Flutter 在从抽屉导航时引发生成错误期间调用setState（）或markNeedsBuild（）
我正在尝试建立一个应用程序，它有两个页面，即添加人页面和列表人页面。我的应用程序中有一个抽屉，如下面的代码所示。我正在尝试从抽屉导航到添加人员和列表人员页面，如下所示：Flutter 在从抽屉导航时引发生成错误期间调用setState（）或markNeedsBuild（）,flutter,Flutter,我正在尝试建立一个应用程序，它有两个页面，即添加人页面和列表人页面。我的应用程序中有一个抽屉，如下面的代码所示。我正在尝试从抽屉导航到添加人员和列表人员页面，如下所示： import 'package:flutter/material.dart'; import 'dart:async'; import 'package:track_aquintances/listPerson.dart'; class Formscreen extends StatefulWidget{ @overrid
import 'package:flutter/material.dart';
import 'dart:async';
import 'package:track_aquintances/listPerson.dart';
class Formscreen extends StatefulWidget{
@override
State<StatefulWidget> createState() {
return FormscreenState();
}
}
class FormscreenState extends State<Formscreen>{
DateTime _selectedDate = DateTime.now();
Widget _buildDateFIeld(){
return Container(
padding: const EdgeInsets.all(10),
child: Center(
child: Row(
children: <Widget>[
Expanded(
child: Column(
children: <Widget>[
Text(
"When did you meet this person?",
style: TextStyle(
fontSize: 16,
fontFamily: 'Montserrat'
),
),
],
)
)
],
),
),
);
}
Widget _buildNameField(){
return TextField(
decoration: InputDecoration(
icon: Icon(Icons.person),
labelText: 'Name',
labelStyle: TextStyle(
fontFamily: 'Montserrat',
fontWeight: FontWeight.bold,
color: Colors.grey
)
),
);
}
Widget _builPhoneField(){
return TextField(
keyboardType: TextInputType.number,
decoration: InputDecoration(
icon: Icon(Icons.phone),
labelText: 'Phone Number',
labelStyle: TextStyle(
fontFamily: 'Montserrat',
fontWeight: FontWeight.bold,
color: Colors.grey
)
),
);
}
Future<Null> _selectDate(BuildContext context) async {
final DateTime picked = await showDatePicker(
context: context,
initialDate: _selectedDate,
firstDate: DateTime(2015, 8),
lastDate: DateTime(2101));
if (picked != null && picked != _selectedDate)
setState(() {
_selectedDate = picked;
});
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Center(
child: Text(
"Track Acquintances",
style: TextStyle(
color: Colors.white,
fontFamily: 'Montserrat',
fontWeight: FontWeight.bold
),
),
),
),
drawer: Drawer(
child: ListView(
children: <Widget>[
DrawerHeader(
decoration: BoxDecoration(
gradient: LinearGradient(colors: <Color>[
Colors.teal, Colors.tealAccent
])
),
child: Container(
child: Column(
children: <Widget>[
Material(
elevation: 10,
borderRadius: BorderRadius.all(Radius.circular(50.0)),
child: Image.asset('images/corona.JPG', width: 100, height: 100),
)
],
),
),
),
CustomListTile('Add Person', Icons.add, addTapped()),
CustomListTile('View added People', Icons.people, listTapped(context)),
],
),
),
body: ListView(
children: <Widget>[
Container(
child: Stack(
children: <Widget>[
Container(
padding: EdgeInsets.fromLTRB(15.0, 40.0, 0.0, 0.0),
child: Text(
'Add Person',
textAlign: TextAlign.center,
style: TextStyle(
fontSize: 40.0,
color: Colors.teal,
fontWeight: FontWeight.bold,
fontFamily: 'Montserrat'
),
),
)
],
)
),
Container(
padding: EdgeInsets.only(top: 35.0, left: 20.0),
child: Column(
children: <Widget>[
_buildDateFIeld(),
RaisedButton(
onPressed: () => _selectDate(context),
child: Text(
