Well it's probably a very simple question but I'm starting and I'm not able to find too much documentation about flutter...
import 'package:flutter/material.dart';
class AutoChangeField extends StatefulWidget {
#override
_AutoChangeFieldState createState() => _AutoChangeFieldState();
}
class _AutoChangeFieldState extends State<AutoChangeField> {
Color _color = Colors.black;
String _newValue = 'write something';
#override
Widget build(BuildContext context) {
return TextFormField(
initialValue: _newValue,
cursorColor: _color,
onChanged: (val){
setState(() {
_newValue = "It changed!";
_color = Colors.red;
});
},
);
}
}
Just the cursorColor swaps to red properly when you write something at the TextFormField, but the value of it does not. Value keeps being "write something + (what u writed)" instead of "It changed!". :(
Thanks you so much.
You should use a TextEditingController and set the initialValue of the TextEditingController to "Write something"
Like this
class AutoChangeField extends StatefulWidget {
#override
_AutoChangeFieldState createState() => _AutoChangeFieldState();
}
class _AutoChangeFieldState extends State<AutoChangeField> {
Color _color = Colors.black;
TextEditingController controller = TextEditingController(text: "Write something");
#override
Widget build(BuildContext context) {
return TextFormField(
controller: controller,
cursorColor: _color,
onChanged: (val){
print(val);
controller.text = "It changed!";
setState(() {
_color = Colors.red;
});
},
);
}
}
NOTE: You cannot use the controller and initialValue at the same time.
You need to use 'controller' proeprty.
Define a controller like below :
TextEditingController myController = new TextEditingController();
Assign it to the TextFormField as :
TextFormField(
controller: myController,
Now, assign a new value as :
myController.text = "its changed";
Related
I created a widget for a textfield that accepts password and I made use of stateful widget. Now I want to get the value of what is written in the text field in two different files but I can't make the texteditingcontroller requiredenter image description here
Login Page should be something like this:
declare the controller in the login page then you can pass the controller to other Widget including Passwordfield, the Login page now is the owner of the controller it initialize it and dispose it.
class LoginPage extends StatefulWidget {
#override
_LoginPageState createState() => _LoginPageState();
}
class _LoginPageState extends State<LoginPage> {
late TextEditingController _passwordController;
#override
void initState() {
_passwordController = TextEditingController();
}
#override
void dispose() {
_passwordController.dispose();
}
Widget build(BuildContext context) {
return Column(
children: <Widget>[
// Emailfield(),
Passwordfield(
controller: _passwordController,
),
],
);
}
}
in the Passwordfield edit the constructor to use the controller in this Widget:
class Passwordfield extends StatefulWidget {
final TextEditingController controller;
Passwordfield({Key? key, required this.controller,}) : super(key: key);
#override
_PasswordfieldState createState() => _PasswordfieldState();
}
class _PasswordfieldState extends State<Passwordfield> {
ValueChanged<String> onChanged = (value) {};
String hintText = "password";
bool hidepassword = true;
Widget build(BuildContext context) {
return TextField(
controller: widget.controller,
onChanged: onChanged,
obscureText: hidepassword,
// ...
);
}
}
You can make it like this:
First you have to create controller :
var _controller = TextEditingController();
Second add this controller to your textfield
TextField(
autofocus: true,
controller: _controller, // add controller here
decoration: InputDecoration(
hintText: 'Test',
focusColor: Colors.white,
),
),
and finally in your button check if controller is empty or not
CustomButton(
onTap: () async {
if (_controller.text.trim().isEmpty) {
showCustomSnackBar(
'Password field is empty',
context);
}
}
)
just it
I found a similar behaviour on Safari:
The problem statement is that on tap of normal text, the text field should be editable and we can able to edit the text.
Have an example
In this scenario, we can see how on tap of initial text the editable text field is getting displayed and we can able to edit the text.
