
        body: Stack(children: <Widget>[
          Opacity(
            opacity: 0.6,
            child: Container(
              color: Colors.teal,
            ),
          ),
          ReorderableListView(
            children: list,
            onReorder: (oldIndex, newIndex) {
              print(oldIndex);
              print(newIndex);

              if (newIndex > list.length) newIndex = list.length;
              if (oldIndex < newIndex) newIndex--;

              Widget widget = list[oldIndex];
              list.remove(widget);
              list.insert(newIndex, widget);
              setState(() {});
            },
          ),
        ]));
  }
}

Here is the video for my error

This is the error coming in the console of AS

I/flutter ( 6893): The following assertion was thrown building LongPressDraggable<Key>(state:
I/flutter ( 6893): _DraggableState<Key>#a6138):
I/flutter ( 6893): Multiple widgets used the same GlobalKey.
I/flutter ( 6893): The key [GlobalObjectKey ValueKey<String>#c5ac5] was used by multiple widgets. The parents of those
I/flutter ( 6893): widgets were:
I/flutter ( 6893): - Listener(listeners: [down], behavior: deferToChild, renderObject: RenderPointerListener#ef3da
I/flutter ( 6893):   relayoutBoundary=up4 NEEDS-LAYOUT)
I/flutter ( 6893): - Listener(listeners: [down], behavior: deferToChild, renderObject: RenderPointerListener#78330
I/flutter ( 6893):   relayoutBoundary=up3)
I/flutter ( 6893): A GlobalKey can only be specified on one widget at a time in the widget tree.
I/flutter ( 6893): 
I/flutter ( 6893): When the exception was thrown, this was the stack:
I/flutter ( 6893): #0      GlobalKey._debugReserveFor.<anonymous closure> (package:flutter/src/widgets/framework.dart:172:11)
I/flutter ( 6893): #1      GlobalKey._debugReserveFor (package:flutter/src/widgets/framework.dart:190:6)
I/flutter ( 6893): #2      Element.updateChild.<anonymous closure> (package:flutter/src/widgets/framework.dart:2724:13)
I/flutter ( 6893): #3      Element.updateChild (package:flutter/src/widgets/framework.dart:2727:6)
I/flutter ( 6893): #4      SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4867:14)
I/flutter ( 6893): #5      Element.updateChild (package:flutter/src/widgets/framework.dart:2742:15)
I/flutter ( 6893): #6      ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3732:16)
I/flutter ( 6893): #7      Element.rebuild (package:flutter/src/widgets/framework.dart:3547:5)
I/flutter ( 6893): #8      StatefulElement.update (package:flutter/src/widgets/framework.dart:3878:5)
I/flutter ( 6893): #9      Element.updateChild (package:flutter/src/widgets/framework.dart:2742:15)
I/flutter ( 6893): #10     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4867:14)
I/flutter ( 6893): #11     Element.updateChild (package:flutter/src/widgets/framework.dart:2742:15)
I/flutter ( 6893): #12     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3732:16)
I/flutter ( 6893): #13     Element.rebuild (package:flutter/src/widgets/framework.dart:3547:5)
I/flutter ( 6893): #14     StatefulElement.update (package:flutter/src/widgets/framework.dart:3878:5)
I/flutter ( 6893): #15     Element.updateChild (package:flutter/src/widgets/framework.dart:2742:15)
I/flutter ( 6893): #16     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3732:16)
I/flutter ( 6893): #17     Element.rebuild (package:flutter/src/widgets/framework.dart:3547:5)
I/flutter ( 6893): #18     StatelessElement.update (package:flutter/src/widgets/framework.dart:3781:5)
I/flutter ( 6893): #19     Element.updateChild (package:flutter/src/widgets/framework.dart:2742:15)
I/flutter ( 6893): #20     RenderObjectElement.updateChildren (package:flutter/src/widgets/framework.dart:4585:32)
I/flutter ( 6893): #21     MultiChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4975:17)
I/flutter ( 6893): #22     Element.updateChild (package:flutter/src/widgets/framework.dart:2742:15)
I/flutter ( 6893): #23     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4867:14)
I/flutter ( 6893): #24     Element.updateChild (package:flutter/src/widgets/framework.dart:2742:15)
