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I'm making Notes app. I made cards with text and buttons dynamically (Create by clicking the button). But I have problem with Changing Text on CURRENT card. For example, I have 3 cards with own texts and buttons and I want to change text on 2nd card but text is changing on the 3rd card. How can I solve this problem?
3 cards with texts and buttons
Change Text Page
In the past, I've tried making list to collect texts, but i dont know how to identify current card.
full main.dart
import 'package:flutter/material.dart';
import './changeTextPage.dart';
int count = 0;
String titlecard = '';
String textcard = '';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Notes',
theme: ThemeData(
primarySwatch: Colors.deepPurple
),
home: HomePage(title: 'Notes',),
);
}
}
class HomePage extends StatefulWidget {
HomePage({Key key, this.title}) : super(key: key);
final title;
#override
HomePageState createState() => HomePageState();
}
class HomePageState extends State<HomePage> {
#override
Widget build(BuildContext context) {
List<Widget> cards = new List.generate(count, (int i) => new MyCard());
return Scaffold(
appBar: AppBar(
title: Text('Notes'),
),
body: LayoutBuilder(
builder: (context, constraint) {
return Column(
children: <Widget>[
Container(
height: 650.0,
child: new ListView(
children: cards,
scrollDirection: Axis.vertical,
),
),
],
);
}
),
floatingActionButton: FloatingActionButton(
child: Icon(Icons.add),
onPressed: () {
setState(() {
Navigator.push(context, MaterialPageRoute(
builder: (context) => changeText())
);
});
},
),
);
}
}
class MyCard extends StatefulWidget {
#override
myCard createState() => myCard();
}
class myCard extends State<MyCard> {
int myCount = count;
void click() {
setState(() {
Navigator.push(context, MaterialPageRoute(
builder: (context) => setNewText())
);
});
}
#override
Widget build(BuildContext context) {
return Center(
child: Card(
child: Column(
mainAxisSize: MainAxisSize.min,
children: <Widget>[
ListTile(
leading: Icon(Icons.album),
title: Text(titlecard),
subtitle: Text(textcard),
),
ButtonTheme.bar( // make buttons use the appropriate styles for cards
child: ButtonBar(
children: <Widget>[
FlatButton(
child: const Text('Change Text'),
onPressed: click,
),
FlatButton(
child: const Text('LISTEN'),
onPressed: () { /* ... */ },
),
],
),
),
],
),
),
);
}
}
class setNewText extends StatefulWidget {
#override
SetNewText createState() => SetNewText();
}
class SetNewText extends State<setNewText> {
final titleController = TextEditingController();
final textController = TextEditingController();
final formkey = GlobalKey<FormState>();
void _submit() {
setState(() {
if (formkey.currentState.validate()) {
formkey.currentState.save();
Navigator.pop(context);
titlecard = titleController.text;
textcard = textController.text;
}
});
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Change Title'),
),
body: Column(
children: <Widget>[
Card(
child: Padding(
padding: EdgeInsets.all(2.0),
child: Form(
key: formkey,
child: Column(
children: <Widget>[
TextFormField(
controller: titleController,
decoration: InputDecoration(
labelText: 'Title'
),
validator: (value) => value.length < 1 ? 'Invalid Title' : null,
onSaved: (value) => value = titleController.text,
),
TextFormField(
controller: textController,
decoration: InputDecoration(
labelText: 'Text'
),
validator: (text) => text.length < 1 ? 'Invalid Text' : null,
onSaved: (text) => text = textController.text,
)
],
),
),
),
),
FlatButton(
textColor: Colors.deepPurple,
child: Text('SUBMIT'),
onPressed: _submit,
),
],
)
);
}
}
changeTextPage.dart
import 'package:flutter/material.dart';
import './main.dart';
class changeText extends StatefulWidget {
#override
ChangeText createState() => ChangeText();
}
class ChangeText extends State<changeText> {
myCard s = myCard();
final titleController = TextEditingController();
final textController = TextEditingController();
final formkey = GlobalKey<FormState>();
void _submit() {
setState(() {
if (formkey.currentState.validate()) {
formkey.currentState.save();
Navigator.pop(context);
count++;
titlecard = titleController.text;
textcard = textController.text;
}
});
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Change Title'),
),
body: Column(
children: <Widget>[
Card(
child: Padding(
padding: EdgeInsets.all(2.0),
child: Form(
key: formkey,
child: Column(
children: <Widget>[
TextFormField(
controller: titleController,
decoration: InputDecoration(
labelText: 'Title'
),
validator: (value) => value.length < 1 ? 'Invalid Title' : null,
onSaved: (value) => value = titleController.text,
),
TextFormField(
controller: textController,
decoration: InputDecoration(
labelText: 'Text'
),
validator: (text) => text.length < 1 ? 'Invalid Text' : null,
onSaved: (text) => text = textController.text,
)
],
),
),
),
),
FlatButton(
textColor: Colors.deepPurple,
child: Text('SUBMIT'),
onPressed: _submit,
),
],
)
);
}
}
Okay, so you happen to make some common mistakes, one of which is critical.
most importantly don't use global variables! As you do with count, titlecard and textcard.
there is a practice to name stateful widgets with PascalCase and corresponding states just like the widget but prefixed with an underscore (_) to make it private and suffixed by the State word.
