我有 5 个菜单BottomNavigationBar。当我从一个切换到另一个时，有时会收到一条错误消息，例如
E/flutter (13314): [ERROR:flutter/lib/ui/ui_dart_state.cc(157)] Unhandled Exception: setState() called after dispose(): _PromoProductState#a00c8(lifecycle state: defunct, not mounted)
E/flutter (13314): 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.
E/flutter (13314): 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 (13314): 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 (13314): #0 State.setState.<anonymous closure>
package:flutter/…/widgets/framework.dart:1112
E/flutter (13314): #1 State.setState
package:flutter/…/widgets/framework.dart:1147
E/flutter (13314): #2 _PromoProductState.initState.<anonymous closure>
package:tokopedia/widgets/promo_product.dart:16
E/flutter (13314): #3 _rootRun (dart:async/zone.dart:1122:38)
E/flutter (13314): #4 _CustomZone.run (dart:async/zone.dart:1023:19)
E/flutter (13314): #5 _CustomZone.runGuarded (dart:async/zone.dart:925:7)
E/flutter (13314): #6 _CustomZone.bindCallbackGuarded.<anonymous closure> (dart:async/zone.dart:965:23)
E/flutter (13314): #7 _rootRun (dart:async/zone.dart:1126:13)
E/flutter (13314): #8 _CustomZone.run (dart:async/zone.dart:1023:19)
E/flutter (13314): #9 _CustomZone.bindCallback.<anonymous closure> (dart:async/zone.dart:949:23)
E/flutter (13314): #10 Timer._createTimer.<anonymous closure> (dart:async-patch/timer_patch.dart:23:15)
E/flutter (13314): #11 _Timer._runTimers (dart:isolate-patch/timer_impl.dart:384:19)
E/flutter (13314): #12 _Timer._handleMessage (dart:isolate-patch/timer_impl.dart:418:5)
E/flutter (13314): #13 _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:174:12)
只有当我从另一个菜单（快速）移动到home menu包含静态数据的菜单（现在不调用 api）时才会发生这种情况。
我想也许这段代码是问题所在
@override
void initState() {
Provider.of<LoadingState>(context, listen: false).setLoading = 0;
Timer(Duration(seconds: 1), () {
setState(() {
time = time.add(Duration(seconds: -1));
});
});
super.initState();
listBottomWidget.add(HomeTab());
listBottomWidget.add(FeedTab());
listBottomWidget.add(InboxTab());
listBottomWidget.add(CartTab());
listBottomWidget.add(AccountTab());
}
但我不确定
错误消息仅在我切换到HomeTab().
这是我的家.dart
import 'dart:async';
import 'package:flutter/material.dart';
import 'package:badges/badges.dart';
import 'package:provider/provider.dart';
import 'package:tokopedia/providers/loading_state.dart';
import 'package:tokopedia/view/tabs/tab_account.dart';
import 'package:tokopedia/view/tabs/tab_cart.dart';
import 'package:tokopedia/view/tabs/tab_feed.dart';
import 'package:tokopedia/view/tabs/tab_home.dart';
import 'package:tokopedia/view/tabs/tab_inbox.dart';
class HomePage extends StatefulWidget {
@override
State createState() => HomePageState();
}
class HomePageState extends State<HomePage> {
DateTime time = DateTime.now();
int selectedPosition = 0;
List<Widget> listBottomWidget = new List();
@override
void initState() {
Provider.of<LoadingState>(context, listen: false).setLoading = 0;
Timer(Duration(seconds: 1), () {
setState(() {
time = time.add(Duration(seconds: -1));
});
});
super.initState();
listBottomWidget.add(HomeTab());
listBottomWidget.add(FeedTab());
listBottomWidget.add(InboxTab());
listBottomWidget.add(CartTab());
listBottomWidget.add(AccountTab());
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
backgroundColor: Colors.white,
title: Row(
children: <Widget>[
Container(
padding: EdgeInsets.only(right: 12.0),