So let’s start with the process:
First, we have to initialize the variables.
bool _isEditingText = false;
TextEditingController _editingController;
String initialText = "Initial Text";
_isEditingText is the boolean variable and we have to set it false because we have to make it true when the user is tap on text.
TextEditingController -whenever a user modifies a text field with an associated TextEditingController, the text field edits and the controller notifies the listener. Listeners can then read the text and selection properties that the user has typed and updated. Basically the text editing controller is used to get the updated value from the text field.
initialText -Initial value, set to the text.
When we use any type of controller then we have to initialize and dispose of the controller.
So first initialize the controller in init state.
#override
void initState() {
super.initState();
_editingController = TextEditingController(text: initialText);
}
#override
void dispose() {
_editingController.dispose();
super.dispose();
}
‘dispose()’ is called when the State object is removed, which is permanent.
This method is used to unsubscribe and cancel all animations, streams, etc.
The framework calls this method when this state object will never build again.
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("'Editable Text"),
),
body: Center(
child: _editTitleTextField(),
),
);
}
In build widget, I am simply displaying a widget _editTitleTextField().
Widget _editTitleTextField() {
if (_isEditingText)
return Center(
child: TextField(
onSubmitted: (newValue){
setState(() {
initialText = newValue;
_isEditingText =false;
});
},
autofocus: true,
controller: _editingController,
),
);
return InkWell(
onTap: () {
setState(() {
_isEditingText = true;
});
},
child: Text(
initialText,
style: TextStyle(
color: Colors.black,
fontSize: 18.0,
),
);
}
so what exactly the _editTitleTextField() widget does is, if the value of _isEditingText is false then simply show the text and on tap of text set the value of _isEditingText to true.
When _isEditingText is true then _editTitleTextField return text field. Textfield has parameter onSubmitted, so in onSubmitted method new value is assigned to initialText which is the updated value getting from _editingController.
Tada! This way we make the text editable and update the value of the text!
This can be done by having a StatefulWidget that keeps track of the state, by using a boolean for example. Let's say this bool is named editing. When editing == false you display a Text widget with the text to display, wrapped within a handler for the tap, such as a GestureDetector. When the user taps, the state is changed to editing = true. In this state you'll display a TextField with this value. You can use a TextEditingController within in this StatefulWidget and update its value there. This would allow you to up have all text selected when the user taps and changes to the editing state
I believe this is the correct answer:
class InlineEditableText extends StatefulWidget {
const InlineEditableText({
Key? key,
required this.text,
required this.style,
}) : super(key: key);
final String text;
final TextStyle style;
#override
State<InlineEditableText> createState() => _InlineEditableTextState();
}
class _InlineEditableTextState extends State<InlineEditableText> {
var _isEditing = false;
final _focusNode = FocusNode();
late String _text = widget.text;
late final TextStyle _style = widget.style;
late TextEditingController _controller;
#override
void initState() {
_controller = TextEditingController(text: _text);
_focusNode.addListener(() {
if (!_focusNode.hasFocus) {
setState(() => _isEditing = false);
} else {
_controller.selection = TextSelection(
baseOffset: 0,
extentOffset: _controller.value.text.runes.length,
);
}
});
super.initState();
}
#override
void dispose() {
_controller.dispose();
_focusNode.dispose();
super.dispose();
}
#override
Widget build(BuildContext context) {
return GestureDetector(
onDoubleTap: () => setState(() {
_isEditing = !_isEditing;
_focusNode.requestFocus();
}),
child: TextField(
maxLines: 1,
style: _style,
focusNode: _focusNode,
controller: _controller,
onSubmitted: (changed) {
setState(() {
_text = changed;
_isEditing = false;
});
},
showCursor: _isEditing,
cursorColor: Colors.black,
enableInteractiveSelection: _isEditing,
decoration: InputDecoration(
isDense: true,
contentPadding: const EdgeInsets.symmetric(
horizontal: 0,
vertical: 4.4,
),
border: _isEditing
? const OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(0)),
)
: InputBorder.none,
),
),
);
}
}
I want to achieve this.