'Select date',
style: TextStyle(
fontFamily: 'Montserrat'
),
)
),
_buildNameField(),
SizedBox(height: 10.0,),
_builPhoneField(),
SizedBox(height: 25.0,),
Container(
height: 40.0,
child: Material(
borderRadius: BorderRadius.circular(20.0),
shadowColor: Colors.greenAccent,
color: Colors.teal,
elevation: 7.0,
child: GestureDetector(
onTap: () {},
child: Center(
child: Text(
'Add',
style: TextStyle(
color: Colors.white,
fontFamily: 'Montserrat',
fontWeight: FontWeight.bold
),
),
),
),
),
)
],
),
)
],
)
);
}
}
addTapped(){
}
listTapped(context){
Navigator.of(context).pop();
Navigator.of(context).push(MaterialPageRoute(
builder: (context) => ListPerson()
));
}
class CustomListTile extends StatelessWidget{
final String _name;
final IconData _icon;
final Function onTap;
CustomListTile(this._name, this._icon, this.onTap);
@override
Widget build(BuildContext context) {
return Padding(
padding: EdgeInsets.fromLTRB(9, 0, 9, 0),
child: Container(
decoration: BoxDecoration(
border: Border(bottom: BorderSide(color: Colors.grey))
),
child: InkWell(
splashColor: Colors.teal,
onTap: () => onTap,
child: Container(
height: 50,
child: Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: <Widget>[
Row(
children: <Widget>[
Icon(_icon),
Padding(
padding: EdgeInsets.all(10),
child: Text(
_name,
style: TextStyle(
fontSize: 16,
fontFamily: 'Montserrat'
),
),
)
],
)
],
),
)
),
)
);
}
}
任何帮助都将不胜感激。提前谢谢。您可以复制下面的粘贴运行完整代码
listTapped（context）listTappedlistTappedCustomListTile('View added People', Icons.people, listTapped),
InWellonTaplistTapped(BuildContext context) async {
print("listTapped");
//Navigator.of(context).pop();
await Navigator.of(context)
.push(MaterialPageRoute(builder: (context) => ListPerson()));
Navigator.of(context).pop();
}
...
child: InkWell(
splashColor: Colors.teal,
onTap: () => onTap(context),
import 'package:flutter/material.dart';
import 'dart:async';
class Formscreen extends StatefulWidget {
@override
State<StatefulWidget> createState() {
return FormscreenState();
}
}
class FormscreenState extends State<Formscreen> {
DateTime _selectedDate = DateTime.now();
Widget _buildDateFIeld() {
return Container(
padding: const EdgeInsets.all(10),
child: Center(
child: Row(
children: <Widget>[
Expanded(
child: Column(
children: <Widget>[
Text(
"When did you meet this person?",
style: TextStyle(fontSize: 16, fontFamily: 'Montserrat'),
),
],
))
],
),
),
);
}
Widget _buildNameField() {
return TextField(
decoration: InputDecoration(
icon: Icon(Icons.person),
labelText: 'Name',
labelStyle: TextStyle(
fontFamily: 'Montserrat',
fontWeight: FontWeight.bold,
color: Colors.grey)),
);
}
Widget _builPhoneField() {
return TextField(
keyboardType: TextInputType.number,
decoration: InputDecoration(
icon: Icon(Icons.phone),
labelText: 'Phone Number',
labelStyle: TextStyle(
fontFamily: 'Montserrat',
fontWeight: FontWeight.bold,
color: Colors.grey)),
);
}
Future<Null> _selectDate(BuildContext context) async {
final DateTime picked = await showDatePicker(
context: context,
initialDate: _selectedDate,
firstDate: DateTime(2015, 8),
lastDate: DateTime(2101));
