Please help me. I can't do basic navigation operations
I can't go to my shared page. I don't know why. When I want to route to another page with Navigator.push accrue to an error and I capture my error and add that at bottom of my question.
this is my main page
import 'package:flutter/material.dart';
import 'package:like/shared.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({Key? key}) : super(key: key);
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: homeScreen(context),
);
}
Scaffold homeScreen(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("shared"),
),
body: Center(
child: ElevatedButton(
onPressed: () {
Navigator.push(
context,
MaterialPageRoute(builder: (context) => Shared()),
);
},
child: Text("go")),
),
);
}
}
this is my shared page
import 'package:flutter/material.dart';
import 'package:like/main.dart';
void main() => runApp(Shared());
class Shared extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Material App',
home: Scaffold(
appBar: AppBar(
title: Text('Material App Bar'),
),
body: Center(
child: Container(
child: Text('Hello World'),
),
),
),
);
}
}
Both of them do not work.
For more information about the error, you can see the photo of the error
Navigator.push(
context,
MaterialPageRoute(builder: (context) => Shared()),
);
Shared() is not a widget
remove this line from the top of your page:
import 'package:like/shared.dart';
Shared() is a package
Related
I've followed some online tutorials and managed to implement ChangeNotifier when the app has a single route however none of these explain how to implement this when the app has more than one route (screen) which is rather the point!
I made an attempt to figure this out myself but when the app runs in the emulator I get a blank screen.
/* main.dart */
import 'dart:collection'; // used in test.dart
import 'package:flutter/foundation.dart'; // used in test.dart
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
class Person extends ChangeNotifier {
Person({this.firstName});
String firstName = '';
void updateName(String n) {
this.firstName = n;
notifyListeners();
}
}
void main() {
runApp(
Provider(
create: (_) => Person(firstName: 'Mark'),
child: MaterialApp(
initialRoute: '/',
routes: {
'/': (context) => HomeRoute(),
'/second': (context) => SecondRoute(),
'/third': (context) => ThirdRoute(),
},
),
)
);
}
class HomeRoute extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(Provider.of<Person>(context).firstName),
),
body: Center(
child: new IconButton(
icon: new Icon(Icons.favorite, color: Colors.redAccent),
iconSize: 70.0,
onPressed: () {
Navigator.of(context).pushNamed("/second");
}
),
),
);
}
}
class SecondRoute extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('Second Page'),
),
body: Center(
child: Text(Provider.of<Person>(context).firstName),
),
);
}
}
class ThirdRoute extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('Third Page'),
),
body: Center(
child: Text('Third Route'),
),
);
}
}
The project builds and runs with no error messages which has stumped me.
Any thoughts?
Code developed in FlutLab
Child has an error, I tried invcache/restart, cache restart, nothing happens!!
enter image description here
Try this,let me know it is work for you
Code
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
debugShowCheckedModeBanner: false,
theme: ThemeData(
primarySwatch: Colors.blue,
),
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> {
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
TextButton(
onPressed: () {
_handleClickMe();
},
child: Text(
"CLICK ME!",
),
)
],
),
),
);
}
Future<void> _handleClickMe() async {
return showDialog<void>(
context: context,
barrierDismissible: false, // user must tap button!
builder: (BuildContext context) {
return CupertinoAlertDialog(
title: Text('Alert'),
content: Text("Are you Sure"),
actions: <Widget>[
CupertinoDialogAction(
child: Text('OK'),
onPressed: () {
Navigator.of(context).pop();
},
),
CupertinoDialogAction(
child: Text('Cancel'),
onPressed: () {
Navigator.of(context).pop();
},
),
],
);
},
);
}
}
This should do the trick for you:
showDialog(
context: context,
builder: (BuildContext context){
return CupertinoAlertDialog(
...
)
}
)
you didn't implement builder: (BuildContext, context){ return Widget}
let me know if this works for you :)
I need a dynamic "back" button on every screen/page that also shows the title of the previous screen.
Navigation is done via global navigatorKey, pushing new routes is not done from a specific screen.
Is this possible with built-in navigator or it needs to be built from scratch?
Just pass the string you want to display to the constructor of the widget which will be your next page.
