Question 91725 in Flutter Question posted in
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how can correct this error " Expected a value of type 'Map<dynamic, dynamic>', but got one of type 'Null' " – Flutter

import ‘package:flutter/material.dart’;

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

@override
State createState() => _HomeState();
}

class _HomeState extends State {
Map? data = {};

@override
void initState() {

super.initState();

}

@override
Widget build(BuildContext context) {

final Map data =  ModalRoute.of(context)!.settings.arguments as Map;
print(data);





return Scaffold(
  body: SafeArea(
    child: Padding(
      padding: const EdgeInsets.fromLTRB(0, 120, 0, 0),
      child: Column(
        children: [
          TextButton.icon(
            onPressed: () {
              Navigator.pushNamed(context,'/location');
            }, 
            icon: const Icon(Icons.edit_location),  
            label: const Text('Edit Location'),
            ),
            const SizedBox(height: 20,),
            Row(
              mainAxisAlignment: MainAxisAlignment.center,
              children: [
                Text(
                  data['location'],
                  style: const TextStyle(
                    fontSize: 20.0,
                    letterSpacing: 2,

                  ),
                )
              ],
              ),
            const SizedBox(height: 20,),
            Text(
              data['time'],
              style: const TextStyle(
                fontSize: 66,
              ),
            ),
        ],
      ),
    ),
    ),
);

}
}

{location: Berlin, flag: germany.jpg, time: 9:08 AM}

Tags:

2

Answers


  1. 0

    try with

    final Map? data =  ModalRoute.of(context)!.settings.arguments as Map;

    By this Null safety operator you are telling the returned value could be null as well. Once the value is received handle the null value as per your requirement.

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  2. 0

    you have to replace Map with a custom class,

    final Map? data =  ModalRoute.of(context)!.settings.arguments as Map;

    class ScreenArguments {
  final String title;
  final String message;

  ScreenArguments(this.title, this.message);
}

final ScreenArguments? data =  ModalRoute.of(context)!.settings.arguments as ScreenArguments;

    you have to pass arguments at pushNamed function

                TextButton.icon(
              onPressed: () {
                Navigator.pushNamed(context,'/location', arguments: ScreenArguments("halo", "Message"));
              },
              icon: const Icon(Icons.edit_location),
              label: const Text('Edit Location'),
            ),

    you have also to place appBar:AppBar() in Scaffold for back Button
    it can be empty

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