child: Image.asset(
"assets/images/qrcode.png",
width: 30,
height: 30,
),
),
Expanded(
child: Container(
padding: EdgeInsets.only(right: 8.0),
decoration: BoxDecoration(
color: Colors.grey[100],
borderRadius: BorderRadius.all(
Radius.circular(5.0),
),
),
child: TextField(
decoration: const InputDecoration(
prefixIcon: Icon(
Icons.search,
color: Colors.grey,
),
border: InputBorder.none,
hintText: 'What you need?',
),
style: TextStyle(
fontSize: 16,
),
),
),
),
],
),
actions: <Widget>[
BadgeIconButton(
itemCount: 0,
icon: Icon(
Icons.favorite,
size: 28.0,
color: Colors.grey[400],
),
badgeColor: Colors.red,
badgeTextColor: Colors.white,
hideZeroCount: true,
onPressed: () {},
),
BadgeIconButton(
itemCount: 4,
icon: Icon(
Icons.notifications,
size: 28.0,
color: Colors.grey[400],
),
badgeColor: Colors.red,
badgeTextColor: Colors.white,
hideZeroCount: true,
onPressed: () {},
),
],
),
body: Builder(
builder: (context) {
return listBottomWidget[selectedPosition];
},
),
bottomNavigationBar: BottomNavigationBar(
type: BottomNavigationBarType.fixed,
currentIndex: selectedPosition, // this will be set when a tab is tapped
items: [
BottomNavigationBarItem(
icon: Icon(Icons.home),
title: Text('Home'),
),
BottomNavigationBarItem(
icon: Icon(Icons.book),
title: Text('Feed'),
),
BottomNavigationBarItem(
icon: Icon(Icons.mail),
title: Text('Inbox'),
),
BottomNavigationBarItem(
icon: Icon(Icons.shopping_cart),
title: Text('Cart'),
),
BottomNavigationBarItem(
icon: Icon(Icons.people),
title: Text('Account'),
),
],
onTap: (position) {
setState(() {
selectedPosition = position;
});
},
),
);
}
}
我错过了什么吗？
谢谢
已编辑
我的家标签
import 'package:flutter/material.dart';
import 'package:tokopedia/widgets/banner_belanja_untung.dart';
import 'package:tokopedia/widgets/banner_beli_kebutuhan.dart';
import 'package:tokopedia/widgets/banner_promo_special.dart';
import 'package:tokopedia/widgets/image_slider.dart';
import 'package:tokopedia/widgets/kategori_pilihan.dart';
import 'package:tokopedia/widgets/menu_item.dart';
import 'package:tokopedia/widgets/most_trending_product.dart';
import 'package:tokopedia/widgets/promo_product.dart';
class HomeTab extends StatefulWidget {
@override
_HomeTabState createState() => _HomeTabState();
}
class _HomeTabState extends State<HomeTab> {
@override
Widget build(BuildContext context) {
var greyArea = Container(
height: 10.0,
color: Colors.grey[200],
);
return SingleChildScrollView(
child: Column(
children: <Widget>[
ImageSliderWidget(),
MenuItemWidget(),
greyArea,
PromoProduct(),
greyArea,
BannerPromoSpecial(),
KategoriPilihan(),
greyArea,
BannerBelanjaUntung(),
greyArea,
MostTrendingProduct(),
greyArea,
BannerBeliKebutuhan(),
greyArea,
KategoriPilihan(),
],
),
);
}
}
在我的PromoProduct小部件内
import 'dart:async';
import 'package:flutter/material.dart';
class PromoProduct extends StatefulWidget {
@override
_PromoProductState createState() => _PromoProductState();
}
class _PromoProductState extends State<PromoProduct> {
DateTime time = DateTime.now();
@override
void initState() {
Timer(Duration(seconds: 1), () {
setState(() {
time = time.add(Duration(seconds: -1));
});
});
super.initState();
}
@override
Widget build(BuildContext context) {
var promoProductItems = [
{
"image": "assets/images/product/tas.jpg",
"real_price": "Rp 249.000",
"discount_price": "Rp 87.150",
"discount_percent": "65",
},
{
