dart - 在 tabbar 的页面之间处理状态
问题描述
我正在开发一个应用程序，其中包含一个计时器，因此它每秒更新一次状态，但是当我们更改页面时，会发生一些状态错误
如果您对不再出现在小部件树中的小部件（例如，其父小部件不再在其构建中包含该小部件）调用 State 对象上的 setState()，则会发生此错误。当代码从计时器或动画回调中调用 setState() 时，可能会发生此错误。首选的解决方案是取消计时器或停止在 dispose() 回调中收听动画。另一种解决方案是在调用 setState() 之前检查该对象的“已安装”属性，以确保该对象仍在树中。
E/flutter (5287)：如果 setState() 被调用，此错误可能表示内存泄漏，因为另一个对象在从树中删除后保留对此 State 对象的引用。为避免内存泄漏，请考虑在 dispose() 期间中断对此对象的引用。
我真的不知道如何以及在哪里使用 dispose() 方法
错误 示例 示例
因此，请帮助我处理以前的小部件树并在我们切换屏幕时重建它。
我的代码可以分为两部分。一个包含所有内容的主页和两个触发 setstate 的计时器部分。
第一部分：
import 'package:flutter/material.dart';
import '../Theme.dart' as Theme;
import '../Components/ropSayac.dart';
import '../Components/Stackvideostile.dart';
class Ropo extends StatefulWidget {
final RopoState state = new RopoState();
void update(bool exp) {
state.change(exp);
}
RopoState createState() => state;
}
class RopoState extends State<Ropo> {
bool videomounted, expired;
int remday = 0, remhour = 0, remmin = 0, remsec = 0;
void change(bool exp) {
setState(() {
this.expired = exp;
});
}
Widget updatetimer(int rday, rhour, rmin, rsec) {
setState(() {
remday = rday;
remhour = rhour;
remmin = rmin;
remsec = rsec;
});
}
Widget sayac(BuildContext context) {
return Container(
color: Colors.black,
height: 40.0,
width: MediaQuery.of(context).size.width,
child: new Container(
margin: EdgeInsets.only(left: 15.0, right: 15.0),
child: new Row(
// mainAxisAlignment: MainAxisAlignment.center,
crossAxisAlignment: CrossAxisAlignment.center,
children: <Widget>[
new Text(
"BU HAFTAKİ RÖPORTAJA",
style: Theme.TextStyles.ropsayacc,
),
new Expanded(
flex: 1,
child: new Container(
color: Colors.black,
),
),
new Text(
"$remday : $remhour : $remmin : $remsec",
style: Theme.TextStyles.ropsayaccint,
),
],
),
),
);
}
Widget konukyazi() {
// BU HAFTAKİ KONUĞUMUZ
return new Column(
crossAxisAlignment: CrossAxisAlignment.center,
children: <Widget>[
new Text(
"BU HAFTAKİ",
style: Theme.TextStyles.koseice,
),
new Text(
"KONUĞUMUZ",
style: Theme.TextStyles.koseice,
),
],
);
}
Widget konuk(String ad, var img) {
// Yuvarlak Şeklindeki Karakter Fotoğğğğğğrafı ve Çerçevesi
return new Container(
child: new Column(
children: <Widget>[
Stack(
alignment: Alignment.center,
children: <Widget>[
Container(
width: 226.0,
height: 226.0,
decoration: new BoxDecoration(
shape: BoxShape.circle, color: Theme.Colors.pagebackground),
),
Container(
width: 215.0,
height: 215.0,
decoration: new BoxDecoration(
shape: BoxShape.circle,
image: DecorationImage(
image: new AssetImage(img),
),
),
),
],
),
new Container(
height: 12.0,
),
new Text(
ad,
style: Theme.TextStyles.kosebas,
),
],
),
);
}
void initState() {
super.initState();
}
Widget updateexpired(bool expiredd) {
setState(() {
expired = expiredd;
});
}
Widget didvideomounted() {
if (expired == true) {
return new Text("video");
} else
return new Container(
width: 226.0,
height: 226.0,
decoration: new BoxDecoration(
shape: BoxShape.circle,
border: new Border.all(
width: 5.0, color: Theme.Colors.roportajheroborder)),
);
}
Widget rendervideoorui() {
if (expired == false) {
return new Column(
children: <Widget>[
Container(
height: 8.0,
),
konukyazi(),
Container(
height: 60.0,
),
konuk("Ayşe Alan", "assets/ayseAlan.png"),
],
);
} else {
return new Text("Video Geldi :D");
// return video
}
}
Widget stackvideos() {
return new Container(
decoration: new BoxDecoration(
color: Theme.Colors.tabbarbackground,
borderRadius: BorderRadius.all(Radius.circular(8.0)),
),
margin: EdgeInsets.only(top: 40.0, bottom: 10.0),
width: 358.0,
height: 343.0,
child: Column(
children: <Widget>[
Container(