I/flutter ( 6893): #25     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3732:16)
I/flutter ( 6893): #26     Element.rebuild (package:flutter/src/widgets/framework.dart:3547:5)
I/flutter ( 6893): #27     ProxyElement.update (package:flutter/src/widgets/framework.dart:3990:5)
I/flutter ( 6893): #28     Element.updateChild (package:flutter/src/widgets/framework.dart:2742:15)
I/flutter ( 6893): #29     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4867:14)
I/flutter ( 6893): #30     Element.updateChild (package:flutter/src/widgets/framework.dart:2742:15)
I/flutter ( 6893): #31     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4867:14)
I/flutter ( 6893): #32     Element.updateChild (package:flutter/src/widgets/framework.dart:2742:15)
I/flutter ( 6893): #33     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4867:14)
I/flutter ( 6893): #34     Element.updateChild (package:flutter/src/widgets/framework.dart:2742:15)
I/flutter ( 6893): #35     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4867:14)
I/flutter ( 6893): #36     Element.updateChild (package:flutter/src/widgets/framework.dart:2742:15)
I/flutter ( 6893): #37     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3732:16)
I/flutter ( 6893): #38     Element.rebuild (package:flutter/src/widgets/framework.dart:3547:5)
I/flutter ( 6893): #39     StatefulElement.update (package:flutter/src/widgets/framework.dart:3878:5)
I/flutter ( 6893): #40     Element.updateChild (package:flutter/src/widgets/framework.dart:2742:15)
I/flutter ( 6893): #41     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4867:14)
I/flutter ( 6893): #42     Element.updateChild (package:flutter/src/widgets/framework.dart:2742:15)
I/flutter ( 6893): #43     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4867:14)
I/flutter ( 6893): #44     Element.updateChild (package:flutter/src/widgets/framework.dart:2742:15)
I/flutter ( 6893): #45     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4867:14)
I/flutter ( 6893): #46     Element.updateChild (package:flutter/src/widgets/framework.dart:2742:15)
I/flutter ( 6893): #47     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4867:14)
I/flutter ( 6893): #48     Element.updateChild (package:flutter/src/widgets/framework.dart:2742:15)
I/flutter ( 6893): #49     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3732:16)
I/flutter ( 6893): #50     Element.rebuild (package:flutter/src/widgets/framework.dart:3547:5)
I/flutter ( 6893): #51     StatelessElement.update (package:flutter/src/widgets/framework.dart:3781:5)
I/flutter ( 6893): #52     Element.updateChild (package:flutter/src/widgets/framework.dart:2742:15)
I/flutter ( 6893): #53     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3732:16)
I/flutter ( 6893): #54     Element.rebuild (package:flutter/src/widgets/framework.dart:3547:5)
I/flutter ( 6893): #55     StatefulElement.update (package:flutter/src/widgets/framework.dart:3878:5)
I/flutter ( 6893): #56     Element.updateChild (package:flutter/src/widgets/framework.dart:2742:15)
I/flutter ( 6893): #57     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3732:16)
I/flutter ( 6893): #58     Element.rebuild (package:flutter/src/widgets/framework.dart:3547:5)
I/flutter ( 6893): #59     StatefulElement.update (package:flutter/src/widgets/framework.dart:3878:5)
I/flutter ( 6893): #60     Element.updateChild (package:flutter/src/widgets/framework.dart:2742:15)
I/flutter ( 6893): #61     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3732:16)
I/flutter ( 6893): #62     Element.rebuild (package:flutter/src/widgets/framework.dart:3547:5)
I/flutter ( 6893): #63     StatelessElement.update (package:flutter/src/widgets/framework.dart:3781:5)
I/flutter ( 6893): #64     Element.updateChild (package:flutter/src/widgets/framework.dart:2742:15)
I/flutter ( 6893): #65     _LayoutBuilderElement._layout.<anonymous closure> (package:flutter/src/widgets/layout_builder.dart:118:18)
I/flutter ( 6893): #66     BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:2266:19)
