Android Studio Question posted in
The official documentation can be found here.

Android Studio – error: Undefined name 'context' in flutter

I am a beginner with flutter, I had just started a few days ago. I want to go from one page to another page . But when I use the navigator it shows an error.

I’ve tried to solve it using some answers to similar problems on stack overflow, but I can’t solve it. Also, I am not able to understand those properly.

These are some of them:

Undefined name ‘context’

Undefined name ‘context’ in flutter navigation

import 'package:flutter/material.dart';
import 'package:origitive_app/main.dart';
import 'package:origitive_app/Productpage.dart';

void main() {
  runApp(chooseCategory());
}

class chooseCategory extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
        debugShowCheckedModeBanner: false,
        home: new DefaultTabController(
          length: 3,
          child: new Scaffold(
            appBar: new AppBar(
              title: const Text('Collections'),
              backgroundColor: Colors.grey[400],

              actions: [
                //list if widget in appbar actions
                PopupMenuButton(
                  icon: Icon(Icons.menu),
                  //don't specify icon if you want 3 dot menu
                  color: Colors.blue,
                  itemBuilder: (context) =>
                  [
                    PopupMenuItem<int>(
                      value: 0,
                      child: Text(
                        "Home", style: TextStyle(color: Colors.white),),
                    ),
                    PopupMenuItem<int>(
                      value: 0,
                      child: Text(
                        "About", style: TextStyle(color: Colors.white),),
                    ),
                    PopupMenuItem<int>(
                      value: 0,
                      child: Text(
                        "Settings", style: TextStyle(color: Colors.white),),
                    ),
                  ],
                  onSelected: (item) => {print(item)},
                ),
              ],
              bottom: new TabBar(isScrollable: true, tabs: [
                new Tab(text: 'MEN',),
                new Tab(text: 'WOMEN',),
                new Tab(text: 'KIDS',),
              ]),
            ),
            body: new TabBarView(
              children: [
                new ListView(
                  children: list1,
                ),

                new ListView(
                  children: list2,
                ),
                new ListView(
                  children: list3,
                ),
              ],
            ),

            bottomNavigationBar: BottomNavigationBar(
              type: BottomNavigationBarType.fixed,
              items: const <BottomNavigationBarItem>[
                BottomNavigationBarItem(
                  icon: Icon(Icons.home),
                  title: Text('Home'),
                ),
                BottomNavigationBarItem(
                  icon: Icon(Icons.business),
                  title: Text('Business'),
                ),
                BottomNavigationBarItem(
                  icon: Icon(Icons.computer),
                  title: Text('Technology'),
                ),
                BottomNavigationBarItem(
                  icon: Icon(Icons.book),
                  title: Text('Education'),
                ),
              ],


            ),

          ),
        ));
  }

  List<Widget> list1 = <Widget>[
    new ListTile(
      title: new Text('Shoes',
          style: new TextStyle(fontWeight: FontWeight.w500, fontSize: 20.0)),
      leading: new Image.asset("assets/Images/men1.png"),
      trailing: Icon(Icons.arrow_forward),
      onTap: (){
        Navigator.push(
            context,//error
            MaterialPageRoute(builder: (context) => Productpage()));
      },

    ),
    new ListTile(
      title: new Text('Clothing',
          style: new TextStyle(fontWeight: FontWeight.w500, fontSize: 20.0)),
      subtitle: new Text('429 Castro St'),
      leading: new Image.asset("assets/Images/men2.png"),
      trailing: Icon(Icons.arrow_forward),
      onTap: (){
        Navigator.push(
            context,//error
            MaterialPageRoute(builder: (context) => Productpage()));
      },


    ),
    new ListTile(
      title: new Text('Accessories',
          style: new TextStyle(fontWeight: FontWeight.w500, fontSize: 20.0)),
      leading: new Image.asset("assets/Images/men3.png"),
      trailing: Icon(Icons.arrow_forward),
      onTap: (){
        Navigator.push(
            context,//error
            MaterialPageRoute(builder: (context) => Productpage()));
      },
    ),
  ];

