flutter/dart Undefined name 'context'. Try correcting the name to one that is defined, or-CodePudding

I have done IconButton in my main.dart appBar and I want to Navigate using this Icon to my second page named OneDice. When im trying to push it by using

Navigator.of(context).push(MaterialPageRoute(builder: (_) => OneDice(),),);

it doesnt work and I have no idea why.... Can u help me plis? The problem is with (context). Error name is in the topic. And here is mine code. Thanks for all!

import 'package:dicee/OneDice.dart';
import 'package:flutter/material.dart';
import 'dart:math';

void main() {
  return runApp(
    MaterialApp(
      home: Scaffold(
        backgroundColor: Colors.green.shade300,
        body: const DicePage(),
        appBar: AppBar(
          title: const Center(child: Text('Dicee')),
          backgroundColor: Colors.purple,
          elevation: 10.0,
          actions: [
            IconButton(
              onPressed: () {
                Navigator.of(context)
                    .push(MaterialPageRoute(builder: (_) => OneDice(),),);
              },
              icon: const Icon(
                Icons.indeterminate_check_box,
                size: 40,
              ),
            ),
          ],
        ),
      ),
    ),
  );
}

class DicePage extends StatefulWidget {
  const DicePage({Key? key}) : super(key: key);

  @override
  State<DicePage> createState() => _DicePageState();
}

class _DicePageState extends State<DicePage> {
  int leftDiceNumber = 1;
  int rightDiceNumber = 3;

  void rollDice() {
    setState(() {
      leftDiceNumber = Random().nextInt(6)   1;
      rightDiceNumber = Random().nextInt(6)   1;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Center(
      child: Row(
        children: [
          Expanded(
            child: TextButton(
              onPressed: () {
                // when i will press dice it calls Widget build to rebuild
                rollDice();
              },
              child: Image.asset('images/dice$leftDiceNumber.png'),
            ),
          ),
          Expanded(
            child: TextButton(
              onPressed: () {
                rollDice();
              },
              child: Image.asset('images/dice$rightDiceNumber.png'),
            ),
          ),
        ],
      ),
    );
  }
}

CodePudding user response：

You can only access context in the build method. You could do it like this.

void main() {
  return runApp(
    MaterialApp(
      home:MyWidget(),
    ),
  );
}

class MyWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
        backgroundColor: Colors.green.shade300,
        body: const DicePage(),
        appBar: AppBar(
          title: const Center(child: Text('Dicee')),
          backgroundColor: Colors.purple,
          elevation: 10.0,
          actions: [
            IconButton(
              onPressed: () {
                Navigator.of(context)
                    .push(MaterialPageRoute(builder: (_) => OneDice(),),);
              },
              icon: const Icon(
                Icons.indeterminate_check_box,
                size: 40,
              ),
            ),
          ],
        ),
      ),
  }
}

class DicePage extends StatefulWidget {
  const DicePage({Key? key}) : super(key: key);

  @override
  State<DicePage> createState() => _DicePageState();
}

class _DicePageState extends State<DicePage> {
  int leftDiceNumber = 1;
  int rightDiceNumber = 3;

  void rollDice() {
    setState(() {
      leftDiceNumber = Random().nextInt(6)   1;
      rightDiceNumber = Random().nextInt(6)   1;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Center(
      child: Row(
        children: [
          Expanded(
            child: TextButton(
              onPressed: () {
                // when i will press dice it calls Widget build to rebuild
                rollDice();
              },
              child: Image.asset('images/dice$leftDiceNumber.png'),
            ),
          ),
          Expanded(
            child: TextButton(
              onPressed: () {
                rollDice();
              },
              child: Image.asset('images/dice$rightDiceNumber.png'),
            ),
          ),
        ],
      ),
    );
  }
}

CodePudding user response：

You do your piece of code at void main which is totally wrong and the issue here is with Navigator not present in the parent context. You are using a context for the DiceApp which isn't under the navigator. Your working code as below.

void main() {
runApp(const MyApp());
}

class MyApp extends StatelessWidget {
const MyApp({Key? key}) : super(key: key);

@override
Widget build(BuildContext context) {
return MaterialApp(
  title: 'Welcome to Flutter',
  home: Scaffold(
    appBar: AppBar(
      title: Center(child: Text('Dicee')),
       actions: [
        IconButton(
          onPressed: () {
            Navigator.of(context)
                .push(MaterialPageRoute(builder: (_) => OneDice(),),);
          },
          icon: const Icon(
            Icons.indeterminate_check_box,
            size: 40,
          ),
        ),
      ],
    ),
  ),
);
}
}

CodePudding user response：

Just Use

Navigator.push(
 context,
 MaterialPageRoute(builder: (context) => OneDice()),);

And you can also use this code with GetX package

Get.to(() =>  OneDice());