While a text form field is inactive, its background, fill color will be grey. But when I am typing or it is in active mode, its background color will be white.
How to achieve this behavior?
try this:
class CustomTextFiled extends StatefulWidget {
const CustomTextFiled({
Key? key,
this.focusNode,
required this.fillColor,
required this.focusColor,
// add whaterver properties that your textfield needs. like controller and ..
}) : super(key: key);
final FocusNode? focusNode;
final Color focusColor;
final Color fillColor;
#override
_CustomTextFiledState createState() => _CustomTextFiledState();
}
class _CustomTextFiledState extends State<CustomTextFiled> {
late FocusNode focusNode;
#override
void initState() {
focusNode = widget.focusNode ?? FocusNode();
focusNode.addListener(() {
setState(() {});
});
super.initState();
}
#override
Widget build(BuildContext context) {
return TextField(
focusNode: focusNode,
decoration: InputDecoration(
filled: true,
fillColor: focusNode.hasFocus ? widget.focusColor : widget.fillColor,
),
);
}
}
You can use FocusNode with listener.
late final FocusNode focusNode = FocusNode()
..addListener(() {
setState(() {});
});
....
TextField(
focusNode: focusNode,
decoration: InputDecoration(
fillColor: focusNode.hasFocus ? Colors.white : null,
filled: focusNode.hasFocus ? true : null,
),
)
After going through some tests, I have finalized the correct answer. The above answer is good. The first one has a problem. Focus Node variable must be inside the state class so that it can preserve its state.
class _GlobalTextFormFieldState extends State<GlobalTextFormField> {
late FocusNode focusNode;
#override
void initState() {
focusNode = FocusNode();
focusNode.addListener(() {
setState(() {});
});
super.initState();
}
#override
Widget build(BuildContext context) {
return TextFormField(
focusNode: focusNode,
);
}
}
I am creating an weather app in which I am providing a location string to a TextField and fetch the text inside in it. I know I can do it if I use TextField widget every time, but I want to use code reusability and that's why I have created a different Widget called TextFieldWidget in which I am providing a hint variable, which returns the Text inside it. I don't know how to do return the text. This is my code.
import 'package:flutter/material.dart';
class TextFieldWidget extends StatefulWidget {
final String _hint;
TextFieldWidget(this._hint);
#override
_TextFieldWidgetState createState() => _TextFieldWidgetState();
}
class _TextFieldWidgetState extends State<TextFieldWidget> {
TextEditingController _textEditingController;
InputDecoration _inputdecoration;
#override
void initState() {
super.initState();
_textEditingController = TextEditingController();
_inputdecoration = InputDecoration(hintText: widget._hint,floatingLabelBehavior: FloatingLabelBehavior.always);
}
#override
Widget build(BuildContext context) {
return TextField(
autocorrect: true,
controller: _textEditingController,
keyboardType: TextInputType.text,
enableSuggestions: true,
decoration: _inputdecoration,
onSubmitted: (value){
// somehow return data
// I want to access this part..
},
);
}
}
1. You have to create one method inside calling class
void _setTextValue(String value) {
// Submitted text should appear here from value
}
TextFieldWidget(_setTextValue)
2. Use this inside TextFormField then
final Function _setValue;
TextFieldWidget(this._setValue);
3. Inside onSubmitted Call
widget._setValue(value);
Finally, you will get value inside calling class
Edited:
We can add callbacks in calling widgets itself with named parameters which is correct way of doing this
Example:
class _TextFieldWidgetState extends State<TextFieldWidget> {
TextEditingController _textEditingController;
InputDecoration _inputdecoration;
#override
void initState() {
super.initState();
_textEditingController = TextEditingController();
_inputdecoration = InputDecoration(hintText: 'UserName',floatingLabelBehavior: FloatingLabelBehavior.always);
}
#override
Widget build(BuildContext context) {
return TextField(
autocorrect: true,
controller: _textEditingController,
keyboardType: TextInputType.text,
enableSuggestions: true,
decoration: _inputdecoration,
onSubmitted: (value){
widget.getUserName(value);
// somehow return data
// I want to access this part..