The correct approach for this (or one of them) would be to have a widget that would be your screen with a form to edit stuff and it would pop some struct with user values on submit:
class ChangeTextScreen extends StatefulWidget {
_ChangeTextScreenState createState() => _ChangeTextScreenState();
}
class _ChangeTextScreenState extends State<ChangeTextScreen> {
void _submit() {
setState(() {
formkey.currentState.save();
Navigator.pop(ChangeTextResult(title: titleController.text, text: textController.text));
});
}
// Rest of your code...
}
class ChangeTextResult {
final String title;
final String text;
ChangeTextResult({#required this.title, #required this.text});
}
You should also have a place where you store your notes in some kind of a list. Your main screen looks like a good place for it. Once your app will be bigger, think about using scoped_model or Redux or something.
So let's add a Note class and a list with your notes to your main screen:
class Note {
String title;
String text;
Note(this.title, this.text);
}
class HomePageState extends State<HomePage> {
List<Note> _notes = [Note('Test', 'Some test note')];
#override
Widget build(BuildContext context) {
ListView cards = ListView.builder(
itemCount: _notes.length,
itemBuilder: (context, index) => MyCard(
title: _notes[index].title,
text: _notes[index].text,
onEdit: (title, text) => setState(() { // We'll get back to that later
_notes[index].title = title;
_notes[index].text = text;
})
));
// (...)
Your MyCard widget (try to use better names next time) should contain some kind of information about its content, one of the best approaches would be to pass this info to its constructor, just like that:
class MyCard extends StatefulWidget {
final String title;
final String text;
final Function onEdit;
MyCard({Key key, #required this.title, #required this.text, #required this.onEdit}) : super(key: key);
#override
_MyCardState createState() => _MyCardState();
}
Having this Key parameter is a good practice.
And use those parameters in your _MyCardState class (I renamed it from _myCard):
// (...)
children: <Widget>[
ListTile(
leading: Icon(Icons.album),
title: Text(widget.title),
subtitle: Text(widget.text),
),
// (...)
Returning to the moment where you open your ChangeTextScreen, you should assign the result of Navigation.push() to a variable. This is your result, you can deal with it (once we check it for null, the user could have returned from this screen and then the result would be null).
void click() {
setState(() {
final ChangeTextResult result = Navigator.push(context, MaterialPageRoute(
builder: (context) => ChangeTextScreen())
);
if (result != null) {
widget.onEdit(result.title, result.text);
}
});
}
Do you remember that onEdit parameter (I mentioned it in a comment in the code above)? We call that parameter here.
That's it I think. I could have mixed some concepts of your app, but I think you'll manage to get my point anyways.
I quite rewrote all of your code. I think it will be easier for you to start again from scratch and have those tips in mind. Also, try to Google some similar things (like a simple Todo application) or do Getting started from flutter.io with part two! That should give you a nice idea on how to resolve that common problem in Flutter.
And also, read about good practises in Flutter and Dart. Things like correctly formatting your code are really important.
BTW that's my longest answer on Stack Overflow so far. I hope you'll appreciate that.
I'm trying to start a new screen within an onTap but I get the following error:
Navigator operation requested with a context that does not include a
Navigator.
The code I am using to navigate is:
onTap: () { Navigator.of(context).pushNamed('/settings'); },
I have set up a route in my app as follows:
routes: <String, WidgetBuilder>{
'/settings': (BuildContext context) => new SettingsPage(),
},
I've tried to copy the code using the stocks sample application. I've looked at the Navigator and Route documentation and can't figure out how the context can be made to include a Navigator. The context being used in the onTap is referenced from the parameter passed into the build method:
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
SettingsPage is a class as follows:
class SettingsPage extends Navigator {
Widget buildAppBar(BuildContext context) {
return new AppBar(
title: const Text('Settings')
);
}
#override
Widget build(BuildContext context) {
return new Scaffold(
appBar: buildAppBar(context),
);
}
}
TLDR: Wrap the widget which needs to access to Navigator into a Builder or extract that sub-tree into a class. And use the new BuildContext to access Navigator.
This error is unrelated to the destination. It happens because you used a context that doesn't contain a Navigator instance as parent.
How do I create a Navigator instance then ?
