在有状态小部件中按路线名称进行颤动导航

Question

i am trying to go on another page using navigation, but i am getting error;

Navigator operation requested with a context that does not include a Navigator.

i am just trying to move on next page, i followed flutter documentations for this stateless widget but how to do with state full widget.

import 'package:flutter/material.dart';

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

class MyApp extends StatefulWidget {
  @override
  State createState() => new MyApp1();
}

class MyApp1 extends State<MyApp> {
  List<Widget> _listSection = [];

  Widget build(BuildContext context) {
   return MaterialApp(
      debugShowCheckedModeBanner: false,
      title: 'Share IDEASS',
      initialRoute: '/',
  routes: {
    '/second': (context) => SecondScreen(),
  },
      home: Scaffold(
        appBar: AppBar(
          title: Text('IDEAS'),
        ),
        body: Container(
          child: Stack(
            children: [
              floatingButton(),
            ],
          ),
        ),
      ),
    );
  }



  Widget floatingButton() {
    return Container(
      padding: const EdgeInsets.all(30),
      alignment: Alignment.bottomRight,
      child: FloatingActionButton(
        onPressed: () {
            Navigator.pushNamed(context, "/SecondScreen");
          },
        child: Text("+"),
        backgroundColor: Colors.blue,
      ),
    );
  }
}
class SecondScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("Second Route"),
      ),
      body: Center(
        child: RaisedButton(
          onPressed: () {
            Navigator.pop(context);
          },
          child: Text('Go back!'),
        ),
      ),
    );
  }
}

Answer 1

You should use the named route you created.

Widget floatingButton(BuildContext context) { // added context as a parameter
    return Container(
      padding: const EdgeInsets.all(30),
      alignment: Alignment.bottomRight,
      child: FloatingActionButton(
        onPressed: () {
            Navigator.pushNamed(context, "/second"); // Changed this to use the named route
          },
        child: Text("+"),
        backgroundColor: Colors.blue,
      ),
    );
  }
}

then use the following

body: Container(
          child: Stack(
            children: [
              floatingButton(context),
            ],
          ),
        ),

Answer 2

The situation here is that the floatingButton() uses a context with the navigator to push the given page route. But the context used is provided in the parent Widget( MaterialApp ) it self, which doesn't include a Navigator, hence the error.

So, Try this approach: Separate the Home widget from the MaterialApp, like below:

return MaterialApp(
      debugShowCheckedModeBanner: false,
      title: 'Share IDEASS',
      initialRoute: '/',
      routes: {
        '/second': (context) => SecondScreen(),
      },
      home: HomePage(),
    );

Create a stateless widget containing the Scaffold:

class HomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('IDEAS'),
      ),
      body: Container(
        child: Stack(
          children: [
            floatingButton(),
          ],
        ),
      ),
    );
  }
}

Hope it helps. Let me know if this doesn't work.

Answer 3

You have made two mistakes because of which your code is not working:

1. You have used wrong route name. Replace /SecondScreen with /second
2. You have used wrong context. You can get Navigator only if your widget has MaterialApp as it's parent and here you are using context of MyApp1 so it is not working.

Following is a working code for your reference.

---

import 'package:flutter/material.dart';

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

class MyApp extends StatefulWidget {
  @override
  State createState() => new MyApp1();
}

class MyApp1 extends State<MyApp> {
  List<Widget> _listSection = [];

  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      title: 'Share IDEASS',
      initialRoute: '/',
      routes: {
        '/second': (context) => SecondScreen(),
      },
      home: AppContent(),
    );
  }
}

class AppContent extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('IDEAS'),
      ),
      body: Container(
        child: Stack(
          children: [
            floatingButton(context),
          ],
        ),
      ),
    );
  }

  Widget floatingButton(BuildContext context) {
    return Container(
      padding: const EdgeInsets.all(30),
      alignment: Alignment.bottomRight,
      child: FloatingActionButton(
        onPressed: () {
          Navigator.pushNamed(context, "/second");
        },
        child: Text("+"),
        backgroundColor: Colors.blue,
      ),
    );
  }
}

class SecondScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("Second Route"),
      ),
      body: Center(
        child: RaisedButton(
          onPressed: () {
            Navigator.pop(context);
          },
          child: Text('Go back!'),
        ),
      ),
    );
  }
}