},
);
}
}
Call above code like
TextFieldWidget(getUserName: (value) {
// Get the username here
print(value);
}),
Note: We can add as many as named parameter like this
Given a stateful widget, is somehow possible to call a method defined in the State class (the one which extends State<NameOfTheWidget>). Actually, I just want to rebuild the _State class, like calling setState() but from outside of the class. I know how to it from children to parents but not viceversa.
class Foo extends StatefulWidget{
State createState() => new _State();
//...bar() ??
}
class _State extends State<Foo>{
#override
Widget build(BuildContext context) {...}
void bar(){...}
}
EDIT: some real code
First, we hace the equivalent to the inner widget; it's a a customized text field. The point is that I want enable and disable it according to the boolean _activo variable.
import 'package:flutter/material.dart';
import 'package:bukit/widgets/ensure.dart';
class EntradaDatos extends StatelessWidget{
final String _titulo;
final String _hint;
TextEditingController _tec;
FocusNode _fn = new FocusNode();
final String Function(String s) _validador;
final TextInputType _tit;
bool _activo;
/*
* CONSTRUCTOR
*/
EntradaDatos(this._titulo, this._hint, this._validador, this._tit, this._activo){
_tec = new TextEditingController();
}
#override
Widget build(BuildContext context){
print('Construyendo');
return new EnsureVisibleWhenFocused(
focusNode: _fn,
child: new TextFormField(
enabled: _activo,
keyboardType: _tit,
validator: _validador,
autovalidate: true,
focusNode: _fn,
controller: _tec,
decoration: InputDecoration(
labelText: _titulo,
hintText: _hint
),
)
);
}
String getContenido(){
return _tec.text;
}
}
Then I have a concrete implementation of the previous text field, which just extends it:
import 'package:flutter/material.dart';
import 'package:bukit/widgets/entrada_datos.dart';
class EntradaMail extends EntradaDatos{
static String _hint = "nombre#dominio.es";
static String _validador(String s){
if(s.isEmpty){
return 'El campo es obligatorio';
}else{
if(!s.contains('#') || !s.contains('.') || s.contains(' ')){
return 'Introduce una dirección válida';
}else{
String nombre = s.substring(0, s.indexOf('#'));
String servidor = s.substring(s.indexOf('#')+1, s.lastIndexOf('.'));
String dominio = s.substring(s.lastIndexOf('.')+1);
if(nombre.length < 2 || servidor.length < 2 || dominio.length < 2){
return 'Introduce una dirección válida';
}
}
}
}
EntradaMail(String titulo, bool activo) : super(titulo, _hint, _validador, TextInputType.emailAddress, activo);
}
Finally, the equivalent of my outter widget. It's just a checkbox followed by the prevoius EntradaEmail widget. As far as I know, once the checkbox is pressed and the onChange call is made, the setState call should rebuild everything, but I've contrasted with debug messaged that the build method of the first inner widget is never called. My point is enabling and disabling the text field according to the checkbox.