if (picked != null && picked != _selectedDate)
setState(() {
_selectedDate = picked;
});
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Center(
child: Text(
"Track Acquintances",
style: TextStyle(
color: Colors.white,
fontFamily: 'Montserrat',
fontWeight: FontWeight.bold),
),
),
),
drawer: Drawer(
child: ListView(
children: <Widget>[
DrawerHeader(
decoration: BoxDecoration(
gradient: LinearGradient(
colors: <Color>[Colors.teal, Colors.tealAccent])),
child: Container(
child: Column(
children: <Widget>[
Material(
elevation: 10,
borderRadius: BorderRadius.all(Radius.circular(50.0)),
child: Image.asset('images/corona.JPG',
width: 100, height: 100),
)
],
),
),
),
CustomListTile('Add Person', Icons.add, addTapped),
CustomListTile('View added People', Icons.people, listTapped),
],
),
),
body: ListView(
children: <Widget>[
Container(
child: Stack(
children: <Widget>[
Container(
padding: EdgeInsets.fromLTRB(15.0, 40.0, 0.0, 0.0),
child: Text(
'Add Person',
textAlign: TextAlign.center,
style: TextStyle(
fontSize: 40.0,
color: Colors.teal,
fontWeight: FontWeight.bold,
fontFamily: 'Montserrat'),
),
)
],
)),
Container(
padding: EdgeInsets.only(top: 35.0, left: 20.0),
child: Column(
children: <Widget>[
_buildDateFIeld(),
RaisedButton(
onPressed: () => _selectDate(context),
child: Text(
'Select date',
style: TextStyle(fontFamily: 'Montserrat'),
)),
_buildNameField(),
SizedBox(
height: 10.0,
),
_builPhoneField(),
SizedBox(
height: 25.0,
),
Container(
height: 40.0,
child: Material(
borderRadius: BorderRadius.circular(20.0),
shadowColor: Colors.greenAccent,
color: Colors.teal,
elevation: 7.0,
child: GestureDetector(
onTap: () {},
child: Center(
child: Text(
'Add',
style: TextStyle(
color: Colors.white,
fontFamily: 'Montserrat',
fontWeight: FontWeight.bold),
),
),
),
),
)
],
),
)
],
));
}
}
addTapped() {
print("addTapped");
}
listTapped(BuildContext context) async {
print("listTapped");
//Navigator.of(context).pop();
await Navigator.of(context)
.push(MaterialPageRoute(builder: (context) => ListPerson()));
Navigator.of(context).pop();
}
class CustomListTile extends StatelessWidget {
final String _name;
final IconData _icon;
final Function onTap;
CustomListTile(this._name, this._icon, this.onTap);
@override
Widget build(BuildContext context) {
return Padding(
padding: EdgeInsets.fromLTRB(9, 0, 9, 0),
child: Container(
decoration: BoxDecoration(
border: Border(bottom: BorderSide(color: Colors.grey))),
child: InkWell(
splashColor: Colors.teal,
onTap: () => onTap(context),
child: Container(
height: 50,
child: Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: <Widget>[
Row(
children: <Widget>[
Icon(_icon),
Padding(
padding: EdgeInsets.all(10),
child: Text(
_name,
style: TextStyle(
fontSize: 16, fontFamily: 'Montserrat'),
),
)
],
)
],
),
)),
));
}
}
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: Formscreen(),
);
}
}
class ListPerson extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("List Person"),
),
body: Text("ListPerson"));
}
}
导入“包装：颤振/材料.省道”；
导入“dart:async”；
类Formscreen扩展StatefulWidget{
@凌驾
状态createState（）{
返回FormscreenState（）；
