在 Flutter 中获取值 TextEditingController 时出错
Error Get Value TextEditingController In Flutter
我想用循环从textEditingController取值，listview没有滚动时出现的问题会报错，“RangeError (index): Invalid value: Not in inclusive range 0..23 : 24", 我有 40 条记录的随机数据，
当滚动到行尾时，应用程序将 运行 正确。我想要即使我不向下滚动数据仍然可以无错误地检索。
你可以运行我的示例代码，请帮助我谢谢。
import 'dart:math';
import 'package:flutter/material.dart';
class Karyawan {
int id;
String nama;
int jamKerja;
Karyawan({this.id, this.nama,});
Karyawan.fromJson(Map<String, dynamic> json) {
id = json['id'];
nama = json['nama_karyawan'];
jamKerja = json['jam_kerja'];
}
Map<String, dynamic> toJson() {
final Map<String, dynamic> data = new Map<String, dynamic>();
data['id'] = this.id;
data['nama_karyawan'] = this.nama;
data['jam_kerja'] = this.jamKerja;
return data;
}
}
List<Karyawan> _daftarKaryawan = List.generate(
40,
(index) => Karyawan(
id: Random().nextInt(100),
nama: 'test ${Random().nextInt(100)}',
),
);
class FormInputAbsenV3 extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("Entry Absen"),
),
body: FormEntry(listKaryawan:_daftarKaryawan)
);
}
}
class FormEntry extends StatefulWidget {
final List<Karyawan> listKaryawan;
const FormEntry({Key key, this.listKaryawan}) : super(key: key);
@override
_FormEntryState createState() => _FormEntryState();
}
class _FormEntryState extends State<FormEntry> {
List karyawan = [];
final _formKey = GlobalKey<FormState>();
List<TextEditingController> _brutos = new List();
List<TextEditingController> _nettos = new List();
void addlistAbsen() {
for (int i = 0; i < widget.listKaryawan.length; i++) {
karyawan.add({
"id": widget.listKaryawan[i].id,
"bruto": _brutos[i].text,
"netto": _nettos[i].text
});
}
print(karyawan);
}
@override
Widget build(BuildContext context) {
return Scaffold(
body: Container(
margin: EdgeInsets.all(5.0),
child: Form(
key: _formKey,
child: Container(
child: ListView.builder(
itemCount: widget.listKaryawan.length,
itemBuilder: (context,index) {
_brutos.add(new TextEditingController());
_nettos.add(new TextEditingController());
return Column(
children: [
FormWidget(
index: index,
nama: widget.listKaryawan[index].nama,
brucon: _brutos[index],
netcon: _nettos[index],
),
SizedBox(
height: 20.0,
),
],
);
},
),
),
),
),
floatingActionButton: FloatingActionButton.extended(
icon: Icon(Icons.save),
label: Text("Save"),
onPressed: () {
if (_formKey.currentState.validate()) {
addlistAbsen();
}
},
),
);
}
}
class FormWidget extends StatelessWidget {
final int index;
final String nama;
final brucon;
final netcon;
FormWidget({this.index, this.nama, this.brucon, this.netcon});
@override
Widget build(BuildContext context) {
return Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: [
Expanded(
child: Text("${index + 1}. ${nama}"),
),
Expanded(
child: TextFormField(
decoration: new InputDecoration(
labelText: "Bruto",
fillColor: Colors.white,
border: new OutlineInputBorder(
borderRadius: new BorderRadius.circular(25.0),
borderSide: new BorderSide(),
),
),
style: new TextStyle(
fontFamily: "Poppins",
),
controller: brucon,
),
),
SizedBox(
width: 20.0,
),
Expanded(
child: TextFormField(
decoration: new InputDecoration(
labelText: "Netto",
fillColor: Colors.white,
border: new OutlineInputBorder(
borderRadius: new BorderRadius.circular(25.0),
borderSide: new BorderSide(),
),
),
style: new TextStyle(
fontFamily: "Poppins",
),
controller: netcon,
))
],
);
}
}
您不能使用ListView.builder for this and you will have to use ListView。您不能使用 ListView.builder 构造函数，因为构建器仅针对那些实际可见的子级调用。请参阅 ListView.builder
的文档
ListView.builder constructor
Creates a scrollable, linear array of widgets that are created on
demand.
This constructor is appropriate for list views with a large (or
infinite) number of children because the builder is called only for
those children that are actually visible.