This is usually done by inserting in your widget tree a MaterialApp or WidgetsApp. Although you can do it manually by using Navigator directly but less recommended. Then, all children of such widget can access NavigatorState using Navigator.of(context).
Wait, I already have a MaterialApp/WidgetsApp !
That's most likely the case. But this error can still happens when you use a context that is a parent of MaterialApp/WidgetsApp.
This happens because when you do Navigator.of(context), it will start from the widget associated to the context used. And then go upward in the widget tree until it either find a Navigator or there's no more widget.
In the first case, everything is fine. In the second, it throws a
Navigator operation requested with a context that does not include a Navigator.
So, how do I fix it ?
First, let's reproduce this error :
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
home: Center(
child: RaisedButton(
child: Text("Foo"),
onPressed: () => Navigator.pushNamed(context, "/"),
),
),
);
}
}
This example creates a button that attempts to go to '/' on click but will instead throw an exception.
Notice here that in the
onPressed: () => Navigator.pushNamed(context, "/"),
we used context passed by to build of MyApp.
The problem is, MyApp is actually a parent of MaterialApp. As it's the widget who instantiate MaterialApp! Therefore MyApp's BuildContext doesn't have a MaterialApp as parent!
To solve this problem, we need to use a different context.
In this situation, the easiest solution is to introduce a new widget as child of MaterialApp. And then use that widget's context to do the Navigator call.
There are a few ways to achieve this. You can extract home into a custom class :
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
home: MyHome()
);
}
}
class MyHome extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Center(
child: RaisedButton(
child: Text("Foo"),
onPressed: () => Navigator.pushNamed(context, "/"),
),
);
}
}
Or you can use Builder :
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
home: Builder(
builder: (context) => Center(
child: RaisedButton(
child: Text("Foo"),
onPressed: () => Navigator.pushNamed(context, "/"),
),
),
),
);
}
}
Hy guys, i have the same problem. This is occur for me. The solution what i found is very simple. Only what i did is in a simple code:
void main() {
runApp(MaterialApp(
home: YOURAPP() ,
),
);
}
I hope was useful.
Make sure your current parent widget not with same level with MaterialApp
Wrong Way
class HomeScreen extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
appBar: AppBar(
centerTitle: true,
title: Text('Title'),
),
body: Center(
child: Padding(
padding: EdgeInsets.symmetric(vertical: 8.0, horizontal: 16.0),
child: RaisedButton(
onPressed: () {
//wrong way: use context in same level tree with MaterialApp
Navigator.push(context,
MaterialPageRoute(builder: (context) => ScanScreen()));
},
child: const Text('SCAN')),
)),
),
);
}
}
Right way
void main() => runApp(MaterialApp(
title: "App",
home: HomeScreen(),
));
class HomeScreen extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
centerTitle: true,
title: Text('Title'),
),
body: Center(
child: Padding(
padding: EdgeInsets.symmetric(vertical: 8.0, horizontal: 16.0),
child: RaisedButton(
onPressed: () {
//right way: use context in below level tree with MaterialApp
Navigator.push(context,
MaterialPageRoute(builder: (context) => ScanScreen()));
},
child: const Text('SCAN')),
)),
);
}
}
Just like with a Scaffold you can use a GlobalKey. It doesn't need context.
final _navKey = GlobalKey<NavigatorState>();
void _navigateToLogin() {
_navKey.currentState.popUntil((r) => r.isFirst);
_navKey.currentState.pushReplacementNamed(LoginRoute.name);
}
#override
Widget build(BuildContext context) {
return MaterialApp(
navigatorKey: _navKey,
...
);
}
I set up this simple example for routing in a flutter app:
import 'package:flutter/material.dart';
void main() {
runApp(new MyApp());
}
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return new MaterialApp(
title: 'Flutter Demo',
home: new MyHomePage(),
routes: <String, WidgetBuilder>{
'/settings': (BuildContext context) => new SettingsPage(),
},
);
}
}
class MyHomePage extends StatelessWidget {
#override
Widget build(BuildContext context) {
return new Scaffold(
appBar: new AppBar(
title: new Text('TestProject'),
),
body: new Center(
child: new FlatButton(
child: const Text('Go to Settings'),
onPressed: () => Navigator.of(context).pushNamed('/settings')
)
)
);
}
}
class SettingsPage extends StatelessWidget {
#override
Widget build(BuildContext context) {
return new Scaffold(
appBar: new AppBar(
title: new Text('SettingsPage'),
),
body: new Center(
child: new Text('Settings')
)
);
}
}
Note, that the SettingsPage extends StatelessWidget and not Navigator. I'm not able to reproduce your error.
Does this example help you in building your app? Let me know if I can help you with anything else.