}
}
类FormscreenState扩展了状态{
DateTime _selectedDate=DateTime.now（）；
小部件_buildDateFIeld（）{
返回容器(
填充：常量边集。全部（10），
儿童：中心(
孩子：排(
儿童：[
扩大(
子：列(
儿童：[
正文(
“你什么时候认识这个人的？”，
样式：TextStyle（fontSize:16，fontFamily:“蒙特塞拉特”），
),
],
))
],
),
),
);
}
小部件_buildNameField（）{
返回文本字段(
装饰：输入装饰(
图标：图标（Icons.person），
labelText:'名称'，
标签样式：文本样式(
fontFamily：“蒙特塞拉特”，
fontWeight:fontWeight.bold，
颜色：颜色。灰色），
);
}
小部件_builPhoneField（）{
返回文本字段(
键盘类型：TextInputType.number，
装饰：输入装饰(
图标：图标（Icons.phone），
labelText:'电话号码'，
标签样式：文本样式(
fontFamily：“蒙特塞拉特”，
fontWeight:fontWeight.bold，
颜色：颜色。灰色），
);
}
Future\u selectDate（BuildContext上下文）异步{
选择的最终日期时间=等待showDatePicker(
上下文：上下文，
初始日期：\您选择的日期，
firstDate:DateTime（2015年8月），
lastDate:DateTime（2101））；
如果（已拾取！=null&&picked！=\u selectedDate）
设置状态（）{
_selectedDate=已拾取；
});
}
@凌驾
小部件构建（构建上下文）{
返回脚手架(
appBar:appBar(
标题：中心(
子：文本(
“追踪获得”，
样式：TextStyle(
颜色：颜色，白色，
fontFamily：“蒙特塞拉特”，
fontWeight:fontWeight.bold），
),
),
),
抽屉(
子：ListView(
儿童：[
抽屉阅读器(
装饰：盒子装饰(
梯度：线性梯度(
颜色：[colors.teal，colors.tealacent]），
子：容器(
子：列(
儿童：[
材料(
标高：10，
borderRadius:borderRadius.all（半径.圆形（50.0）），
子项：Image.asset（'images/corona.JPG'，
宽度：100，高度：100），
)
],
),
),
),
CustomListTile（'Add Person'，Icons.Add，addTapped），
CustomListTile（'查看添加的人'，Icons.People，listTapped），
],
),
),
正文：ListView(
儿童：[
容器(
子：堆栈(
儿童：[
容器(
填充：来自LTRB（15.0,40.0,0.0,0.0）的边缘设置，
子：文本(
“添加人员”，
textAlign:textAlign.center，
样式：TextStyle(
字体大小：40.0，
颜色：Colors.teal，
fontWeight:fontWeight.bold，
fontFamily：“蒙特塞拉特”），
),
)
],
)),
容器(
填充：仅限边缘设置（顶部：35.0，左侧：20.0），
子：列(
儿童：[
_buildDateFIeld（），
升起的按钮(
按下时：（）=>\u选择日期（上下文），
子：文本(
“选择日期”，
样式：TextStyle（fontFamily:“蒙特塞拉特”），
)),
_buildNameField（），
大小盒子(
身高：10.0，
),
_builPhoneField（），
大小盒子(
身高：25.0，
),
容器(
身高：40.0，
儿童：材料(
边界半径：边界半径。圆形（20.0），
shadowColor:Colors.greenAccent，
颜色：Colors.teal，
标高：7.0，
儿童：手势检测器(
onTap:（）{}，
儿童：中心(
子：文本(
“添加”，
样式：TextStyle(
颜色：颜色，白色，
fontFamily：“蒙特塞拉特”，
fontWeight:fontWeight.bold），
),
),
),
),
)
],
import 'package:flutter/material.dart';
import 'dart:async';
class Formscreen extends StatefulWidget {
@override
State<StatefulWidget> createState() {
return FormscreenState();
}
}
class FormscreenState extends State<Formscreen> {
DateTime _selectedDate = DateTime.now();
Widget _buildDateFIeld() {
return Container(
padding: const EdgeInsets.all(10),
child: Center(
child: Row(
children: <Widget>[
Expanded(
child: Column(
children: <Widget>[
Text(
"When did you meet this person?",
style: TextStyle(fontSize: 16, fontFamily: 'Montserrat'),
),
],
))
],
),
),
);
}
Widget _buildNameField() {
return TextField(
decoration: InputDecoration(
icon: Icon(Icons.person),
labelText: 'Name',
labelStyle: TextStyle(
fontFamily: 'Montserrat',
fontWeight: FontWeight.bold,
color: Colors.grey)),
);
}
Widget _builPhoneField() {
return TextField(
keyboardType: TextInputType.number,
decoration: InputDecoration(
icon: Icon(Icons.phone),
labelText: 'Phone Number',
labelStyle: TextStyle(
fontFamily: 'Montserrat',
fontWeight: FontWeight.bold,
color: Colors.grey)),
);
}
Future<Null> _selectDate(BuildContext context) async {
final DateTime picked = await showDatePicker(