  List<Widget> list2 = <Widget>[
    new ListTile(
      title: new Text('Shoes',
          style: new TextStyle(fontWeight: FontWeight.w500, fontSize: 20.0)),
      subtitle: new Text('85 W Portal Ave'),
      leading: new Image.asset("assets/Images/women1.png"),
      trailing: Icon(Icons.arrow_forward),
      onTap: (){
        Navigator.push(
            context,//error
            MaterialPageRoute(builder: (context) => Productpage()));
      },
    ),
    new ListTile(
      title: new Text('Clothing',
          style: new TextStyle(fontWeight: FontWeight.w500, fontSize: 20.0)),
      leading: new Image.asset("assets/Images/women2.png"),
      trailing: Icon(Icons.arrow_forward),
      onTap: (){
        Navigator.push(
            context,//error
            MaterialPageRoute(builder: (context) => Productpage()));
      },
    ),
    new ListTile(
      title: new Text('Accessories',
          style: new TextStyle(fontWeight: FontWeight.w500, fontSize: 20.0)),
      leading: new Image.asset("assets/Images/women3.png"),
      trailing: Icon(Icons.arrow_forward),
      onTap: (){
        Navigator.push(
            context,//error
            MaterialPageRoute(builder: (context) => Productpage()));
      },
    ),
  ];
  List<Widget> list3 = <Widget>[
    new ListTile(
      title: new Text('Boys Shoes',
          style: new TextStyle(fontWeight: FontWeight.w500, fontSize: 20.0)),
      leading: new Image.asset("assets/Images/boy1.png"),
      trailing: Icon(Icons.arrow_forward),
      onTap: (){
        Navigator.push(
            context,//error
            MaterialPageRoute(builder: (context) => Productpage());
        );
      },
    ),
    new ListTile(
      title: new Text('Girls Shoes',
          style: new TextStyle(fontWeight: FontWeight.w500, fontSize: 20.0)),
      leading: new Image.asset("assets/Images/girl1.png"),
      trailing: Icon(Icons.arrow_forward),
      onTap: (){
        Navigator.push(
            context,//error
            MaterialPageRoute(builder: (context) => Productpage()));
      },
    ),
    new ListTile(
      title: new Text('Boys Clothing',
          style: new TextStyle(fontWeight: FontWeight.w500, fontSize: 20.0)),

         leading: new Image.asset("assets/Images/boy1.png"),
         trailing: Icon(Icons.arrow_forward),
          onTap: () {
            Navigator.push(
                context,//error
                MaterialPageRoute(builder: (context) => Productpage()));
            );
          },
    ),
    new ListTile(
      title: new Text('Girls Clothing',
          style: new TextStyle(fontWeight: FontWeight.w500, fontSize: 20.0)),
      leading: new Image.asset("assets/Images/girl2.png"),
      onTap: (){
        Navigator.push(
            context,//error
            MaterialPageRoute(builder: (context) => Productpage()));
      },trailing: Icon(Icons.arrow_forward),
    ),
  ];
}
}

tried adding a static build context but failed.it gave a null error.

Tags:

4

Answers


  1. 0

    It is because you are trying to access context outside of its scope. Move list1 and list2 to the method build like this:-

    import 'package:flutter/material.dart';
import 'package:origitive_app/main.dart';
import 'package:origitive_app/Productpage.dart';

void main() {
  runApp(chooseCategory());
}

class chooseCategory extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
        debugShowCheckedModeBanner: false,
        home: new DefaultTabController(
          length: 3,
          child: new Scaffold(
            appBar: new AppBar(
              title: const Text('Collections'),
              backgroundColor: Colors.grey[400],

              actions: [
                //list if widget in appbar actions
                PopupMenuButton(
                  icon: Icon(Icons.menu),
                  //don't specify icon if you want 3 dot menu
                  color: Colors.blue,
                  itemBuilder: (context) =>
                  [
                    PopupMenuItem<int>(
                      value: 0,
                      child: Text(
                        "Home", style: TextStyle(color: Colors.white),),
                    ),
                    PopupMenuItem<int>(
                      value: 0,
                      child: Text(
                        "About", style: TextStyle(color: Colors.white),),
                    ),
                    PopupMenuItem<int>(
                      value: 0,
                      child: Text(
                        "Settings", style: TextStyle(color: Colors.white),),
                    ),
                  ],
                  onSelected: (item) => {print(item)},
                ),
              ],
              bottom: new TabBar(isScrollable: true, tabs: [
                new Tab(text: 'MEN',),
                new Tab(text: 'WOMEN',),
                new Tab(text: 'KIDS',),
              ]),
            ),
            body: new TabBarView(
              children: [
                new ListView(
                  children: list1,
                ),

