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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!
Anyone here know Flutter/Dart
i have a defaultLayout which looks a little bit like this
final title = Data.appTitle;
var pages = [HomeScreen(), SearchPage(), LivePage(), AccountPage()];
String _currentRoute;
#override
Widget build(BuildContext context) {
return new Scaffold(
appBar: new AppBar(
title: new Text(title),
),
body: childViewBody(), //each class that extends Default() can modify this method to change body
//...Other Layout. BotAppBar is a custom widget
bottomNavigationBar: BotAppBar(
onTap: (index) {
setState(() {
//HERE... How can I make that whenever the BotAppBarItems are selected,.. the body is updated
});
},
items: [
BotAppBarItem(iconData: Icons.home, tooltip: Data.homeTitle),
BotAppBarItem(iconData: Icons.search, tooltip: Data.searchTitle),
BotAppBarItem(iconData: Icons.near_me, tooltip: Data.liveTitle),
BotAppBarItem(iconData: Icons.account_circle, tooltip: Data.accountTitle),
],
),
);
}
//Child class will modify this area to update screen.
childViewBody() {
return Column(
children: <Widget>[
Text('Placeholder')
],
);
}
... And this should update for any class that's extended it
for example
class HomePage extends Default {//...super}
class HomePageState extends DefaultState {
#override
String get title => Data.homeTitle; //updates title in parent class
childViewBody() {
return Column{
//Build HomeScreen Body here
}
}
}
Diagram.png
so how would i modify Default class that whenever the BotAppBar is selected, the body is updated... even if the current class loaded is a child class
You can use HeroAnimations
to open a new window over your previous window as this is how SearchWindows should be displayed to the user.
Here's a tutorial to implement it.
If HeroAnimations sounds bit too much,
use Navigation
Directions:
Create two screens
Navigate to the second screen using Navigator.push
Return to the first screen using Navigator.pop
Example
import 'package:flutter/material.dart';
void main() {
runApp(MaterialApp(
title: 'Navigation Basics',
home: FirstScreen(),
));
}
class FirstScreen extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('First Screen'),
),
body: Center(
child: RaisedButton(
child: Text('Launch screen'),
onPressed: () {
Navigator.push(
context,
MaterialPageRoute(builder: (context) => SecondScreen()),
);
},
),
),
);
}
}
class SecondScreen extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("Second Screen"),
),
body: Center(
child: RaisedButton(
onPressed: () {
Navigator.pop(context);
},
child: Text('Go back!'),
),
),
);
}
}
As title. It since that we can detect the drawer is opened, but is this possible to check it is closed or not? Thanks.
I have added this feature in Flutter 2.0.0. Make sure you are using Flutter SDK version >= 2.0.0 to use this.
Simply use a callback in Scaffold
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
drawer: NavDrawer(),
onDrawerChanged: (isOpen) {
// write your callback implementation here
print('drawer callback isOpen=$isOpen');
},
endDrawer: NavDrawerEnd(),
onEndDrawerChanged: (isOpen) {
// write your callback implementation here
print('end drawer callback isOpen=$isOpen');
},
body:
...
Pull request merged in 2.0.0: https://github.com/flutter/flutter/pull/67249
Happy coding!
Declare a GlobalKey to reference your drawer:
GlobalKey _drawerKey = GlobalKey();
Put the key in your Drawer:
drawer: Drawer(
key: _drawerKey,
Check if your drawer is visible:
final RenderBox box = _drawerKey.currentContext?.findRenderObject();
if (box != null){
//is visible
} else {
//not visible
}
You can copy paste run full code below
You can wrap Drawer with a StatefulWidget and put callback in initState() and dispose()
initState() will call widget.callback(true); means open
dispose() will call widget.callback(false); means close
Slide also work in this case
code snippet
drawer: CustomDrawer(
callback: (isOpen) {
print("isOpen ${isOpen}");
WidgetsBinding.instance.addPostFrameCallback((_) {
setState(() {
_isDrawerOpen = isOpen;
});
});
},
...