class CampoEnvio extends StatefulWidget{
EntradaMail _mail;
EntradaMovil _movil;
String _tituloMail;
String _tituloMovil;
bool _usaMail = false;
bool _usaMovil = false;
CampoEnvio(this._tituloMail, this._tituloMovil){
_mail = new EntradaMail(_tituloMail, _usaMail);
_movil = new EntradaMovil(_tituloMovil, _usaMovil);
}
State createState() => _State(_mail, _movil, _usaMail, _usaMovil, _tituloMail, _tituloMovil);
}
class _State extends State<CampoEnvio>{
bool _usaMail;
bool _usaMovil;
String _tituloMail;
String _tituloMovil;
EntradaMail _mail;
EntradaMovil _movil;
_State(this._mail, this._movil, this._usaMail, this._usaMovil, this._tituloMail, this._tituloMovil);
#override
Widget build(BuildContext context){
return new Column(
children: <Widget>[
new ListTile(
leading: new SizedBox(
width: 70.0,
child: new Row(
children: <Widget>[
new Checkbox(
value: _usaMail,
activeColor: Colors.black,
onChanged: (value) {
setState(() {
_usaMail = value;
});
},
),
],
),
),
title: _mail,
),
//...
new Divider()
],
);
}
}
Yes, in theory it is possible using a GlobalKey, but not recommended!
class OuterWidget extends StatefulWidget {
#override
State<StatefulWidget> createState() => OuterWidgetState();
}
class OuterWidgetState extends State<OuterWidget> {
final _innerKey = GlobalKey<InnerWidgetState>();
#override
Widget build(BuildContext context) {
return Column(
children: <Widget>[
InnerWidget(key: _innerKey),
RaisedButton(
child: Text('call foo'),
onPressed: () {
_innerKey.currentState.foo();
},
)
],
);
}
}
class InnerWidget extends StatefulWidget {
InnerWidget({Key key}) : super(key: key);
#override
State<StatefulWidget> createState() => InnerWidgetState();
}
class InnerWidgetState extends State<InnerWidget> {
String _value = 'not foo';
#override
Widget build(BuildContext context) {
return Text(_value);
}
void foo() {
setState(() {
_value = 'totally foo';
});
}
}
Better approach: Instead, what it would be a good idea to pull the state up:
class OuterWidget extends StatefulWidget {
#override
State<StatefulWidget> createState() => OuterWidgetState();
}
class OuterWidgetState extends State<OuterWidget> {
String _innerValue;
#override
Widget build(BuildContext context) {
return Column(
children: <Widget>[
InnerWidget(value: _innerValue),
RaisedButton(
child: Text('call foo'),
onPressed: () {
setState(() {
_innerValue = 'totally foo';
});
},
)
],
);
}
}
class InnerWidget extends StatefulWidget {
InnerWidget({Key key, this.value}) : super(key: key);
final String value;
#override
State<StatefulWidget> createState() => InnerWidgetState();
}
class InnerWidgetState extends State<InnerWidget> {
#override
Widget build(BuildContext context) {
return Text(widget.value);
}
}
If you can, make the inner widget stateless:
class InnerWidget extends StatelessWidget {
InnerWidget({Key key, this.value}) : super(key: key);
final String value;
#override
Widget build(BuildContext context) {
return Text(value);
}
}
If your child is interactive (taps, checkbox...), you can define callbacks with VoidCallback or ValueChanged<T> (or your own typedef) to process the events in the parent widget.
Ok, now that you added the sample code, I will try to explain why your widget does not work, and I will try to explain what other improvements can be made.
First of all, you can improve the readability of your code by using named constructors for all of your widgets, like in my other answers (You can auto-generate them with Android Studio: Define some final fields, then press the lightbulb button to generate the constructor).
The next problem is that widgets which create a TextEditingController must always be stateful widgets! Otherwise the input made by the user will disappear after every build!
Usually you would pass in the TextEditingController from a parent widget (the widget that handles processes data when you submit it)
Also, it is discouraged to extend widgets. Instead, use composition, e.g.:
class EntradaMail extends StatelessWidget {
final String titulo;
// ...
Widget build(BuildContext context) {
return EntradaDatos(
titulo: titulo,
//...
)
}
}
Widget properties should always be public and final (never start with a _).
You are doing some strange things in CampoEnvio.
First of all, you are for some reason passing in all the properties of the widget to the State in createState. That has some consequences which you probably don't intend.
In general it is extremely rare that your State class has constructor parameters, and usually you would not pass properties from the stateful widget to the state.