                new ListView(
                  children: list2,
                ),
                new ListView(
                  children: list3,
                ),
              ],
            ),

            bottomNavigationBar: BottomNavigationBar(
              type: BottomNavigationBarType.fixed,
              items: const <BottomNavigationBarItem>[
                BottomNavigationBarItem(
                  icon: Icon(Icons.home),
                  title: Text('Home'),
                ),
                BottomNavigationBarItem(
                  icon: Icon(Icons.business),
                  title: Text('Business'),
                ),
                BottomNavigationBarItem(
                  icon: Icon(Icons.computer),
                  title: Text('Technology'),
                ),
                BottomNavigationBarItem(
                  icon: Icon(Icons.book),
                  title: Text('Education'),
                ),
              ],


            ),

          ),
        ));

        List<Widget> list1 = <Widget>[
    new ListTile(
      title: new Text('Shoes',
          style: new TextStyle(fontWeight: FontWeight.w500, fontSize: 20.0)),
      leading: new Image.asset("assets/Images/men1.png"),
      trailing: Icon(Icons.arrow_forward),
      onTap: (){
        Navigator.push(
            context,//error
            MaterialPageRoute(builder: (context) => Productpage()));
      },

    ),
    new ListTile(
      title: new Text('Clothing',
          style: new TextStyle(fontWeight: FontWeight.w500, fontSize: 20.0)),
      subtitle: new Text('429 Castro St'),
      leading: new Image.asset("assets/Images/men2.png"),
      trailing: Icon(Icons.arrow_forward),
      onTap: (){
        Navigator.push(
            context,//error
            MaterialPageRoute(builder: (context) => Productpage()));
      },


    ),
    new ListTile(
      title: new Text('Accessories',
          style: new TextStyle(fontWeight: FontWeight.w500, fontSize: 20.0)),
      leading: new Image.asset("assets/Images/men3.png"),
      trailing: Icon(Icons.arrow_forward),
      onTap: (){
        Navigator.push(
            context,//error
            MaterialPageRoute(builder: (context) => Productpage()));
      },
    ),
  ];

  List<Widget> list2 = <Widget>[
    new ListTile(
      title: new Text('Shoes',
          style: new TextStyle(fontWeight: FontWeight.w500, fontSize: 20.0)),
      subtitle: new Text('85 W Portal Ave'),
      leading: new Image.asset("assets/Images/women1.png"),
      trailing: Icon(Icons.arrow_forward),
      onTap: (){
        Navigator.push(
            context,//error
            MaterialPageRoute(builder: (context) => Productpage()));
      },
    ),
    new ListTile(
      title: new Text('Clothing',
          style: new TextStyle(fontWeight: FontWeight.w500, fontSize: 20.0)),
      leading: new Image.asset("assets/Images/women2.png"),
      trailing: Icon(Icons.arrow_forward),
      onTap: (){
        Navigator.push(
            context,//error
            MaterialPageRoute(builder: (context) => Productpage()));
      },
    ),
    new ListTile(
      title: new Text('Accessories',
          style: new TextStyle(fontWeight: FontWeight.w500, fontSize: 20.0)),
      leading: new Image.asset("assets/Images/women3.png"),
      trailing: Icon(Icons.arrow_forward),
      onTap: (){
        Navigator.push(
            context,//error
            MaterialPageRoute(builder: (context) => Productpage()));
      },
    ),
  ];
  List<Widget> list3 = <Widget>[
    new ListTile(
      title: new Text('Boys Shoes',
          style: new TextStyle(fontWeight: FontWeight.w500, fontSize: 20.0)),
      leading: new Image.asset("assets/Images/boy1.png"),
      trailing: Icon(Icons.arrow_forward),
      onTap: (){
        Navigator.push(
            context,//error
            MaterialPageRoute(builder: (context) => Productpage());
        );
      },
    ),
    new ListTile(
      title: new Text('Girls Shoes',
          style: new TextStyle(fontWeight: FontWeight.w500, fontSize: 20.0)),
      leading: new Image.asset("assets/Images/girl1.png"),
      trailing: Icon(Icons.arrow_forward),
      onTap: (){
        Navigator.push(
            context,//error
            MaterialPageRoute(builder: (context) => Productpage()));
      },
    ),
    new ListTile(
      title: new Text('Boys Clothing',
          style: new TextStyle(fontWeight: FontWeight.w500, fontSize: 20.0)),