class CustomDrawer extends StatefulWidget {
CustomDrawer({
Key key,
this.elevation = 16.0,
this.child,
this.semanticLabel,
this.callback,
}) : assert(elevation != null && elevation >= 0.0),
super(key: key);
final double elevation;
final Widget child;
final String semanticLabel;
final DrawerCallback callback;
#override
_CustomDrawerState createState() => _CustomDrawerState();
}
class _CustomDrawerState extends State<CustomDrawer> {
#override
void initState() {
if (widget.callback != null) {
widget.callback(true);
}
super.initState();
}
#override
void dispose() {
if (widget.callback != null) {
widget.callback(false);
}
super.dispose();
}
#override
Widget build(BuildContext context) {
return Drawer(
key: widget.key,
elevation: widget.elevation,
semanticLabel: widget.semanticLabel,
child: widget.child);
}
}
working demo
full code
import 'package:flutter/material.dart';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
visualDensity: VisualDensity.adaptivePlatformDensity,
),
home: MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
final String title;
#override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
bool _isDrawerOpen = false;
int _counter = 0;
void _incrementCounter() {
setState(() {
_counter++;
});
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
drawer: CustomDrawer(
callback: (isOpen) {
print("isOpen ${isOpen}");
WidgetsBinding.instance.addPostFrameCallback((_) {
setState(() {
_isDrawerOpen = isOpen;
});
});
},
child: ListView(
padding: EdgeInsets.zero,
children: <Widget>[
DrawerHeader(
child: Text('Drawer Header'),
decoration: BoxDecoration(
color: Colors.blue,
),
),
ListTile(
title: Text('Item 1'),
onTap: () {
Navigator.push(
context,
MaterialPageRoute(builder: (context) => SecondRoute()),
);
},
),
ListTile(
title: Text('Item 2'),
onTap: () {
// Update the state of the app.
// ...
},
),
],
),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Align(
alignment: Alignment.centerRight,
child: Text(
_isDrawerOpen.toString(),
),
),
Text(
'You have pushed the button this many times:',
),
Text(
'$_counter',
style: Theme.of(context).textTheme.headline4,
),
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: _incrementCounter,
tooltip: 'Increment',
child: Icon(Icons.add),
), // This trailing comma makes auto-formatting nicer for build methods.
);
}
}
class CustomDrawer extends StatefulWidget {
CustomDrawer({
Key key,
this.elevation = 16.0,
this.child,
this.semanticLabel,
this.callback,
}) : assert(elevation != null && elevation >= 0.0),
super(key: key);
final double elevation;
final Widget child;
final String semanticLabel;
final DrawerCallback callback;
#override
_CustomDrawerState createState() => _CustomDrawerState();
}
class _CustomDrawerState extends State<CustomDrawer> {
#override
void initState() {
if (widget.callback != null) {
widget.callback(true);
}
super.initState();
}
#override
void dispose() {
if (widget.callback != null) {
widget.callback(false);
}
super.dispose();
}
#override
Widget build(BuildContext context) {
return Drawer(
key: widget.key,
elevation: widget.elevation,
semanticLabel: widget.semanticLabel,
child: widget.child);
}
}
class SecondRoute extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("route test"),
),
body: Text("SecondRoute"));
}
}
You can simply use onDrawerChanged for detecting if the drawer is opened or closed in the Scaffold widget.
Property :
{void Function(bool)? onDrawerChanged}
Type: void Function(bool)?
Optional callback that is called when the Scaffold.drawer is opened or closed.
Example :
#override Widget build(BuildContext context) {
return Scaffold(
onDrawerChanged:(val){
if(val){
setState(() {
//foo bar;
});
}else{
setState(() {
//foo bar;
});
}
},
drawer: Drawer(
child: Container(
)
));
}
When you click a Drawer Item where you will navigate to a new screen, there in the Navigator.push(..) call, you can add a .then(..) clause, and then know when the Drawer item Screen has been popped.
Here is the ListTile for a Drawer item which makes the Navigator.push(..) call when clicked , and the the associated .then(..) callback block:
ListTile(
title: Text('About App'),
onTap: () {
Navigator.push(
_ctxt,
MaterialPageRoute(builder: (context) => AboutScreen()),
).then(
(value) {
print('Drawer callback for About selection');
if (_onReadyCallback != null) {
_onReadyCallback();
}
},
);
}),
_onReadyCallback() represents a Function param you can pass in.
I found this is approach - of leveraging the .then() callback from a .push() call - to be a very useful concept to understand with Flutter in general.