You should rewrite your code in main.dart
FROM:
void main() => runApp(MyApp());
TO
void main() {
runApp(MaterialApp(
title: 'Your title',
home: MyApp(),));}
The point is to have the home property to be your first page
this worked for me, I hope it will help someone in the future
A complete and tested solution:
import 'dart:async';
import 'package:flutter/material.dart';
import 'package:my-app/view/main-view.dart';
class SplashView extends StatelessWidget {
#override
Widget build(BuildContext context) {
return new MaterialApp(
home: Builder(
builder: (context) => new _SplashContent(),
),
routes: <String, WidgetBuilder>{
'/main': (BuildContext context) => new MainView()}
);
}
}
class _SplashContent extends StatefulWidget{
#override
_SplashContentState createState() => new _SplashContentState();
}
class _SplashContentState extends State<_SplashContent>
with SingleTickerProviderStateMixin {
var _iconAnimationController;
var _iconAnimation;
startTimeout() async {
var duration = const Duration(seconds: 3);
return new Timer(duration, handleTimeout);
}
void handleTimeout() {
Navigator.pushReplacementNamed(context, "/main");
}
#override
void initState() {
super.initState();
_iconAnimationController = new AnimationController(
vsync: this, duration: new Duration(milliseconds: 2000));
_iconAnimation = new CurvedAnimation(
parent: _iconAnimationController, curve: Curves.easeIn);
_iconAnimation.addListener(() => this.setState(() {}));
_iconAnimationController.forward();
startTimeout();
}
#override
Widget build(BuildContext context) {
return new Center(
child: new Image(
image: new AssetImage("images/logo.png"),
width: _iconAnimation.value * 100,
height: _iconAnimation.value * 100,
)
);
}
}
As per this comment If your navigator is inside Material context navigator push will give this error. if you create a new widget and assign it to the material app home navigator will work.
This won't work
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return new MaterialApp(
home: new Scaffold(
appBar: new AppBar(
title: new Text("Title"),
),
body: new Center(child: new Text("Click Me")),
floatingActionButton: new FloatingActionButton(
child: new Icon(Icons.add),
backgroundColor: Colors.orange,
onPressed: () {
print("Clicked");
Navigator.push(
context,
new MaterialPageRoute(builder: (context) => new AddTaskScreen()),
);
},
),
),
);
}
}
This will work
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return new MaterialApp(
home: new HomeScreen());
}
}
class HomeScreen extends StatelessWidget {
#override
Widget build(BuildContext context) {
return new Scaffold(
appBar: new AppBar(
title: new Text("Title"),
),
body: new Center(child: new Text("Click Me")),
floatingActionButton: new FloatingActionButton(
child: new Icon(Icons.add),
backgroundColor: Colors.orange,
onPressed: () {
print("Clicked");
Navigator.push(
context,
new MaterialPageRoute(builder: (context) => new AddTaskScreen()),
);
},
),
);
}
}
I was facing the same problem and solved by removing home from MaterialApp and use initialRoute instead.
return MaterialApp(
debugShowCheckedModeBanner: false,
initialRoute: '/',
routes: {
'/': (context) => MyApp(),
'/settings': (context) => SettingsPage(),
},
);
And
onTap: () => {
Navigator.pushNamed(context, "/settings")
},
It is Simple
instead using this normal code
`runApp(BasicBankingSystem());`
wrap it with MaterialApp
runApp(MaterialApp(home: BasicBankingSystem()));
It happens because the context on the widget that tries to navigate is still using the material widget.
The short answer for the solution is to :
extract your widget
that has navigation to new class so it has a different context when calling the navigation
When your screen is not navigated from other screen,you don't initially have access to the navigator,Because it is not instantiated yet.So in that case wrap your widget with builder and extract context from there.This worked for me.