请看下面的代码：
import 'package:flutter/material.dart';
import 'dart:math';
final Color darkBlue = const Color.fromARGB(255, 18, 32, 47);
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
//theme: ThemeData.dark().copyWith(scaffoldBackgroundColor: darkBlue),
debugShowCheckedModeBanner: false,
home: Scaffold(
body: Center(
child: FormInputAbsenV3(),
),
),
);
}
}
class Karyawan {
int id;
String nama;
int jamKerja;
Karyawan({
this.id,
this.nama,
});
Karyawan.fromJson(Map<String, dynamic> json) {
id = json['id'];
nama = json['nama_karyawan'];
jamKerja = json['jam_kerja'];
}
Map<String, dynamic> toJson() {
final Map<String, dynamic> data = Map<String, dynamic>();
data['id'] = this.id;
data['nama_karyawan'] = this.nama;
data['jam_kerja'] = this.jamKerja;
return data;
}
}
List<Karyawan> _daftarKaryawan = List.generate(
40,
(index) => Karyawan(
id: Random().nextInt(100),
nama: 'test ${Random().nextInt(100)}',
),
);
class FormInputAbsenV3 extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("Entry Absen"),
),
body: FormEntry(listKaryawan: _daftarKaryawan));
}
}
class FormEntry extends StatefulWidget {
final List<Karyawan> listKaryawan;
const FormEntry({Key key, this.listKaryawan}) : super(key: key);
@override
_FormEntryState createState() => _FormEntryState();
}
class _FormEntryState extends State<FormEntry> {
List karyawan = [];
final _formKey = GlobalKey<FormState>();
List<TextEditingController> _brutos = [];
List<TextEditingController> _nettos = [];
@override
void initState() {
super.initState();
for (int i = 0; i < widget.listKaryawan.length; i++) {
_brutos.add(TextEditingController());
_nettos.add(TextEditingController());
}
}
void addlistAbsen() {
for (int i = 0; i < widget.listKaryawan.length; i++) {
karyawan.add({
"id": widget.listKaryawan[i].id,
"bruto": _brutos[i].text,
"netto": _nettos[i].text
});
}
print(karyawan);
}
@override
Widget build(BuildContext context) {
return Scaffold(
body: Container(
margin: EdgeInsets.all(5.0),
child: Form(
key: _formKey,
child: Container(
// child: ListView.builder(
// itemCount: widget.listKaryawan.length,
// itemBuilder: (context, index) {
// _brutos.add(new TextEditingController());
// _nettos.add(new TextEditingController());
// return Column(
// children: [
// FormWidget(
// index: index,
// nama: widget.listKaryawan[index].nama,
// brucon: _brutos[index],
// netcon: _nettos[index],
// ),
// SizedBox(
// height: 20.0,
// ),
// ],
// );
// },
// ),
child: ListView(
children: [
for (int index = 0; index < widget.listKaryawan.length; index++)
Column(
children: [
FormWidget(
index: index,
nama: widget.listKaryawan[index].nama,
brucon: _brutos[index],
netcon: _nettos[index],
),
SizedBox(
height: 20.0,
),
],
),
],
),
),
),
),
floatingActionButton: FloatingActionButton.extended(
icon: Icon(Icons.save),
label: Text("Save"),
onPressed: () {
if (_formKey.currentState.validate()) {
addlistAbsen();
}
},
),
);
}
}
class FormWidget extends StatelessWidget {
final int index;
final String nama;
final TextEditingController brucon;
final TextEditingController netcon;
const FormWidget({this.index, this.nama, this.brucon, this.netcon});
@override
Widget build(BuildContext context) {
return Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: [
Expanded(
child: Text("${index + 1}. ${nama}"),
),
Expanded(
child: TextFormField(
decoration: InputDecoration(
labelText: "Bruto",
fillColor: Colors.white,
border: OutlineInputBorder(
borderRadius: BorderRadius.circular(25.0),
borderSide: BorderSide(),
),
),
style: TextStyle(
fontFamily: "Poppins",
),
controller: brucon,
),
),
SizedBox(
width: 20.0,
),
Expanded(
child: TextFormField(
decoration: InputDecoration(
labelText: "Netto",
fillColor: Colors.white,
border: OutlineInputBorder(
borderRadius: BorderRadius.circular(25.0),
borderSide: BorderSide(),
),
),
style: TextStyle(
fontFamily: "Poppins",
),
controller: netcon,
))
],
);
}
}
请在 initState 期间初始化您的 TextEditingControllers。
@override
void initState() {
super.initState();
for (int i = 0; i < widget.listKaryawan.length; i++) {
_brutos.add(new TextEditingController());
_nettos.add(new TextEditingController());
}
}
然后，删除 itemBuilder 中的这些行...