Big thanks to the main 2 answers here:
Force Flutter navigator to reload state when popping
Here's the complete Drawer code:
Drawer drawer = Drawer(
child: ListView(
padding: EdgeInsets.zero,
children: <Widget>[
DrawerHeader(
decoration: BoxDecoration(
color: Color(0xFF7FAD5F),
),
child: Text(App.NAME_MENU),
),
ListTile(
title: Text('About App'),
onTap: () {
Navigator.push(
_ctxt,
MaterialPageRoute(builder: (context) => AboutScreen()),
).then(
(value) {
print('Drawer callback for About selection');
if (_onReadyCallback != null) {
_onReadyCallback();
}
},
);
}),
],
),
);
I would recommend that you use this package : https://pub.dev/packages/visibility_detector.
Afterwards you should assign a GlobalKey, like _drawerKey for instance, to the Drawer widget, after which you would be able to detect when the drawer is closed like this:
VisibilityDetector(
key: _drawerKey,
child: Container(),
onVisibilityChanged: (info) {
if (info.visibleFraction == 0.0) {
// drawer not visible.
}
},
)
I'm trying to create a Radio in a showDialog, however the animation that occurs on Radio does not appear in showDialog.
For example: when tapped in foo2 nothing happens, and when you exit in showDialog and go back to it, foo2 is selected.
Below is the code and a gif showing what is happening:
import "package:flutter/material.dart";
void main() {
runApp(new ControlleApp());
}
class ControlleApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return new MaterialApp(
title: "My App",
home: new HomePage(),
);
}
}
class HomePage extends StatefulWidget {
#override
HomePageState createState() => new HomePageState();
}
enum _RadioGroup {
foo1,
foo2
}
class HomePageState extends State<HomePage> {
_RadioGroup _itemType = _RadioGroup.foo1;
void changeItemType(_RadioGroup type) {
setState(() {
_itemType = type;
});
}
void showDemoDialog<T>({ BuildContext context, Widget child }) {
showDialog<T>(
context: context,
child: child,
);
}
#override
Widget build(BuildContext context){
return new Scaffold(
appBar: new AppBar(backgroundColor: new Color(0xFF26C6DA)),
body: new Container(
child: new Row(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
new InkWell(
onTap: (){
showDemoDialog<String>(
context: context,
child: new SimpleDialog(
title: const Text("show"),
children: <Widget>[
new Row(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
new Radio<_RadioGroup>(
groupValue: _itemType,
value: _RadioGroup.foo1,
onChanged: changeItemType
),
const Text("foo1"),
new Radio<_RadioGroup>(
groupValue: _itemType,
value: _RadioGroup.foo2,
onChanged: changeItemType
),
const Text("foo2"),
],
)
],
)
);
},
child: new Container(
margin: new EdgeInsets.only(top: 16.0, bottom: 8.0),
child: new Text("Show"),
),
)
],
),
)
);
}
}
Remember that components are immutable.
When you call showDialog, the content of that dialog won't change even if HomePage does.
The solution is easy. You need to refactor a bit your code to something like :
showDialog(
context: context,
builder: (context) => MyForm()
)
and instead of changing the state of HomePage, you instead change the state of MyForm.
example :
class Test extends StatelessWidget {
void onSubmit(String result) {
print(result);
}
#override
Widget build(BuildContext context) {
return Scaffold(
body: Center(
child: RaisedButton(
onPressed: () => showDialog(context: context, builder: (context) => MyForm(onSubmit: onSubmit)),
child: Text("dialog"),
),
),
);
}
}
typedef void MyFormCallback(String result);
class MyForm extends StatefulWidget {
final MyFormCallback onSubmit;
MyForm({this.onSubmit});
#override
_MyFormState createState() => _MyFormState();
}
class _MyFormState extends State<MyForm> {
String value = "foo";
#override
Widget build(BuildContext context) {
return SimpleDialog(
title: Text("My form"),
children: <Widget>[
Radio(
groupValue: value,
onChanged: (value) => setState(() => this.value = value),
value: "foo",
),
Radio(
groupValue: value,
onChanged: (value) => setState(() => this.value = value),
value: "bar",
),
FlatButton(
onPressed: () {
Navigator.pop(context);
widget.onSubmit(value);
},
child: new Text("submit"),
)
],
);
}
}