builder: (context) => Center(
child: RaisedButton(
child: Text("Foo"),
onPressed: () => Navigator.pushNamed(context, "/"),
),
You ca use this plugin
https://pub.dev/packages/get/versions/2.0.2
in The MaterialApp assign property navigatorKey: Get.key,
MaterialApp(
navigatorKey: Get.key,
initialRoute: "/",
);
you can access Get.toNamed("Your route name");
Change your main function example:
void main() {
runApp(
MaterialApp(
title: 'Your title',
home: MyApp(),
)
);
}
use this
void main() {
runApp(MaterialApp(debugShowCheckedModeBanner: false, home: MyApp()),);
}
instead of this
void main() {runApp(MyApp());}
Wrap with materialapp
reproduce code
import 'dart:convert';
import 'package:flutter/material.dart';
void main() {
// reproduce code
runApp(MyApp());
// working switch //
// runApp(
//
// MaterialApp(debugShowCheckedModeBanner: false, home: MyApp()),);
}
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
debugShowCheckedModeBanner: false,
home: Scaffold(
body:
Column(mainAxisAlignment: MainAxisAlignment.center, children: [
Row(
mainAxisAlignment: MainAxisAlignment.center,
children: [
Container(
height: 100,
width: 100,
child: ElevatedButton(
onPressed: () {
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => IntroPage(Isscar4: true)),
);
},
child: RichText(
text: TextSpan(
text: 'CAR',
style: TextStyle(
letterSpacing: 3,
color: Colors.white,
fontWeight: FontWeight.w400),
children: [
TextSpan(
text: '4',
style: TextStyle(
fontSize: 25,
color: Colors.red,
fontWeight: FontWeight.bold))
],
)),
),
),
],
),
SizedBox(
height: 10,
),
Row(
mainAxisAlignment: MainAxisAlignment.center,
children: [
Container(
height: 100,
width: 100,
child: ElevatedButton(
onPressed: () {
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => IntroPage(Isscar4: false)),
);
},
child: RichText(
text: TextSpan(
text: 'BIKE',
style: TextStyle(
letterSpacing: 3,
color: Colors.white,
fontWeight: FontWeight.w400),
children: [
TextSpan(
text: '2',
style: TextStyle(
fontSize: 25,
color: Colors.red,
fontWeight: FontWeight.bold))
],
)),
),
),
],
)
])));
}
MaterialApp Swithwidget(istrue) {
return MaterialApp(
home: Scaffold(
body: IntroPage(
Isscar4: istrue,
),
),
);
}
}
class Hi extends StatelessWidget {
const Hi({Key? key}) : super(key: key);
#override
Widget build(BuildContext context) {
return Container(
child: Text("df"),
);
}
}
class IntroPage extends StatelessWidget {
final Isscar4;
IntroPage({
Key? key,
required this.Isscar4,
}) : super(key: key);
List<Widget> listPagesViewModel = [];
List<IntroModel> models = [];
#override
Widget build(BuildContext context) {
List<dynamic> intro = fetchIntroApi(Isscar4);
intro.forEach((element) {
var element2 = element as Map<String, dynamic>;
var cd = IntroModel.fromJson(element2);
models.add(cd);
});
models.forEach((element) {
listPagesViewModel.add(Text(""));
});
return MaterialApp(
debugShowCheckedModeBanner: false,
home: Scaffold(
body: Container(),
));
}
List fetchIntroApi(bool bool) {
var four = bool;
if (four) {
var data =
'[ {"name_Title": "title name1","description": "description1"}, {"name_Title": "title name2","description": "description2"}, {"name_Title": "title name3","description": "description3"}, {"name_Title": "title name4","description": "description4"} ]';
return json.decode(data);
} else {
var data =
'[ {"name_Title": "title name","description": "description1"}, {"name_Title": "title name2","description": "description2"}, {"name_Title": "title name3","description": "description3"} ]';
return json.decode(data);
}
}
}
class IntroModel {
String? nameTitle;
String? description;
IntroModel({this.nameTitle, this.description});
IntroModel.fromJson(Map<String, dynamic> json) {
nameTitle = json['name_Title'];
description = json['description'];
}
Map<String, dynamic> toJson() {
final Map<String, dynamic> data = new Map<String, dynamic>();
data['name_Title'] = this.nameTitle;
data['description'] = this.description;
return data;
}
}
class Splash extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Splash Screen',
theme: ThemeData(
primarySwatch: Colors.green,
),
home: MyState(),
debugShowCheckedModeBanner: false,
);
}
void main() {
runApp(Splash());
}
class MyState extends StatefulWidget{
#override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyState> {
#override
void initState() {
super.initState();
Timer(Duration(seconds: 3),
()=>Navigator.pushReplacement(context,
MaterialPageRoute(builder:
(context) =>
Login()
)
)
);
}
#override
Widget build(BuildContext context) {
return Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center ,
children: [
Container(
child:
Image.asset("assets/images/herosplash.png"),
),
],
),
);
}
}
Builder(
builder: (context) {
return TextButton(
child: const Text('Bearbeiten'),
onPressed:(){
Navigator.push(
context,
MaterialPageRoute(builder: (context) => const gotothesiteyouwant()),
);
});
}
),
Here, all you need is to make MaterialApp the parent of your Build. This is because the context that you've used to navigate to a different screen is finding a MaterialApp or a WidgetApp as a parent of the build.
And Since in your case, the situation is the opposite, therefore you need to modify it by either calling a new Stateless widget the parent of is the MaterialApp or by simply using a Builder as home: Builder in MaterialApp.
Hope this would help!
Alright, i have a big issue with this.
Most of the Questions with similar issues, didn't quite help me cause they had a very different approach.
I'm trying to edit the data in a Profile. Im using a Map to access the Data.