_brutos.add(new TextEditingController());
_nettos.add(new TextEditingController());
注意：redisplayed/newly 显示列表项时将调用 itemBuilder。因此，您的 TextEditingControllers 列表 > 列表项。 （尝试滚动到最底部，然后向上滚动）
我想用循环从textEditingController取值，listview没有滚动时出现的问题会报错，“RangeError (index): Invalid value: Not in inclusive range 0..23 : 24", 我有 40 条记录的随机数据， 当滚动到行尾时，应用程序将 运行 正确。我想要即使我不向下滚动数据仍然可以无错误地检索。
你可以运行我的示例代码，请帮助我谢谢。
import 'dart:math';
import 'package:flutter/material.dart';
class Karyawan {
int id;
String nama;
int jamKerja;
Karyawan({this.id, this.nama,});
Karyawan.fromJson(Map<String, dynamic> json) {
id = json['id'];
nama = json['nama_karyawan'];
jamKerja = json['jam_kerja'];
}
Map<String, dynamic> toJson() {
final Map<String, dynamic> data = new Map<String, dynamic>();
data['id'] = this.id;
data['nama_karyawan'] = this.nama;
data['jam_kerja'] = this.jamKerja;
return data;
}
}
List<Karyawan> _daftarKaryawan = List.generate(
40,
(index) => Karyawan(
id: Random().nextInt(100),
nama: 'test ${Random().nextInt(100)}',
),
);
class FormInputAbsenV3 extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("Entry Absen"),
),
body: FormEntry(listKaryawan:_daftarKaryawan)
);
}
}
class FormEntry extends StatefulWidget {
final List<Karyawan> listKaryawan;
const FormEntry({Key key, this.listKaryawan}) : super(key: key);
@override
_FormEntryState createState() => _FormEntryState();
}
class _FormEntryState extends State<FormEntry> {
List karyawan = [];
final _formKey = GlobalKey<FormState>();
List<TextEditingController> _brutos = new List();
List<TextEditingController> _nettos = new List();
void addlistAbsen() {
for (int i = 0; i < widget.listKaryawan.length; i++) {
karyawan.add({
"id": widget.listKaryawan[i].id,
"bruto": _brutos[i].text,
"netto": _nettos[i].text
});
}
print(karyawan);
}
@override
Widget build(BuildContext context) {
return Scaffold(
body: Container(
margin: EdgeInsets.all(5.0),
child: Form(
key: _formKey,
child: Container(
child: ListView.builder(
itemCount: widget.listKaryawan.length,
itemBuilder: (context,index) {
_brutos.add(new TextEditingController());
_nettos.add(new TextEditingController());
return Column(
children: [
FormWidget(
index: index,
nama: widget.listKaryawan[index].nama,
brucon: _brutos[index],
netcon: _nettos[index],
),
SizedBox(
height: 20.0,
),
],
);
},
),
),
),
),
floatingActionButton: FloatingActionButton.extended(
icon: Icon(Icons.save),
label: Text("Save"),
onPressed: () {
if (_formKey.currentState.validate()) {
addlistAbsen();
}
},
),
);
}
}
class FormWidget extends StatelessWidget {
final int index;
final String nama;
final brucon;
final netcon;
FormWidget({this.index, this.nama, this.brucon, this.netcon});
@override
Widget build(BuildContext context) {
return Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: [
Expanded(
child: Text("${index + 1}. ${nama}"),
),
Expanded(
child: TextFormField(
decoration: new InputDecoration(
labelText: "Bruto",
fillColor: Colors.white,
border: new OutlineInputBorder(
borderRadius: new BorderRadius.circular(25.0),
borderSide: new BorderSide(),
),
),
style: new TextStyle(
fontFamily: "Poppins",
),
controller: brucon,
),
),
SizedBox(
width: 20.0,
),
Expanded(
child: TextFormField(
decoration: new InputDecoration(
labelText: "Netto",
fillColor: Colors.white,
border: new OutlineInputBorder(
borderRadius: new BorderRadius.circular(25.0),
borderSide: new BorderSide(),
),
),
style: new TextStyle(
fontFamily: "Poppins",
),
controller: netcon,
))
],
);
}
}
您不能使用ListView.builder for this and you will have to use ListView。您不能使用 ListView.builder 构造函数，因为构建器仅针对那些实际可见的子级调用。请参阅 ListView.builder
的文档ListView.builder constructor
Creates a scrollable, linear array of widgets that are created on demand.
This constructor is appropriate for list views with a large (or infinite) number of children because the builder is called only for those children that are actually visible.