I/flutter ( 6893): #67     _LayoutBuilderElement._layout (package:flutter/src/widgets/layout_builder.dart:107:11)
I/flutter ( 6893): #68     RenderObject.invokeLayoutCallback.<anonymous closure> (package:flutter/src/rendering/object.dart:1730:58)
I/flutter ( 6893): #69     PipelineOwner._enableMutationsToDirtySubtrees (package:flutter/src/rendering/object.dart:799:15)
I/flutter ( 6893): #70     RenderObject.invokeLayoutCallback (package:flutter/src/rendering/object.dart:1730:13)
I/flutter ( 6893): #71     _RenderLayoutBuilder.performLayout (package:flutter/src/widgets/layout_builder.dart:205:5)
I/flutter ( 6893): #72     RenderObject.layout (package:flutter/src/rendering/object.dart:1634:7)
I/flutter ( 6893): #73     RenderStack.performLayout (package:flutter/src/rendering/stack.dart:510:15)
I/flutter ( 6893): #74     RenderObject.layout (package:flutter/src/rendering/object.dart:1634:7)
I/flutter ( 6893): #75     __RenderTheatre&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:104:13)
I/flutter ( 6893): #76     RenderObject.layout (package:flutter/src/rendering/object.dart:1634:7)
I/flutter ( 6893): #77     RenderStack.performLayout (package:flutter/src/rendering/stack.dart:510:15)
I/flutter ( 6893): #78     RenderObject.layout (package:flutter/src/rendering/object.dart:1634:7)
I/flutter ( 6893): #79     MultiChildLayoutDelegate.layoutChild (package:flutter/src/rendering/custom_layout.dart:142:11)
I/flutter ( 6893): #80     _ScaffoldLayout.performLayout (package:flutter/src/material/scaffold.dart:339:7)
I/flutter ( 6893): #81     MultiChildLayoutDelegate._callPerformLayout (package:flutter/src/rendering/custom_layout.dart:212:7)
I/flutter ( 6893): #82     RenderCustomMultiChildLayoutBox.performLayout (package:flutter/src/rendering/custom_layout.dart:356:14)
I/flutter ( 6893): #83     RenderObject._layoutWithoutResize (package:flutter/src/rendering/object.dart:1509:7)
I/flutter ( 6893): #84     PipelineOwner.flushLayout (package:flutter/src/rendering/object.dart:768:18)
I/flutter ( 6893): #85     _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding&PaintingBinding&SemanticsBinding&RendererBinding.drawFrame (package:flutter/src/rendering/binding.dart:281:19)
I/flutter ( 6893): #86     _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding&PaintingBinding&SemanticsBinding&RendererBinding&WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:677:13)
I/flutter ( 6893): #87     _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding&PaintingBinding&SemanticsBinding&RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:219:5)
I/flutter ( 6893): #88     _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:990:15)
I/flutter ( 6893): #89     _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:930:9)
I/flutter ( 6893): #90     _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding._handleDrawFrame (package:flutter/src/scheduler/binding.dart:842:5)
I/flutter ( 6893): #91     _invoke (dart:ui/hooks.dart:154:13)
I/flutter ( 6893): #92     _drawFrame (dart:ui/hooks.dart:143:3)
I/flutter ( 6893): ════════════════════════════════════════════════════════════════════════════════════════════════════

leodriesch over 5 years

can you post your listTile() method?
Jagraj Singh over 5 years

I have updated my code . Please check and help me!
Günter Zöchbauer over 5 years

See also github.com/flutter/flutter/issues/21829, github.com/flutter/flutter/issues/24660
Jagraj Singh over 5 years

@GünterZöchbauer Thanks Man that solved my issue, but i dont know why , if you can explain it . Thanks in advance.
Günter Zöchbauer over 5 years

Not sure what you mean with "that" but it looks like there is actually an issue in Flutter and you might have applied a workaround.

Günter Zöchbauer over 5 years

That means that Flutter needs an extra build cycle to update its keys in cache to not cause conflicts.
Sahaj Rana over 4 years

I works! and you could set it to 20 milliseconds as well. (it removes the lag).
lacas over 4 years

What about if I am in a dialog instead of statefulwidget? How can call setState there?