Now when i try to set the new Map an Error appears: "Only static members can be accessed in initializers."
i show you all the code. its not everything and i changed some parts to see better what i mean. i hope you guys understand it.
class Tabs extends StatefulWidget {
Tabs({this.infos});
final Map<String, dynamic> info;
#override
State<StatefulWidget> createState() {
return _Tabs();
}
}
class _Tabs extends State<Tabs> {
int _currentIndex = 0; //Bottom Navigation
final List<Widget> _children = [
MaterialApp(
theme: ThemeData(
primaryColor: Colors.white,
primaryColorDark: Colors.cyan[700],
primaryColorLight: Colors.cyan[200],
accentColor: Colors.deepOrange[200],
),
home: Suche(), //not important..
),
Center(child: Text("2")), //some dummy page
Chats(),// some other dummy page
Profile(userInformationen: _infosTabs, updateProfile: _updateProfile), //the Profile Page plus the Error appears "Only static members can be accessed in initializers."
];
void _updateProfil(Map<String, dynamic> newMap) {
setState(() {
_infos = newMap;
});
} //here i want to update the info i receive
final Map<String, dynamic> _infos = ({
'title': "Title",
'name': "name",
'points': 73,
'about me': "texttexttexttexttext"
});
class Profile extends StatelessWidget {
Profile({this.userInformationen, this.updateProfile});
final Map<String, dynamic> userInformationen;
final Function updateProfile;
#override
Widget build(BuildContext context) {
double containerHight = 8.0;
return Scaffold(
drawer: Drawer(
child: Scaffold(
appBar: AppBar(
automaticallyImplyLeading: false,
title: Text("Info"),
),
body: ListView(
children: <Widget>[
ListTile(
leading: Icon(Icons.settings),
title: Text("Profil bearbeiten"),
onTap: () {
Navigator.push(
context,
MaterialPageRoute(
builder: (BuildContext context) => EditProfile(
updateProfile: updateProfile),
),
],
),
],
),
),
);
}
}
class EditProfile extends StatefulWidget {
final Function updateProfile;
EditProfile({this.updateProfile});
#override
State<StatefulWidget> createState() {
return _EditProfileStae();
}
}
class _EditProfileState extends State<EditProfile> {
_EditProfileState();
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: Text('Edit Profile')),
body: Container(
margin: EdgeInsets.all(16.0),
child: Form(
child: ListView(
children: <Widget>[
TextField(
),
RaisedButton(
child: Text("Save"),
onPressed: () {
widget.updateProfile({
'title': 'Title',
'name': 'some name',
'points': 69,
'about': "texttexttext"
});
Navigator.pushReplacement(
context,
MaterialPageRoute(
builder: (BuildContext context) => Tabs(),
),
);
},
),
],
),
),
),
);
}
}
i dont know may be i have a complet wrong approach or its just a little mistake.
You need to do something like the following. I replaced some of the widgets you didn't define with just Text.
Note that children is no longer final, you need to set it in initState. Also note that _infos cannot be final if you want to use the _updateProfile in the way you have it currently defined.
class _Tabs extends State<Tabs> {
List<Widget> _children;
void _updateProfile(Map<String, dynamic> newMap) {
setState(() {
_infos = newMap;
});
} //here i want to update the info i receive
Map<String, dynamic> _infos = ({
'title': "Title",
'name': "name",
'points': 73,
'about me': "texttexttexttexttext"
});
#override
void initState() {
_children = [
MaterialApp(
theme: ThemeData(
primaryColor: Colors.white,
primaryColorDark: Colors.cyan[700],
primaryColorLight: Colors.cyan[200],
accentColor: Colors.deepOrange[200],
),
home: Text(''), //not important..
),
Center(child: Text("2")), //some dummy page
Text(''), // some other dummy page
Profile(
userInformationen: _infosTabs,
updateProfile:
_updateProfile), //the Profile Page plus the Error appears "Only static members can be accessed in initializers."
];
super.initState();
}
}
How to fix this For loop not working error? for loop only work once in Flutter
It's a simple login form. If username and password matched go to user
page else go to admin page.