context: context,
initialDate: _selectedDate,
firstDate: DateTime(2015, 8),
lastDate: DateTime(2101));
if (picked != null && picked != _selectedDate)
setState(() {
_selectedDate = picked;
});
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Center(
child: Text(
"Track Acquintances",
style: TextStyle(
color: Colors.white,
fontFamily: 'Montserrat',
fontWeight: FontWeight.bold),
),
),
),
drawer: Drawer(
child: ListView(
children: <Widget>[
DrawerHeader(
decoration: BoxDecoration(
gradient: LinearGradient(
colors: <Color>[Colors.teal, Colors.tealAccent])),
child: Container(
child: Column(
children: <Widget>[
Material(
elevation: 10,
borderRadius: BorderRadius.all(Radius.circular(50.0)),
child: Image.asset('images/corona.JPG',
width: 100, height: 100),
)
],
),
),
),
CustomListTile('Add Person', Icons.add, addTapped),
CustomListTile('View added People', Icons.people, listTapped),
],
),
),
body: ListView(
children: <Widget>[
Container(
child: Stack(
children: <Widget>[
Container(
padding: EdgeInsets.fromLTRB(15.0, 40.0, 0.0, 0.0),
child: Text(
'Add Person',
textAlign: TextAlign.center,
style: TextStyle(
fontSize: 40.0,
color: Colors.teal,
fontWeight: FontWeight.bold,
fontFamily: 'Montserrat'),
),
)
],
)),
Container(
padding: EdgeInsets.only(top: 35.0, left: 20.0),
child: Column(
children: <Widget>[
_buildDateFIeld(),
RaisedButton(
onPressed: () => _selectDate(context),
child: Text(
'Select date',
style: TextStyle(fontFamily: 'Montserrat'),
)),
_buildNameField(),
SizedBox(
height: 10.0,
),
_builPhoneField(),
SizedBox(
height: 25.0,
),
Container(
height: 40.0,
child: Material(
borderRadius: BorderRadius.circular(20.0),
shadowColor: Colors.greenAccent,
color: Colors.teal,
elevation: 7.0,
child: GestureDetector(
onTap: () {},
child: Center(
child: Text(
'Add',
style: TextStyle(
color: Colors.white,
fontFamily: 'Montserrat',
fontWeight: FontWeight.bold),
),
),
),
),
)
],
),
)
],
));
}
}
addTapped() {
print("addTapped");
}
listTapped(BuildContext context) async {
print("listTapped");
//Navigator.of(context).pop();
await Navigator.of(context)
.push(MaterialPageRoute(builder: (context) => ListPerson()));
Navigator.of(context).pop();
}
class CustomListTile extends StatelessWidget {
final String _name;
final IconData _icon;
final Function onTap;
CustomListTile(this._name, this._icon, this.onTap);
@override
Widget build(BuildContext context) {
return Padding(
padding: EdgeInsets.fromLTRB(9, 0, 9, 0),
child: Container(
decoration: BoxDecoration(
border: Border(bottom: BorderSide(color: Colors.grey))),
child: InkWell(
splashColor: Colors.teal,
onTap: () => onTap(context),
child: Container(
height: 50,
child: Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: <Widget>[
Row(
children: <Widget>[
Icon(_icon),
Padding(
padding: EdgeInsets.all(10),
child: Text(
_name,
style: TextStyle(
fontSize: 16, fontFamily: 'Montserrat'),
),
)
],
)
],
),
)),
));
}
}
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: Formscreen(),
);
}
}
class ListPerson extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("List Person"),
),
body: Text("ListPerson"));
}
}