The problem is that createState is only called once, it is not called again when you call initState in a parent widget. The state is kept until the widget is disposed.
That means your state constructor is only called once as well, and the fields in _State (of CampoEnvio) will stay the same all the time. Even when the parent is rebuilt and calls the constructor of CampoEnvio again, the old values in _State will not be replaced.
It's also very stange that you are creating widgets (EntradaMail and EntradaMovil) in the StatefulWidget.
The class that extends StatefulWidget should not do that! It is basically just a "bag" of properties.
Here is the complete fixed sample code, following the conventions explained above:
class EntradaDatos extends StatefulWidget {
EntradaDatos({Key key, this.titulo, this.hint, this.validador, this.tit, this.activo}) : super(key: key);
final String titulo;
final String hint;
final String Function(String s) validador;
final TextInputType tit;
final bool activo;
#override
State<StatefulWidget> createState() => _EntradaDatosState();
}
class _EntradaDatosState extends State<EntradaDatos> {
// FocusNode and TextEditingController must be the same for the whole lifetime of the widget
// => put into State
TextEditingController _tec;
FocusNode _fn;
#override
void initState() {
super.initState();
_tec = new TextEditingController();
_fn = new FocusNode();
}
#override
Widget build(BuildContext context) {
print('Construyendo');
return new EnsureVisibleWhenFocused(
focusNode: _fn,
child: new TextFormField(
enabled: widget.activo,
keyboardType: widget.tit,
validator: widget.validador,
autovalidate: true,
focusNode: _fn,
controller: _tec,
decoration: InputDecoration(labelText: widget.titulo, hintText: widget.hint),
));
}
String getContenido() {
return _tec.text;
}
}
class EntradaMail extends StatelessWidget {
static String _hint = "nombre#dominio.es";
static String _validador(String s) {
if (s.isEmpty) {
return 'El campo es obligatorio';
} else {
if (!s.contains('#') || !s.contains('.') || s.contains(' ')) {
return 'Introduce una dirección válida';
} else {
String nombre = s.substring(0, s.indexOf('#'));
String servidor = s.substring(s.indexOf('#') + 1, s.lastIndexOf('.'));
String dominio = s.substring(s.lastIndexOf('.') + 1);
if (nombre.length < 2 || servidor.length < 2 || dominio.length < 2) {
return 'Introduce una dirección válida';
}
}
}
}
EntradaMail({Key key, this.titulo, this.activo}) : super(key: key);
final String titulo;
final bool activo;
#override
Widget build(BuildContext context) {
// use composition instead of inheritance
return EntradaDatos(
titulo: titulo,
activo: activo,
validador: _validador,
hint: _hint,
tit: TextInputType.emailAddress,
);
}
}
class CampoEnvio extends StatefulWidget {
const CampoEnvio({Key key, this.tituloMail, this.tituloMovil}) : super(key: key);
final String tituloMail;
final String tituloMovil;
#override
State<StatefulWidget> createState() => new _CampoEnvioState();
}
class _CampoEnvioState extends State<CampoEnvio> {
// I guess these variables are modified here using setState
bool _usaMail;
bool _usaMovil;
#override
Widget build(BuildContext context) {
// just rebuild the widgets whenever build is called!
final mail = new EntradaMail(
titulo: widget.tituloMail,
activo: _usaMail,
);
final movil = new EntradaMovil(
titulo: widget.tituloMovil,
activo: _usaMovil,
);
return new Column(
children: <Widget>[
new ListTile(
leading: new SizedBox(
width: 70.0,
child: new Row(
children: <Widget>[
new Checkbox(
value: _usaMail,
activeColor: Colors.black,
onChanged: (value) {
setState(() {
_usaMail = value;
});
},
),
],
),
),
title: mail,
),
//...
new Divider()
],
);
}
}
It always helps to look at the official samples in the Flutter repositories!