method code:
checkLogin(){
setState(() {
for(var c=0;c < global.user_name_arr.length-1 ; c++){
if(global.user_name_arr[c]==myController.text&&global.user_password_arr[c]==myControllerPwd.text)
Navigator.push(context, MaterialPageRoute(builder: (context)=>user()),);
else
Navigator.push(context, MaterialPageRoute(builder:(context)=>admin()),); }
}); }
RaiseButton code:
new RaisedButton(
child:new Text("Click"),
onPressed:checkLogin,
)
global.dart
library user_login.globlas;
var user_name_arr=['bhanuka','isuru','sampath'];
var user_password_arr=['1234','123','12'];
First off, let's refactor your code :) Create a user class like so:
class User {
final String name;
final String password;
User(this.name, this.password);
}
Next, fix your global user collection:
final validUsers = [User('bhanuka', '1234'), User('isuru', '123'), User('sampath', '12')];
Now, use this code to perform correct navigation:
checkLogin() {
if (validUsers.indexWhere((user) => user.name == myController.text && user.password == myControllerPwd.text) >= 0) {
Navigator.push(context, MaterialPageRoute(builder: (context)=>user()),);
} else {
Navigator.push(context, MaterialPageRoute(builder:(context)=>admin()),);
}
}
There are better ways to do this comparison but I guess it's good enough for your use case.
here you are using if else so that condition is right or wrong one of the part is executed.
import 'package:flutter/material.dart';
void main() => runApp(new MaterialApp(
title: 'Forms in Flutter',
home: new LoginPage(),
));
class LoginPage extends StatefulWidget {
#override
State<StatefulWidget> createState() => new _LoginPageState();
}
class _LoginData {
String email = '';
String password = '';
}
class _LoginPageState extends State<LoginPage> {
final GlobalKey<FormState> _formKey = new GlobalKey<FormState>();
_LoginData _data = new _LoginData();
var user_name_arr = ['bhanuka', 'isuru', 'sampath'];
var user_password_arr = ['1234', '123', '12'];
var p;
void submit() {
if (this._formKey.currentState.validate()) {
_formKey.currentState.save(); // Save our form now.
if (user_name_arr.contains(_data.email)) {
p = user_name_arr.indexOf(_data.email);
if (user_password_arr.elementAt(p) == _data.password) {
Navigator.push(context, MaterialPageRoute(builder: (context)=>user()),);
} else {
Navigator.push(
context,
MaterialPageRoute(builder: (context) => admin()),
);
}
} else {
Navigator.push(
context,
MaterialPageRoute(builder: (context) => admin()),
);
}
}
}
#override
Widget build(BuildContext context) {
final Size screenSize = MediaQuery.of(context).size;
return new Scaffold(
appBar: new AppBar(
title: new Text('Login'),
),
body: new Container(
padding: new EdgeInsets.all(20.0),
child: new Form(
key: this._formKey,
child: new ListView(
children: <Widget>[
new TextFormField(
keyboardType: TextInputType
.emailAddress, // Use email input type for emails.
decoration: new InputDecoration(
hintText: 'you#example.com',
labelText: 'E-mail Address'),
onSaved: (String value) {
this._data.email = value;
}),
new TextFormField(
obscureText: true, // Use secure text for passwords.
decoration: new InputDecoration(
hintText: 'Password', labelText: 'Enter your password'),
onSaved: (String value) {
this._data.password = value;
}),
new Container(
width: screenSize.width,
child: new RaisedButton(
child: new Text(
'Login',
style: new TextStyle(color: Colors.white),
),
onPressed: this.submit,
color: Colors.blue,
),
margin: new EdgeInsets.only(top: 20.0),
)
],
),
)),
);
}
}
class user extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Scaffold(
body: Container(
child: Center(child: new Text("user")),
),
);
}
}
class admin extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Scaffold(
body: Container(
child: Center(child: new Text("admin")),
),
);
}
}
I'm trying to create a SimpleDialog that allows the user to enter their name. But when it is displayed the dialog is half hidden by the on-screen keyboard:
How can I get the Dialog to be fully visible?
Edit: I find it strange that the homepage widget (FocusVisibilityDemo) recognises the reduced height and therefore adjusts the position of the 'Push Me' button to remain in the center. Unfortunately the dialog doesn't behave the same way.
Here is my code:
import 'package:flutter/material.dart';
class FocusVisibilityDemo extends StatefulWidget {
#override
_FocusVisibilityDemoState createState() => new _FocusVisibilityDemoState();
}
class _FocusVisibilityDemoState extends State<FocusVisibilityDemo> {
#override
Widget build(BuildContext context) {
return new Scaffold(
appBar: new AppBar(title: new Text('Text Dialog Demo')),
body: new Center(
child: new RaisedButton(
onPressed: _showDialog,
child: new Text("Push Me"),
),
),
);
}
_showDialog() async {
await showDialog<String>(
context: context,
child: new AlertDialog(
contentPadding: const EdgeInsets.all(16.0),
content: new Row(
children: <Widget>[
new Expanded(
child: new TextField(
autofocus: true,
decoration: new InputDecoration(
labelText: 'Full Name', hintText: 'eg. John Smith'),
),
)
],
),
actions: <Widget>[
new FlatButton(
child: const Text('CANCEL'),
onPressed: () {
Navigator.pop(context);
}),
new FlatButton(
child: const Text('OPEN'),
onPressed: () {
Navigator.pop(context);
})
],
),
);
}
}
void main() {
runApp(new MaterialApp(home: new FocusVisibilityDemo()));
}
If your use case is to add multiple TextFields inside your Dialog so your main Form does not get crowded, I think it is better if you build something more customizable than AlertDialog and SimpleDialog as they are used for simple activities (confirmations, radios..etc).