Example:
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
debugShowCheckedModeBanner: false,
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: MyHomePage(),
);
}
}
class MyHomePage extends StatelessWidget {
Widget build(context) {
return Scaffold(
appBar: AppBar(),
body: Center(
child: FlatButton(
onPressed: () {
Navigator.of(context)
.push(MaterialPageRoute(builder: (context) {
return Sec('title1');
}));
},
child: Text('Press here'))));
}
}
Widget backButton(context, t) {
return Row(children: [
Expanded(
child: IconButton(
icon: Icon(Icons.backspace),
onPressed: () => Navigator.pop(context),
),
),
Text(t,style:TextStyle(fontSize:16))
]);
}
class Sec extends StatelessWidget {
String t;
Sec(String x) {
t = x;
}
Widget build(context) {
return Scaffold(
appBar: AppBar(leading: backButton(context, t)),
body: Center(
child: FlatButton(
onPressed: () {
Navigator.pop(context);
},
child: Text('Press here to go back'))));
}
}
Output
I want to make a new route in the flutter , but I failed,
my VS Code give me this:
The following assertion was thrown while handling a gesture:
I/flutter (32582): Navigator operation requested with a context that does not include a Navigator.
I/flutter (32582): The context used to push or pop routes from the Navigator must be that of a widget that is a
I/flutter (32582): descendant of a Navigator widget
import 'package:flutter/material.dart';
void main()=>runApp(MyApp());
class MyApp extends StatelessWidget {
// This widget is the root of your application.
#override
Widget build(BuildContext context) {
return new MaterialApp(
title: 'Lake',
routes: {
'sss': (context)=>new NewRoute()
},
home: new Scaffold(
appBar: AppBar(
title: Text('Lake'),
),
body: Text('BBB'),
floatingActionButton: new FloatingActionButton(
child: Icon(Icons.import_contacts),
onPressed: (){
Navigator.pushNamed(context, 'sss');
},
),
),
);
}
}
class NewRoute extends StatelessWidget{
#override
Widget build(BuildContext context){
return new Scaffold(
appBar: AppBar(
title: Text('BBB'),
),
body: Center(
child: Text('wahaha'),
),
);
}
}
Plea use this code
home: Builder(
builder: (context) => Scaffold(
appBar: AppBar(
title: Text('Lake'),
),
body: Text('BBB'),
floatingActionButton: new FloatingActionButton(
child: Icon(Icons.import_contacts),
onPressed: (){
Navigator.pushNamed(context, 'sss');
},
),
),)
Builder let you build a new context from direct parent like described there https://docs.flutter.io/flutter/widgets/Builder-class.html
You are using routes incorrectly. when you use home in MaterialApp it will bypass the Routes. insted of that you can use initialRoute to define Home Screen
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
// This widget is the root of your application.
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Lake',
routes: {
'sss': (context) => const NewRoute(),
'home': (context) => const HomeScreen(),
},
initialRoute: 'home',
);
}
}
class HomeScreen extends StatelessWidget {
const HomeScreen({Key? key}) : super(key: key);
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('Lake'),
),
body: const Text('BBB'),
floatingActionButton: FloatingActionButton(
child: const Icon(Icons.import_contacts),
onPressed: () {
Navigator.pushNamed(context, 'sss');
},
),
);
}
}
class NewRoute extends StatelessWidget {
const NewRoute({Key? key}) : super(key: key);
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('BBB'),
),
body: const Center(
child: Text('wahaha'),
),
);
}
}
also avoid using new keyword.
you can also try with onGenarated Routes in flutter.
more information
when returning MaterialApp flutter shows error as follow "error: 1 required argument(s) expected, but 0 found. (not_enough_required_arguments at [demo] lib/main.dart:9)"Here is the screenshot
const _categoryName = "Cake";
const _categoryIcon = Icons.cake;
const _categoryColor = Colors.green;
import 'package:solution_02_category_widget/category.dart';
void main() {
runApp(UnitConverterApp());
}
class UnitConverterApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
debugShowCheckedModeBanner: false,
title: 'Unit Converter',
home: Scaffold(
backgroundColor: Colors.green[100],
body: Center(
child: Category(
name: _categoryName,
color: _categoryColor,
iconLocation: _categoryIcon,
),
),
),
);
}
}
You should wrap the title argument under AppBar Widget. You can in turn wrap the appBar argument inside the Scaffold. The scaffold is like an empty page that gives your app the white background. Below is a sample code implementation:
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
// debugShowMaterialGrid: true,
theme: ThemeData(
brightness: Brightness .light,
accentColor: Colors.deepPurple,
primarySwatch: Colors.deepOrange),
home: Scaffold(
appBar: AppBar(
title: Text('Some text'),
),
),
);
}
}
Your code is working fine without error if i remove the Category() widget. The below code is working fine:
import 'package:flutter/material.dart';
const _categoryName = "Cake";
const _categoryIcon = Icons.cake;
const _categoryColor = Colors.green;
void main() {
runApp(UnitConverterApp());
}
class UnitConverterApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
debugShowCheckedModeBanner: false,
title: 'Unit Converter',
home: Scaffold(
backgroundColor: Colors.green[100],
body: Center(
child: Container(),
),
),
);
}
}
Maybe the problem is in the Category() widget so if you post it i can check it for you.