type 'Null' is not a subtype of type 'String' this error pops up when trying to-CodePudding

import 'package:flutter/material.dart';
import 'dart:convert';

class Home extends StatefulWidget {
  @override
  State<Home> createState() => _HomeState();
}

class _HomeState extends State<Home> {

  Map data = {};
  Object? parameters;

  @override
  Widget build(BuildContext context) {

    parameters = ModalRoute.of(context)!.settings.arguments as Map;
    Map data = jsonDecode(jsonEncode(parameters));
    print(data);
    enter code here
    return Scaffold(
      body: SafeArea(
        child: Column(
          children: <Widget>[
            FlatButton.icon(
              onPressed: () {
                Navigator.pushNamed(context,'/location');
              },
              icon: Icon(Icons.edit_location),
              label: Text('Edit Loaction'),
            ),
            SizedBox(height: 20.0),
            Row(
              children: <Widget>[
                Text(
                  data['location']
                )
              ],
            )
          ],
        ),
      ),
    );
  }
}

its showing error

type 'Null' is not a subtype of type 'String'.

This error keeps on poping when I am trying to fetch data fro location from the map. Can anyone tell me the solution for this problem.

CodePudding user response：

Getting arguments can be null

 parameters = ModalRoute.of(context)?.settings.arguments as Map?;
    if (parameters != null) {
      data = jsonDecode(jsonEncode(parameters));
      /// not sure why you need both `jsonDecode` and `jsonEncode`
    }

It is possible to get null while reading map, you can provide default value on null case.

Text(data['location']??"got null")