         leading: new Image.asset("assets/Images/boy1.png"),
         trailing: Icon(Icons.arrow_forward),
          onTap: () {
            Navigator.push(
                context,//error
                MaterialPageRoute(builder: (context) => Productpage()));
            );
          },
    ),
    new ListTile(
      title: new Text('Girls Clothing',
          style: new TextStyle(fontWeight: FontWeight.w500, fontSize: 20.0)),
      leading: new Image.asset("assets/Images/girl2.png"),
      onTap: (){
        Navigator.push(
            context,//error
            MaterialPageRoute(builder: (context) => Productpage()));
      },trailing: Icon(Icons.arrow_forward),
    ),
  ];
  }
    Login or Signup to reply.
  2. 0

    Here is a modified code

    import 'package:flutter/material.dart';
import 'package:origitive_app/main.dart';
import 'package:origitive_app/Productpage.dart';

void main() {
  runApp(chooseCategory());
}

class chooseCategory extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
        debugShowCheckedModeBanner: false,
        home: new DefaultTabController(
          length: 3,
          child: new Scaffold(
            appBar: new AppBar(
              title: const Text('Collections'),
              backgroundColor: Colors.grey[400],
              actions: [
                //list if widget in appbar actions
                PopupMenuButton(
                  icon: Icon(Icons.menu),
                  //don't specify icon if you want 3 dot menu
                  color: Colors.blue,
                  itemBuilder: (context) => [
                    PopupMenuItem<int>(
                      value: 0,
                      child: Text(
                        "Home",
                        style: TextStyle(color: Colors.white),
                      ),
                    ),
                    PopupMenuItem<int>(
                      value: 0,
                      child: Text(
                        "About",
                        style: TextStyle(color: Colors.white),
                      ),
                    ),
                    PopupMenuItem<int>(
                      value: 0,
                      child: Text(
                        "Settings",
                        style: TextStyle(color: Colors.white),
                      ),
                    ),
                  ],
                  onSelected: (item) => {print(item)},
                ),
              ],
              bottom: new TabBar(isScrollable: true, tabs: [
                new Tab(
                  text: 'MEN',
                ),
                new Tab(
                  text: 'WOMEN',
                ),
                new Tab(
                  text: 'KIDS',
                ),
              ]),
            ),
            body: new TabBarView(
              children: [
                new ListView(
                  children: list1(context),
                ),
                new ListView(
                  children: list2(context),
                ),
                new ListView(
                  children: list3(context),
                ),
              ],
            ),
            bottomNavigationBar: BottomNavigationBar(
              type: BottomNavigationBarType.fixed,
              items: const <BottomNavigationBarItem>[
                BottomNavigationBarItem(
                  icon: Icon(Icons.home),
                  title: Text('Home'),
                ),
                BottomNavigationBarItem(
                  icon: Icon(Icons.business),
                  title: Text('Business'),
                ),
                BottomNavigationBarItem(
                  icon: Icon(Icons.computer),
                  title: Text('Technology'),
                ),
                BottomNavigationBarItem(
                  icon: Icon(Icons.book),
                  title: Text('Education'),
                ),
              ],
            ),
          ),
        ));
  }

  List<Widget> list1(BuildContext context) => <Widget>[
    new ListTile(
      title: new Text('Shoes',
          style: new TextStyle(fontWeight: FontWeight.w500, fontSize: 20.0)),
      leading: new Image.asset("assets/Images/men1.png"),
      trailing: Icon(Icons.arrow_forward),
      onTap: (){
        Navigator.push(
            context,//error
            MaterialPageRoute(builder: (context) => Productpage()));
      },

    ),
    new ListTile(
      title: new Text('Clothing',
          style: new TextStyle(fontWeight: FontWeight.w500, fontSize: 20.0)),
      subtitle: new Text('429 Castro St'),
      leading: new Image.asset("assets/Images/men2.png"),
      trailing: Icon(Icons.arrow_forward),
      onTap: (){
        Navigator.push(
            context,//error
            MaterialPageRoute(builder: (context) => Productpage()));
      },


