Testing again to format the flutter code. Triple backticks failed in here trying this other method

 

dart

Copy code

import 'package:flutter/material.dart'; import 'package:google_fonts/google_fonts.dart';
import 'package:todolist/pages/tasklist/tasklist.dart'; import 'package:todolist/pages/tasklistdetails/tasklistdetails.dart';
void main() {   runApp(const MyApp()); }
class MyApp extends StatelessWidget {   const MyApp({super.key});
  @override   Widget build(BuildContext context) {     return MaterialApp(         title: 'Flutter Demo',         theme: ThemeData(           primarySwatch: Colors.blue,           textTheme: GoogleFonts.robotoCondensedTextTheme(),         ),         initialRoute: '/tasklist',         routes: {           '/tasklist': ((context) =>               const TaskListPage(title:"Task List1 Page")),           '/tasklistdetails': ((context) =>               const TaskListDetailsPage(title: "Task List Details Page"))         });   } }
class MyHomePage extends StatefulWidget {   const MyHomePage({super.key, required this.title});   final String title;   @override   State<MyHomePage> createState() => _MyHomePageState(); }
class _MyHomePageState extends State<MyHomePage> {   @override   Widget build(BuildContext context) {     return Scaffold(       appBar: AppBar(         title: Text(widget.title),       ),       body: const Text('Task list page'),       floatingActionButton: Theme(         data: Theme.of(context).copyWith(splashColor: Colors.amber),         child: FloatingActionButton(           onPressed: () =>{Navigator.pop(context)},           tooltip: 'Increment',           child: const Icon(Icons.add),         ),       ), // This trailing comma makes auto-formatting nicer for build methods.     );   } }

Using Flutter Version 3.3.6 - 

My code below - I got this message which I don't understand

No MediaQuery widget ancestor found.
Scaffold widgets require a MediaQuery widget ancestor.
The specific widget that could not find a MediaQuery ancestor was:
  Scaffold
The ownership chain for the affected widget is: "Scaffold ← FoodList ← [root]"
No MediaQuery ancestor could be found starting from the context that was passed to MediaQuery.of(). This can happen because you have not added a WidgetsApp, CupertinoApp, or MaterialApp widget (those widgets introduce a MediaQuery), or it can happen if the context you use comes from a widget above those widgets.

import 'package:flutter/material.dart';
void main() {runApp(const FoodList());}

class FoodList extends StatelessWidget {
const FoodList({super.key});

@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text("Food List"),
),
body: ListView(
children: const <Widget>[
ListTile(
title: Text("Food Item 1"),
trailing: Checkbox(value: false, onChanged: null),
),
ListTile(
title: Text("Food Item 2"),
trailing: Checkbox(value: false, onChanged: null),
),
ListTile(
title: Text("Food Item 3"),
trailing: Checkbox(value: false, onChanged: null),
),
ListTile(
title: Text("Food Item 4"),
trailing: Checkbox(value: false, onChanged: null),
),
ListTile(
title: Text("Food Item 5"),
trailing: Checkbox(value: false, onChanged: null),
),
ElevatedButton(
onPressed: null,
child: Text('Submit'),
)
],
),
);
}
}

How to resolve this error message in flutter - library_private_types_in_public_api

The line of code it's complaining is  this -

_MyPageState createState() => _MyPageState();



The flutter code lines - class MyPage extends StatefulWidget {
const MyPage({super.key});

@override
_MyPageState createState() => _MyPageState();
}

Thanks to everyone for there help on my previous question.

Using Flutter ver 3.3.8 and Android Studio Dolphin | 2021.3.1 Patch 1 (This is the latest version that i'm using. Since the book is using an older version.)

Modified the Widget with this code see below

Still having issues with this line of code -

if (inValue?.isEmpty) {
return "Please enter username";
}

Flutter shows this msg - A nullable expression can't be used as a condition. Try checking that the value isn't 'null' before using it as a condition. See screenshot of the message listed below. A;so put the full code below the screenshot.

import 'package:flutter/material.dart';

void main() {

runApp(const MyApp());

}



class MyApp extends StatefulWidget {

const MyApp({super.key});

@override

_MyApp createState() => _MyApp();

}


class LoginData {

String username = "";

String password = "";



}



class _MyApp extends State {



LoginData loginData = LoginData();

final GlobalKey<FormState> _formkey = GlobalKey<FormState>();



@override

Widget build(BuildContext inContext) {

return MaterialApp(home: Scaffold(

body : Container(

padding : const EdgeInsets.all(50.0),

child : Form(

key: _formkey,

child: Column(

children: [

TextFormField(

keyboardType: TextInputType.emailAddress,

validator: (String? inValue) {

if (inValue?.isEmpty) {
return "Please enter username";
}

return null;

},
onSaved: (String inValue) {
loginData.username = inValue;
},

decoration: const InputDecoration(
hintText: "[email protected]",
labelText: "Username (eMail address)"
),
),

TextFormField(

obscureText: true,

validator: (String inValue) {
if (inValue.length < 10) {
return "Password must be >=10 in length";
}
return null;
},

onSaved: (String inValue) {
this.loginData.password = inValue;
},

decoration: InputDecoration(
hintText : "Password",
labelText : "Password"
),
),

ElevatedButton(

child : Text("Log In!"),

onPressed: (){

if (_formkey.currentState.validate()){

_formkey.currentState.save();

print ("Username: ${_loginData.username}");

print ("Password: ${_loginData.password}");

}

},

),

]

),

),

),

));

}

}