请看下面的代码：
import 'package:flutter/material.dart';
import 'dart:math';
final Color darkBlue = const Color.fromARGB(255, 18, 32, 47);
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
//theme: ThemeData.dark().copyWith(scaffoldBackgroundColor: darkBlue),
debugShowCheckedModeBanner: false,
home: Scaffold(
body: Center(
child: FormInputAbsenV3(),
),
),
);
}
}
class Karyawan {
int id;
String nama;
int jamKerja;
Karyawan({
this.id,
this.nama,
});
Karyawan.fromJson(Map<String, dynamic> json) {
id = json['id'];
nama = json['nama_karyawan'];
jamKerja = json['jam_kerja'];
}
Map<String, dynamic> toJson() {
final Map<String, dynamic> data = Map<String, dynamic>();
data['id'] = this.id;
data['nama_karyawan'] = this.nama;
data['jam_kerja'] = this.jamKerja;
return data;
}
}
List<Karyawan> _daftarKaryawan = List.generate(
40,
(index) => Karyawan(
id: Random().nextInt(100),
nama: 'test ${Random().nextInt(100)}',
),
);
class FormInputAbsenV3 extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("Entry Absen"),
),
body: FormEntry(listKaryawan: _daftarKaryawan));
}
}
class FormEntry extends StatefulWidget {
final List<Karyawan> listKaryawan;
const FormEntry({Key key, this.listKaryawan}) : super(key: key);
@override
_FormEntryState createState() => _FormEntryState();
}
class _FormEntryState extends State<FormEntry> {
List karyawan = [];
final _formKey = GlobalKey<FormState>();
List<TextEditingController> _brutos = [];
List<TextEditingController> _nettos = [];
@override
void initState() {
super.initState();
for (int i = 0; i < widget.listKaryawan.length; i++) {
_brutos.add(TextEditingController());
_nettos.add(TextEditingController());
}
}
void addlistAbsen() {
for (int i = 0; i < widget.listKaryawan.length; i++) {
karyawan.add({
"id": widget.listKaryawan[i].id,
"bruto": _brutos[i].text,
"netto": _nettos[i].text
});
}
print(karyawan);
}
@override
Widget build(BuildContext context) {
return Scaffold(
body: Container(
margin: EdgeInsets.all(5.0),
child: Form(
key: _formKey,
child: Container(
// child: ListView.builder(
// itemCount: widget.listKaryawan.length,
// itemBuilder: (context, index) {
// _brutos.add(new TextEditingController());
// _nettos.add(new TextEditingController());
// return Column(
// children: [
// FormWidget(
// index: index,
// nama: widget.listKaryawan[index].nama,
// brucon: _brutos[index],
// netcon: _nettos[index],
// ),
// SizedBox(
// height: 20.0,
// ),
// ],
// );
// },
// ),
child: ListView(
children: [
for (int index = 0; index < widget.listKaryawan.length; index++)
Column(
children: [
FormWidget(
index: index,
nama: widget.listKaryawan[index].nama,
brucon: _brutos[index],
netcon: _nettos[index],
),
SizedBox(
height: 20.0,
),
],
),
],
),
),
),
),
floatingActionButton: FloatingActionButton.extended(
icon: Icon(Icons.save),
label: Text("Save"),
onPressed: () {
if (_formKey.currentState.validate()) {
addlistAbsen();
}
},
),
);
}
}
class FormWidget extends StatelessWidget {
final int index;
final String nama;
final TextEditingController brucon;
final TextEditingController netcon;
const FormWidget({this.index, this.nama, this.brucon, this.netcon});
@override
Widget build(BuildContext context) {
return Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: [
Expanded(
child: Text("${index + 1}. ${nama}"),
),
Expanded(
child: TextFormField(
decoration: InputDecoration(
labelText: "Bruto",
fillColor: Colors.white,
border: OutlineInputBorder(
borderRadius: BorderRadius.circular(25.0),
borderSide: BorderSide(),
),
),
style: TextStyle(
fontFamily: "Poppins",
),
controller: brucon,
),
),
SizedBox(
width: 20.0,
),
Expanded(
child: TextFormField(
decoration: InputDecoration(
labelText: "Netto",
fillColor: Colors.white,
border: OutlineInputBorder(
borderRadius: BorderRadius.circular(25.0),
borderSide: BorderSide(),
),
),
style: TextStyle(
fontFamily: "Poppins",
),
controller: netcon,
))
],
);
}
}
请在 initState 期间初始化您的 TextEditingControllers。
@override
void initState() {
super.initState();
for (int i = 0; i < widget.listKaryawan.length; i++) {
_brutos.add(new TextEditingController());
_nettos.add(new TextEditingController());
}
}
然后，删除 itemBuilder 中的这些行...
_brutos.add(new TextEditingController());
_nettos.add(new TextEditingController());
注意：redisplayed/newly 显示列表项时将调用 itemBuilder。因此，您的 TextEditingControllers 列表 > 列表项。 （尝试滚动到最底部，然后向上滚动）