"image": "assets/images/product/qtela.jpg",
"real_price": "Rp 25.000",
"discount_price": "Rp 20.000",
"discount_percent": "20",
},
{
"image": "assets/images/product/tropicana_slim.jpg",
"real_price": "Rp 83.500",
"discount_price": "Rp 58.500",
"discount_percent": "30",
},
{
"image": "assets/images/product/pipo_frixion.jpg",
"real_price": "Rp 27.000",
"discount_price": "Rp 16.200",
"discount_percent": "40",
},
{
"image": "assets/images/product/bioderma_sebium.jpg",
"real_price": "Rp 252.625",
"discount_price": "Rp 155.000",
"discount_percent": "39",
},
{
"image": "assets/images/product/maxim_new_prestige.jpg",
"real_price": "Rp 612.000",
"discount_price": "Rp 263.000",
"discount_percent": "57",
},
];
return Column(
children: <Widget>[
Container(
padding: EdgeInsets.all(12.0),
child: Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: <Widget>[
Container(
child: Row(
children: <Widget>[
Text("Flash Sale ",
style: TextStyle(
fontSize: 16.0,
fontWeight: FontWeight.bold,
)),
Container(
padding: EdgeInsets.all(4.0),
decoration: BoxDecoration(
color: Color(0xffff3e2f),
borderRadius: BorderRadius.all(Radius.circular(6.0)),
),
child: Text(
time.hour.toString().padLeft(2, "0"),
style: TextStyle(
color: Colors.white,
),
),
),
Text(
" : ",
style: TextStyle(
color: Color(0xffff3e2f),
),
),
Container(
padding: EdgeInsets.all(4.0),
decoration: BoxDecoration(
color: Color(0xffff3e2f),
borderRadius: BorderRadius.all(Radius.circular(6.0)),
),
child: Text(
time.minute.toString().padLeft(2, "0"),
style: TextStyle(
color: Colors.white,
),
),
),
Text(
" : ",
style: TextStyle(
color: Color(0xffff3e2f),
),
),
Container(
padding: EdgeInsets.all(4.0),
decoration: BoxDecoration(
color: Color(0xffff3e2f),
borderRadius: BorderRadius.all(Radius.circular(6.0)),
),
child: Text(
time.second.toString().padLeft(2, "0"),
style: TextStyle(
color: Colors.white,
),
),
),
],
),
),
Text("Lihat Semuanya",
style: TextStyle(
color: Colors.green,
)),
],
),
),
Container(
width: MediaQuery.of(context).size.width,
height: 280.0,
child: IgnorePointer(
child: GridView.count(
crossAxisCount: 3,
children: List.generate(
promoProductItems.length,
(index) {
return Column(
children: <Widget>[
Stack(
children: <Widget>[
Container(
height: 85.0,
child: Image.asset(
promoProductItems[index]["image"],
),
),
Positioned(
top: 0,
right: 0,
child: Container(
padding: EdgeInsets.all(4.0),
child: Text(
"${promoProductItems[index]["discount_percent"]} OFF",
style: TextStyle(
color: Colors.red[900],
fontSize: 10.0,
fontWeight: FontWeight.bold,
),
),
decoration: BoxDecoration(
color: Colors.red[100],
border: Border.all(
color: Colors.red,
width: 2.0,
),
borderRadius: BorderRadius.all(
Radius.circular(12.0),
),
),
),
),
],
),
Text(
promoProductItems[index]["real_price"],
style: TextStyle(
decoration: TextDecoration.lineThrough,
),
),
Text(
promoProductItems[index]["discount_price"],
style: TextStyle(
fontWeight: FontWeight.bold,
color: Colors.orange[900],
),
),
],
);
},
),
),
),
),
],
);
}
}
这不是一个完全正确的方法，但有时您需要使用它。喜欢你的问题。定义一个 bool 并在小部件处理时更改它。setState没有它就不要使用任何东西。例如;
DateTime time = DateTime.now();
bool _disposed = false;
@override
void initState() {
Timer(Duration(seconds: 1), () {
if (!_disposed)
setState(() {
time = time.add(Duration(seconds: -1));
});
});
super.initState();
}
@override
void dispose() {
_disposed = true;
super.dispose();
}
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