// Üstteki bar
width: 358.0,
height: 46.0,
decoration: new BoxDecoration(
color: Theme.Colors.stackvideostopbar,
borderRadius: BorderRadius.all(Radius.circular(8.0)),
boxShadow: <BoxShadow>[
new BoxShadow(
color: Colors.black12,
blurRadius: 3.0,
offset: new Offset(0.0, 7.0),
),
],
),
child: Center(
child: new Text(
"BENCE Bİ’ ÖNCEKİLERE DE GÖZ AT",
style: Theme.TextStyles.stackvideotitle,
),
),
), //üstteki bar bitti
],
),
);
}
List<String> lists = ["asdas", "adadsa"];
@override
Widget build(BuildContext context) {
return Container(
color: Theme.Colors.pagebackground,
child: new Stack(
children: <Widget>[
new Container(
margin: EdgeInsets.only(left: 0.0, top: 37.0),
child: Image.asset(
"assets/k@3x.png",
// fit: BoxFit.fill,
),
),
new Container(
child: new Column(
children: <Widget>[
RopSayac(this),
new Expanded(
child: CustomScrollView(
slivers: <Widget>[
SliverToBoxAdapter(
child: new Column(
children: <Widget>[
rendervideoorui(),
new Container(height: 40.0,),
stackvideos(),
],
),
),
],
),
),
],
),
),
//new Image.asset("name"),
],
),
);
}
}
第二部分：
import 'package:flutter/material.dart';
import '../Pages/ropor.dart';
import '../Theme.dart' as Theme;
import 'dart:async';
class RopComponent extends StatelessWidget {
@override
Widget build(BuildContext context) {
return null;
}
}
class RopSayac extends StatefulWidget {
RopoState parent;
RopSayac(this.parent);
_RopSayacState createState() => _RopSayacState(parent);
}
class _RopSayacState extends State<RopSayac> {
RopoState parent;
_RopSayacState(this.parent);
int remday = 0, remhour = 0, remmin = 0, remsec = 0;
bool expired = false;
var _now = DateTime.now();
var endpoint = DateTime.parse("2019-01-24 11:23:30");
Timer _everySecond;
final Ropo ropo = new Ropo();
Widget sayac(
BuildContext context,
) {
return Container(
color: Colors.black,
height: 40.0,
width: MediaQuery.of(context).size.width,
child: new Container(
margin: EdgeInsets.only(left: 15.0, right: 15.0),
child: new Row(
// mainAxisAlignment: MainAxisAlignment.center,
crossAxisAlignment: CrossAxisAlignment.center,
children: <Widget>[
new Text(
"BU HAFTAKİ RÖPORTAJA",
style: Theme.TextStyles.ropsayacc,
),
new Expanded(
flex: 1,
child: new Container(
color: Colors.black,
),
),
new Text(
"$remday : $remhour : $remmin : $remsec",
style: Theme.TextStyles.ropsayaccint,
),
],
),
),
);
}
@override
void initState() {
super.initState();
// RopoState bilge = new RopoState();
// eğer videonun çıkacağı tarihten öndeysek
//sayacı başlat
_everySecond = Timer.periodic(Duration(seconds: 1), (Timer t) {
if (_now.isBefore(endpoint) == true ||
_now.difference(endpoint).inSeconds == 0) {
// bilge.updateexpired(false);
expired = false;
if (this.parent.mounted) {
this.parent.setState(() {
this.parent.expired = false;
});
}
// debugPrint(_now.toString());
_now = DateTime.now();
var remai = endpoint.difference(_now);
/// bilge.updatetimer(int.parse(remai.inDays.toString()), int.parse(remai.inHours.toString()) % 24, int.parse(remai.inMinutes.toString()) % 60, int.parse(remai.inSeconds.toString()) % 60);
if (this.mounted) {
setState(() {
_now = DateTime.now();
var remai = endpoint.difference(_now);
remday = int.parse(remai.inDays.toString());
remhour = int.parse(remai.inHours.toString()) % 24;
remmin = int.parse(remai.inMinutes.toString()) % 60;
remsec = int.parse(remai.inSeconds.toString()) % 60;
});
}
} else {
debugPrint("expired");
if (this.parent.mounted) {
this.parent.setState(() {
this.parent.expired = true;
});
}
// bilge.updateexpired(false);
}
});
}
// defines a timer
@override
Widget build(BuildContext context) {
