Error Message: The return type 'void' isn't a 'Widget', as required by the-CodePudding

**Whenever I want to navigate to next page with specific time, the destination page isn,t found, even I imported the page. Instead of Navigation, if I print something, It works OK... Error line is highlighted in bold inside code, Kindly help in this regard.

Thanks in advance for your time and answer.... Whenever I want to navigate to next page with specific time, the destination page isn,t found, even I imported the page. Instead of Navigation, if I print something, It works OK... Error line is highlighted in bold inside code, Kindly help in this regard.

Thanks in advance for your time and answer **

import 'package:flutter/material.dart';
import 'dart:async';
import 'main.dart';

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

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      title: "Flutter App",
      theme: ThemeData(
        appBarTheme: AppBarTheme(
          color: Colors.deepOrangeAccent,
        ),
        primarySwatch: Colors.indigo,
      ),
      home: LoginScreen(),
    );
  }
}

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

  @override
  State<LoginScreen> createState() => _LoginScreenState();
}

class _LoginScreenState extends State<LoginScreen> {

  @override
  void initState() {
    // TODO: implement initState
    super.initState();
    Timer(Duration(seconds: 5), () {
      // 5 seconds over, navigate to Page2.
      **Navigator.of(context).push(MaterialPageRoute(builder: (context)=>main()));****
    });
  }
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.indigo,
      body: Padding(
        //padding: const EdgeInsets.all(20.0),
        padding: const EdgeInsets.symmetric(horizontal: 20.0),
        child: Center(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              Center(
                child: Image.asset(
                  "assets/images/logo.png",
                  //fit: BoxFit.fitWidth,
                  height: 200,
                  width: 200,
                ),
              ),
              //CircularProgressIndicator(),
              SizedBox(
                height: 20,
              ),
              Text(
                "Fresh Food Restaurant",
                style: TextStyle(
                  color: Colors.deepOrangeAccent,
                  fontSize: 25,
                  fontWeight: FontWeight.w900,
                ),
              ),
              SizedBox(
                height: 150,
              ),
              // CircularProgressIndicator(
              //   backgroundColor: Colors.deepOrangeAccent,
              // ),
              // SizedBox(
              //   height: 10,
              // ),
              // Text(
              //   "Loading, Please wait",
              //   style: TextStyle(
              //     color: Colors.white,
              //   ),
              // ),
              SizedBox(
                height: 100,
              ),
              FloatingActionButton(
                backgroundColor: const Color(0xff03dac6),
                foregroundColor: Colors.black,
                onPressed: () {

                },
                child: Icon(Icons.arrow_forward),
              )
            ],
          ),
        ),
      ),
    );
  }
}

CodePudding user response：

Main is not a widget and Navigator need Widget to push, like this:

Timer(Duration(seconds: 5), () {
  Navigator.of(context)
      .push(MaterialPageRoute(builder: (context) => MyApp()));
});

Timer(Duration(seconds: 5), () {
      Navigator.of(context)
          .push(MaterialPageRoute(builder: (context) => LoginScreen()));
    });

but not a method void.

CodePudding user response：

You are trying to navigate to a method:

Navigator.of(context).push(MaterialPageRoute(builder: (context)=>main()));

This method 'main()' is defined above:

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

You have to pay attention to upper and lower case writing (If your widget is called Main()).

CodePudding user response：

Instead of using it in init state use it in Build Widget

      // 5 seconds over, navigate to Page2.
      **Navigator.of(context).push(MaterialPageRoute(builder: (context)=>main()));****
    });

Another MEthod is here

if(mounted){  Future.delayed(Duration(seconds:5)).then((_)=>
    Navigator.of(context).push(MaterialPageRoute(builder: (context)=>main()));
    );}
  }