Otherwise, why do you want to use a Dialog for a single TextField ?
When we add multiple TextFields we should be careful about our design choices since other people will interact with this view to fill in the data, in this case I prefer to use fullscreenDialog property of PageRoute class. I am not sure if SimpleDialog can be suitable for that in Flutter.
Here is a quick example on how to use a FullScreenDialog, I hope this help and you should be able to modify it the way you want:
import 'package:flutter/material.dart';
void main() {
runApp(new MaterialApp(home: new MyApp(),));
}
class MyApp extends StatefulWidget {
#override
MyAppState createState() => new MyAppState();
}
class MyAppState extends State<MyApp> {
FullScreenDialog _myDialog = new FullScreenDialog();
#override
Widget build(BuildContext context) {
return new Scaffold(
appBar: new AppBar(
title: new Text("Fill this form"),
),
body: new Column(
children: <Widget>[
new TextField(controller: new TextEditingController(
text: "Add a single text field"),),
new Card(child: new ListTile(
title: new Text("Click to add your top 3 amazing skills"),
subtitle: new Text(
"${_myDialog._skillOne} ${_myDialog._skillTwo} ${_myDialog
._skillThree}"),
onTap: () {
Navigator.push(context, new MaterialPageRoute(
builder: (BuildContext context) => _myDialog,
fullscreenDialog: true,
));
},
),
),
],
)
);
}
}
class FullScreenDialog extends StatefulWidget {
String _skillOne = "You have";
String _skillTwo = "not Added";
String _skillThree = "any skills yet";
#override
FullScreenDialogState createState() => new FullScreenDialogState();
}
class FullScreenDialogState extends State<FullScreenDialog> {
TextEditingController _skillOneController = new TextEditingController();
TextEditingController _skillTwoController = new TextEditingController();
TextEditingController _skillThreeController = new TextEditingController();
#override
Widget build(BuildContext context) {
return new Scaffold(
appBar: new AppBar(
title: new Text("Add your top 3 skills"),
),
body: new Padding(child: new ListView(
children: <Widget>[
new TextField(controller: _skillOneController,),
new TextField(controller: _skillTwoController,),
new TextField(controller: _skillThreeController,),
new Row(
children: <Widget>[
new Expanded(child: new RaisedButton(onPressed: () {
widget._skillThree = _skillThreeController.text;
widget._skillTwo = _skillTwoController.text;
widget._skillOne = _skillOneController.text;
Navigator.pop(context);
}, child: new Text("Save"),))
],
)
],
), padding: const EdgeInsets.symmetric(horizontal: 20.0),)
);
}
}
EDIT
After doing some research, it seems that this is a bug in the current Flutter version, the temporary fix is also documented in this issue.
import 'package:flutter/material.dart';
void main() {
runApp(new MaterialApp(home: new FocusVisibilityDemo()));
}
class FocusVisibilityDemo extends StatefulWidget {
#override
_FocusVisibilityDemoState createState() => new _FocusVisibilityDemoState();
}
class _FocusVisibilityDemoState extends State<FocusVisibilityDemo> {
#override
Widget build(BuildContext context) {
return new Scaffold(
appBar: new AppBar(title: new Text('Text Dialog Demo')),
body: new Center(
child: new RaisedButton(
onPressed: _showDialog,
child: new Text("Push Me"),
),
),
);
}
_showDialog() async {
await showDialog<String>(
context: context,
child: new _SystemPadding(child: new AlertDialog(
contentPadding: const EdgeInsets.all(16.0),
content: new Row(
children: <Widget>[
new Expanded(
child: new TextField(
autofocus: true,
decoration: new InputDecoration(
labelText: 'Full Name', hintText: 'eg. John Smith'),
),
)
],
),
actions: <Widget>[
new FlatButton(
child: const Text('CANCEL'),
onPressed: () {
Navigator.pop(context);
}),
new FlatButton(
child: const Text('OPEN'),
onPressed: () {
Navigator.pop(context);
})
],
),),
);
}
}
class _SystemPadding extends StatelessWidget {
final Widget child;
_SystemPadding({Key key, this.child}) : super(key: key);
#override
Widget build(BuildContext context) {
var mediaQuery = MediaQuery.of(context);
return new AnimatedContainer(
padding: mediaQuery.viewInsets,
duration: const Duration(milliseconds: 300),
child: child);
}
}