return Container(
child: sayac(context),
);
}
}
完整错误日志：
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I/flutter ( 5287): ══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════
I/flutter ( 5287): The following assertion was thrown building NotificationListener<KeepAliveNotification>:
I/flutter ( 5287): 'package:flutter/src/widgets/framework.dart': Failed assertion: line 3803 pos 12: '_state._widget ==
I/flutter ( 5287): null': is not true.
I/flutter ( 5287):
I/flutter ( 5287): Either the assertion indicates an error in the framework itself, or we should provide substantially
I/flutter ( 5287): more information in this error message to help you determine and fix the underlying cause.
I/flutter ( 5287): In either case, please report this assertion by filing a bug on GitHub:
I/flutter ( 5287): https://github.com/flutter/flutter/issues/new?template=BUG.md
I/flutter ( 5287):
I/flutter ( 5287): When the exception was thrown, this was the stack:
I/flutter ( 5287): #2 new StatefulElement (package:flutter/src/widgets/framework.dart:3803:12)
I/flutter ( 5287): #3 StatefulWidget.createElement (package:flutter/src/widgets/framework.dart:795:38)
I/flutter ( 5287): #4 Element.inflateWidget (package:flutter/src/widgets/framework.dart:2948:40)
I/flutter ( 5287): #5 Element.updateChild (package:flutter/src/widgets/framework.dart:2753:12)
I/flutter ( 5287): #6 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:4860:14)
I/flutter ( 5287): #7 Element.inflateWidget (package:flutter/src/widgets/framework.dart:2950:14)
I/flutter ( 5287): #8 Element.updateChild (package:flutter/src/widgets/framework.dart:2753:12)
I/flutter ( 5287): #9 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:4860:14)
I/flutter ( 5287): #10 Element.inflateWidget (package:flutter/src/widgets/framework.dart:2950:14)
I/flutter ( 5287): #11 Element.updateChild (package:flutter/src/widgets/framework.dart:2753:12)
I/flutter ( 5287): #12 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3732:16)
I/flutter ( 5287): #13 Element.rebuild (package:flutter/src/widgets/framework.dart:3547:5)
I/flutter ( 5287): #14 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3701:5)
I/flutter ( 5287): #15 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3696:5)
I/flutter ( 5287): #16 Element.inflateWidget (package:flutter/src/widgets/framework.dart:2950:14)
I/flutter ( 5287): #17 Element.updateChild (package:flutter/src/widgets/framework.dart:2753:12)
I/flutter ( 5287): #18 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3732:16)
I/flutter ( 5287): #19 Element.rebuild (package:flutter/src/widgets/framework.dart:3547:5)
I/flutter ( 5287): #20 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3701:5)
I/flutter ( 5287): #21 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3696:5)
I/flutter ( 5287): #22 ParentDataElement.mount (package:flutter/src/widgets/framework.dart:4047:11)
I/flutter ( 5287): #23 Element.inflateWidget (package:flutter/src/widgets/framework.dart:2950:14)
I/flutter ( 5287): #24 Element.updateChild (package:flutter/src/widgets/framework.dart:2753:12)
I/flutter ( 5287): #25 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3732:16)
I/flutter ( 5287): #26 Element.rebuild (package:flutter/src/widgets/framework.dart:3547:5)
I/flutter ( 5287): #27 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3701:5)
I/flutter ( 5287): #28 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:3848:11)
I/flutter ( 5287): #29 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3696:5)