    ),
    new ListTile(
      title: new Text('Accessories',
          style: new TextStyle(fontWeight: FontWeight.w500, fontSize: 20.0)),
      leading: new Image.asset("assets/Images/men3.png"),
      trailing: Icon(Icons.arrow_forward),
      onTap: (){
        Navigator.push(
            context,//error
            MaterialPageRoute(builder: (context) => Productpage()));
      },
    ),
  ];

  List<Widget> list2(BuildContext context) => <Widget>[
    new ListTile(
      title: new Text('Shoes',
          style: new TextStyle(fontWeight: FontWeight.w500, fontSize: 20.0)),
      subtitle: new Text('85 W Portal Ave'),
      leading: new Image.asset("assets/Images/women1.png"),
      trailing: Icon(Icons.arrow_forward),
      onTap: (){
        Navigator.push(
            context,//error
            MaterialPageRoute(builder: (context) => Productpage()));
      },
    ),
    new ListTile(
      title: new Text('Clothing',
          style: new TextStyle(fontWeight: FontWeight.w500, fontSize: 20.0)),
      leading: new Image.asset("assets/Images/women2.png"),
      trailing: Icon(Icons.arrow_forward),
      onTap: (){
        Navigator.push(
            context,//error
            MaterialPageRoute(builder: (context) => Productpage()));
      },
    ),
    new ListTile(
      title: new Text('Accessories',
          style: new TextStyle(fontWeight: FontWeight.w500, fontSize: 20.0)),
      leading: new Image.asset("assets/Images/women3.png"),
      trailing: Icon(Icons.arrow_forward),
      onTap: (){
        Navigator.push(
            context,//error
            MaterialPageRoute(builder: (context) => Productpage()));
      },
    ),
  ];

  List<Widget> list3(BuildContext context) => <Widget>[
    new ListTile(
      title: new Text('Boys Shoes',
          style: new TextStyle(fontWeight: FontWeight.w500, fontSize: 20.0)),
      leading: new Image.asset("assets/Images/boy1.png"),
      trailing: Icon(Icons.arrow_forward),
      onTap: (){
        Navigator.push(
            context,//error
            MaterialPageRoute(builder: (context) => Productpage());
        );
      },
    ),
    new ListTile(
      title: new Text('Girls Shoes',
          style: new TextStyle(fontWeight: FontWeight.w500, fontSize: 20.0)),
      leading: new Image.asset("assets/Images/girl1.png"),
      trailing: Icon(Icons.arrow_forward),
      onTap: (){
        Navigator.push(
            context,//error
            MaterialPageRoute(builder: (context) => Productpage()));
      },
    ),
    new ListTile(
      title: new Text('Boys Clothing',
          style: new TextStyle(fontWeight: FontWeight.w500, fontSize: 20.0)),

         leading: new Image.asset("assets/Images/boy1.png"),
         trailing: Icon(Icons.arrow_forward),
          onTap: () {
            Navigator.push(
                context,//error
                MaterialPageRoute(builder: (context) => Productpage()));
            );
          },
    ),
    new ListTile(
      title: new Text('Girls Clothing',
          style: new TextStyle(fontWeight: FontWeight.w500, fontSize: 20.0)),
      leading: new Image.asset("assets/Images/girl2.png"),
      onTap: (){
        Navigator.push(
            context,//error
            MaterialPageRoute(builder: (context) => Productpage()));
      },trailing: Icon(Icons.arrow_forward),
    ),
  ];
}
    Login or Signup to reply.
  3. 0

    In my case I had to convert the widget to a stateful widget to use context inside its state functions (ie outside of build())

    Login or Signup to reply.
  4. 0

    Use- GlobalcontextService

    Step-1

    Create a class like this

        class GlobalcontextServive{
    static Globalkey <NavigatorState> navigatorKey =
    GlobalKey <NavigatorState> ();
    }

    Step-2

    Set navigatorkey in main method

    Can be directly manipulated without first obtaining it from a BuildContext

        MaterialApp(
    navigatorKey: GlobalContextService.navigatorKey,
    )

    Step-3

        Navigator.push(GlobalContextService.navigatorKey.currentContext!, MaterialPageRoute(builder: (context)=>const productpage()));
    Login or Signup to reply.
Please signup or login to give your own answer.

Back To Top
Search