I/flutter ( 5287): #30 Element.inflateWidget (package:flutter/src/widgets/framework.dart:2950:14)
I/flutter ( 5287): #31 Element.updateChild (package:flutter/src/widgets/framework.dart:2753:12)
I/flutter ( 5287): #32 SliverMultiBoxAdaptorElement.updateChild (package:flutter/src/widgets/sliver.dart:1028:36)
I/flutter ( 5287): #33 SliverMultiBoxAdaptorElement.createChild.<anonymous closure> (package:flutter/src/widgets/sliver.dart:1013:20)
I/flutter ( 5287): #34 BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:2266:19)
I/flutter ( 5287): #35 SliverMultiBoxAdaptorElement.createChild (package:flutter/src/widgets/sliver.dart:1006:11)
I/flutter ( 5287): #36 RenderSliverMultiBoxAdaptor._createOrObtainChild.<anonymous closure> (package:flutter/src/rendering/sliver_multi_box_adaptor.dart:274:23)
I/flutter ( 5287): #37 RenderObject.invokeLayoutCallback.<anonymous closure> (package:flutter/src/rendering/object.dart:1730:58)
I/flutter ( 5287): #38 PipelineOwner._enableMutationsToDirtySubtrees (package:flutter/src/rendering/object.dart:799:15)
I/flutter ( 5287): #39 RenderObject.invokeLayoutCallback (package:flutter/src/rendering/object.dart:1730:13)
I/flutter ( 5287): #40 RenderSliverMultiBoxAdaptor._createOrObtainChild (package:flutter/src/rendering/sliver_multi_box_adaptor.dart:263:5)
I/flutter ( 5287): #41 RenderSliverMultiBoxAdaptor.insertAndLayoutLeadingChild (package:flutter/src/rendering/sliver_multi_box_adaptor.dart:372:5)
I/flutter ( 5287): #42 RenderSliverFixedExtentBoxAdaptor.performLayout (package:flutter/src/rendering/sliver_fixed_extent_list.dart:184:31)
I/flutter ( 5287): #43 RenderObject.layout (package:flutter/src/rendering/object.dart:1634:7)
I/flutter ( 5287): #44 RenderViewportBase.layoutChildSequence (package:flutter/src/rendering/viewport.dart:405:13)
I/flutter ( 5287): #45 RenderViewport._attemptLayout (package:flutter/src/rendering/viewport.dart:1316:12)
I/flutter ( 5287): #46 RenderViewport.performLayout (package:flutter/src/rendering/viewport.dart:1234:20)
I/flutter ( 5287): #47 RenderObject._layoutWithoutResize (package:flutter/src/rendering/object.dart:1509:7)
I/flutter ( 5287): #48 PipelineOwner.flushLayout (package:flutter/src/rendering/object.dart:768:18)
I/flutter ( 5287): #49 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding&PaintingBinding&SemanticsBinding&RendererBinding.drawFrame (package:flutter/src/rendering/binding.dart:281:19)
I/flutter ( 5287): #50 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding&PaintingBinding&SemanticsBinding&RendererBinding&WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:677:13)
I/flutter ( 5287): #51 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding&PaintingBinding&SemanticsBinding&RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:219:5)
I/flutter ( 5287): #52 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:990:15)
I/flutter ( 5287): #53 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:930:9)
I/flutter ( 5287): #54 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding._handleDrawFrame (package:flutter/src/scheduler/binding.dart:842:5)
I/flutter ( 5287): #55 _invoke (dart:ui/hooks.dart:154:13)
I/flutter ( 5287): #56 _drawFrame (dart:ui/hooks.dart:143:3)
I/flutter ( 5287): (elided 2 frames from class _AssertionError)
I/flutter ( 5287): ════════════════════════════════════════════════════════════════════════════════════════════════════
I/flutter ( 5287): Another exception was thrown: 'package:flutter/src/rendering/sliver_multi_box_adaptor.dart': Failed assertion: line 235 pos 16: 'indexOf(child) > index': is not true.
I/flutter ( 5287): Another exception was thrown: 'package:flutter/src/rendering/sliver_multi_box_adaptor.dart': Failed assertion: line 235 pos 16: 'indexOf(child) > index': is not true.
I/flutter ( 5287): Another exception was thrown: 'package:flutter/src/widgets/framework.dart': Failed assertion: line 2270 pos 20: '_debugCurrentBuildTarget == context': is not true.
I/flutter ( 5287): Another exception was thrown: 'package:flutter/src/rendering/sliver_multi_box_adaptor.dart': Failed assertion: line 461 pos 12: 'child.hasSize': is not true.
I/flutter ( 5287): Another exception was thrown: 'package:flutter/src/rendering/sliver_multi_box_adaptor.dart': Failed assertion: line 574 pos 16: 'indexOf(child) == index': is not true.
I/chatty ( 5287): uid=10086(com.example.aurorav10) 1.ui identical 2 lines
I/flutter ( 5287): Another exception was thrown: 'package:flutter/src/rendering/sliver_multi_box_adaptor.dart': Failed assertion: line 574 pos 16: 'indexOf(child) == index': is not true.
E/flutter ( 5287): [ERROR:flutter/shell/common/shell.cc(184)] Dart Error: Unhandled exception:
E/flutter ( 5287): setState() called after dispose(): RopoState#2b3f4(lifecycle state: defunct)
E/flutter ( 5287): 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 ( 5287): 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 ( 5287): #0 State.setState.<anonymous closure> (package:flutter/src/widgets/framework.dart:1103:9)
E/flutter ( 5287): #1 State.setState (package:flutter/src/widgets/framework.dart:1129:6)
E/flutter ( 5287): #2 _RopSayacState.initState.<anonymous closure> (package:aurorav10/Components/ropSayac.dart:111:23)
E/flutter ( 5287): #3 _Timer._runTimers (dart:isolate/runtime/libtimer_impl.dart:382:19)
E/flutter ( 5287): #4 _Timer._handleMessage (dart:isolate/runtime/libtimer_impl.dart:416:5)
E/flutter ( 5287): #5 _RawReceivePortImpl._handleMessage (dart:isolate/runtime/libisolate_patch.dart:171:12)
I/flutter ( 5287): Another exception was thrown: 'package:flutter/src/widgets/sliver.dart': Failed assertion: line 1008 pos 14: 'insertFirst || _childElements[index-1] != null': is not true.
I/chatty ( 5287): uid=10086(com.example.aurorav10) 1.ui identical 3 lines
I/flutter ( 5287): Another exception was thrown: 'package:flutter/src/widgets/sliver.dart': Failed assertion: line 1008 pos 14: 'insertFirst || _childElements[index-1] != null': is not true.
I/flutter ( 5287): Another exception was thrown: 'package:flutter/src/widgets/sliver.dart': Failed assertion: line 1053 pos 14: '_childElements.containsKey(index)': is not true.
I/chatty ( 5287): uid=10086(com.example.aurorav10) 1.ui identical 43 lines
I/flutter ( 5287): Another exception was thrown: 'package:flutter/src/widgets/sliver.dart': Failed assertion: line 1053 pos 14: '_childElements.containsKey(index)': is not true.
I/flutter ( 5287): Another exception was thrown: 'package:flutter/src/widgets/sliver.dart': Failed assertion: line 1008 pos 14: 'insertFirst || _childElements[index-1] != null': is not true.
I/chatty ( 5287): uid=10086(com.example.aurorav10) 1.ui identical 7 lines
I/flutter ( 5287): Another exception was thrown: 'package:flutter/src/widgets/sliver.dart': Failed assertion: line 1008 pos 14: 'insertFirst || _childElements[index-1] != null': is not true.
I/flutter ( 5287): Another exception was thrown: 'package:flutter/src/rendering/sliver_multi_box_adaptor.dart': Failed assertion: line 574 pos 16: 'indexOf(child) == index': is not true.
I/flutter ( 5287): Another exception was thrown: 'package:flutter/src/rendering/sliver_multi_box_adaptor.dart': Failed assertion: line 235 pos 16: 'indexOf(child) > index': is not true.
I/chatty ( 5287): uid=10086(com.example.aurorav10) 1.ui identical 1 line
I/flutter ( 5287): Another exception was thrown: 'package:flutter/src/rendering/sliver_multi_box_adaptor.dart': Failed assertion: line 235 pos 16: 'indexOf(child) > index': is not true.
I/flutter ( 5287): Another exception was thrown: 'package:flutter/src/widgets/framework.dart': Failed assertion: line 2270 pos 20: '_debugCurrentBuildTarget == context': is not true.
I/flutter ( 5287): Another exception was thrown: 'package:flutter/src/rendering/sliver_multi_box_adaptor.dart': Failed assertion: line 461 pos 12: 'child.hasSize': is not true.
I/flutter ( 5287): Another exception was thrown: 'package:flutter/src/rendering/sliver_multi_box_adaptor.dart': Failed assertion: line 574 pos 16: 'indexOf(child) == index': is not true.
I/chatty ( 5287): uid=10086(com.example.aurorav10) 1.ui identical 4 lines
I/flutter ( 5287): Another exception was thrown: 'package:flutter/src/rendering/sliver_multi_box_adaptor.dart': Failed assertion: line 574 pos 16: 'indexOf(child) == index': is not true.
I/flutter ( 5287): Another exception was thrown: 'package:flutter/src/widgets/sliver.dart': Failed assertion: line 1053 pos 14: '_childElements.containsKey(index)': is not true.
I/flutter ( 5287): Another exception was thrown: 'package:flutter/src/rendering/sliver_multi_box_adaptor.dart': Failed assertion: line 574 pos 16: 'indexOf(child) == index': is not true.
I/chatty ( 5287): uid=10086(com.example.aurorav10) 1.ui identical 6 lines
I/flutter ( 5287): Another exception was thrown: 'package:flutter/src/rendering/sliver_multi_box_adaptor.dart': Failed assertion: line 574 pos 16: 'indexOf(child) == index': is not true.
I/flutter ( 5287): Another exception was thrown: 'package:flutter/src/widgets/sliver.dart': Failed assertion: line 1053 pos 14: '_childElements.containsKey(index)': is not true.
I/chatty ( 5287): uid=10086(com.example.aurorav10) 1.ui identical 9 lines
I/flutter ( 5287): Another exception was thrown: 'package:flutter/src/widgets/sliver.dart': Failed assertion: line 1053 pos 14: '_childElements.containsKey(index)': is not true.
I/flutter ( 5287): Another exception was thrown: 'package:flutter/src/widgets/sliver.dart': Failed assertion: line 1053 pos 14: '_childElements.containsKey(index)': is not true.
I/chatty ( 5287): uid=10086(com.example.aurorav10) 1.ui identical 58 lines
I/flutter ( 5287): Another exception was thrown: 'package:flutter/src/widgets/sliver.dart': Failed assertion: line 1053 pos 14: '_childElements.containsKey(index)': is not true.
I/flutter ( 5287): Another exception was thrown: 'package:flutter/src/rendering/sliver_multi_box_adaptor.dart': Failed assertion: line 574 pos 16: 'indexOf(child) == index': is not true.
I/chatty ( 5287): uid=10086(com.example.aurorav10) 1.ui identical 6 lines
I/flutter ( 5287): Another exception was thrown: 'package:flutter/src/rendering/sliver_multi_box_adaptor.dart': Failed assertion: line 574 pos 16: 'indexOf(child) == index': is not true.
I/flutter ( 5287): Another exception was thrown: 'package:flutter/src/widgets/sliver.dart': Failed assertion: line 1053 pos 14: '_childElements.containsKey(index)': is not true.
谢谢你
解决方案
首先，请在发布问题时将您的代码精简到绝对必要的程度。那里有很多代码需要解析（特别是因为它不是全英文的）。至少，清理您的评论等...
但是手头的问题是您在 initState() 函数中创建了一个计时器，_RopSayacState但从不停止它。正如您在问题中包含的错误所解释的那样，这将导致问题，因为当小部件不再在视图中时，它会从小部件树中删除，因此调用setState它会导致错误。
要解决此问题，您只需在删除小部件时取消计时器。最简单的方法是覆盖_RopSayacState. 应该是这样的。
@override
void dispose() {
_everySecond.cancel();
super.dispose();
}
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