EXCEPTION CAUGHT BY WIDGETS LIBRARY The following _TypeError was thrown: ): type 'Null' is not a subtype of type 'bool'

Question

I'm getting error. i want to update time after time being selected. as i'm new to flutter i'm unable to understand the flutter. I'm leaving pages that i've worked.

Main.dart

import 'package:flutter/material.dart';
import 'pages/choose_location.dart';
import 'pages/home.dart';
import 'pages/loading.dart';

void main() => runApp(MaterialApp(
  initialRoute: '/loading', // Change the initialRoute to a valid route
  routes: {
    '/loading': (context) => Loading(),
    '/home': (context) => const Home(),
    '/location': (context) => const ChooseLocation(),
  },
  // Add a home argument for the default route (optional)
  home: Loading(), // You can choose a different widget if needed
));

pages/world_time.dart

import 'package:http/http.dart';
import 'dart:convert';
import 'package:intl/intl.dart';

class WorldTime {
  String location;
  String flag;
  String url;
  String time;
  bool isDaytime;

  WorldTime({
    required this.location,
    required this.flag,
    required this.url,
    required this.time,
    required this.isDaytime,
  });

  Future<void> getTime() async {
    try {
      var uri = Uri.http('worldtimeapi.org', '/api/timezone/$url');
      var response = await get(uri);
      Map data = jsonDecode(response.body);

      // Getting properties from data
      String dateTime = data["datetime"];
      String offset = data["utc_offset"].substring(1, 3);

      // Create datetime object
      DateTime now = DateTime.parse(dateTime);
      now = now.add(Duration(hours: int.parse(offset)));
          isDaytime = now.hour > 6 && now.hour < 20 ? true : false;
          time = DateFormat.jm().format(now);
    } catch (e) {
      print('Caught error: $e');
      time = 'Could not get time data';
    }
  }
}

WorldTime instance = WorldTime(
  location: 'berlin',
  flag: 'germany',
  time: '',
  url: 'Europe/Berlin',
  isDaytime: true, // Set isDaytime here
);

pages/home.dart

import 'package:flutter/material.dart';

class Home extends StatefulWidget {
  const Home({Key? key}) : super(key: key);
  @override
  State<Home> createState() => _HomeState();
}

class _HomeState extends State<Home> {
  Map data = {};

  @override
  Widget build(BuildContext context) {
    data = data.isNotEmpty ? data : ModalRoute.of(context)?.settings.arguments as Map; // Corrected type casting
    print(data);
    //set background
    Color? bgColor = data['isDaytime'] ? Colors.blue : Colors.indigo[700];
      return Scaffold(
      backgroundColor: bgColor,
      body: SafeArea(
        child: Container(
          decoration: const BoxDecoration(
            image: DecorationImage(
                image: AssetImage('assets/day.png'),
                fit: BoxFit.fill,
            ),
          ),
          child: Padding(
            padding: const EdgeInsets.fromLTRB(0.0,120.0,0.0,0.0),
            child: Column(
              children: [
                TextButton.icon(
                  onPressed: () async {
                    dynamic result = await Navigator.of(context).pushNamed('/location'); // Corrected route name
                    setState(() {
                      data = {
                        'time': result['time'],
                        'location': result['location'],
                        'isDayTime': result['isDayTime'], 
                        'flag': result['flag'], 
                      };
                    });
                  },
                  label: const Text('Choose Location',
                  style: TextStyle(color: Colors.white),),
                  icon: const Icon(
                      Icons.edit_location,
                      color: Colors.white,
                  ),
                ),
                  const SizedBox(height: 20.0),
                Row(
                  mainAxisAlignment: MainAxisAlignment.center,
                  children: [
                    Text(
                        data['location'],
                        style: const TextStyle(
                            fontSize:28.0,
                            letterSpacing:2.0,
                          color: Colors.white,
                    ),
                    )],
                ),
                const SizedBox(height: 20.0),
                Text(
                  data['time'],
                  style: const TextStyle(
                      fontSize: 66.0,
                    color: Colors.white,
                  ),
                )
              ],
            ),
          ),
        ),
      ),
    );
  }
}

pages/loading.dart

import 'package:flutter/material.dart';
import 'package:world_time/services/world_time.dart';
import 'package:flutter_spinkit/flutter_spinkit.dart';

class Loading extends StatefulWidget {
  @override
  State<Loading> createState() => _LoadingState();
}

class _LoadingState extends State<Loading> {
  String time = 'loading';
  bool isDaytime = true; // Initialize isDaytime as true or false

  Future<void> setupWorldTime() async {
    WorldTime instance = WorldTime(
      location: 'Berlin',
      flag: 'germany.png',
      time: time,
      url: 'Europe/Berlin',
      isDaytime: isDaytime, // Set isDaytime here
    );
    await instance.getTime();
    Navigator.pushReplacementNamed(context, '/home', arguments: {
      'location': instance.location,
      'flag': instance.flag,
      'time': instance.time,
      'isDaytime': instance.isDaytime,
    });
    print(instance.time);
    setState(() {
      time = instance.time;
    });
  }

  @override
  void initState() {
    super.initState();
    setupWorldTime();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.blue[900],
      body: const Center(
        child: SpinKitFadingCube(
          color: Colors.white,
          size: 50.0,
        ),
      ),
    );
  }
}

pages/choose_location

import 'package:flutter/material.dart';
import 'package:world_time/services/world_time.dart';

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

  @override
  State<ChooseLocation> createState() => _ChooseLocationState();
}

class _ChooseLocationState extends State<ChooseLocation> {
  List<WorldTime> locations = [
    WorldTime(location: 'London', flag: 'uk.png', url: 'Europe/London', time: '', isDaytime: true),
    WorldTime(location: 'Athens', flag: 'greece.png', url: 'Europe/Berlin', time: '', isDaytime: true),
    WorldTime(location: 'Cairo', flag: 'egypt.png', url: 'Africa/Cairo', time: '', isDaytime: true),
    WorldTime(location: 'Nairobi', flag: 'kenya.png', url: 'Africa/Nairobi', time: '', isDaytime: true),
    WorldTime(location: 'Chicago', flag: 'usa.png', url: 'America/Chicago', time: '', isDaytime: true),
    WorldTime(location: 'New York', flag: 'usa.png', url: 'America/New_York', time: '', isDaytime: true),
    WorldTime(location: 'Seoul', flag: 'south_korea.png', url: 'Asia/Seoul', time: '', isDaytime: true),
    WorldTime(location: 'Jakarta', flag: 'indonesia.png', url: 'Asia/Jakarta', time: '', isDaytime: true),
  ];

  void updateTime(index) async {
    WorldTime instance = locations[index];
    await instance.getTime();
    print(instance.location);
    // Navigate to the home screen
    // ignore: use_build_context_synchronously
    Navigator.pop(context, {
      'location': instance.location,
      'flag': instance.flag,
      'time': instance.time,
      'isDaytime': instance.isDaytime,
    });
  }

  @override
  Widget build(BuildContext context) {
    print('build function run');
    return Scaffold(
      backgroundColor: Colors.green,
      appBar: AppBar(
        backgroundColor: Colors.blue[900],
        title: const Text('Choose a Location'),
        centerTitle: true, // Center the title
        elevation: 0,
      ),
      body: ListView.builder(
        itemCount: locations.length,
        itemBuilder: (context, index) {
          return Padding(
            padding: const EdgeInsets.symmetric(vertical: 1.0, horizontal: 4.0),
            child: Card(
              child: ListTile(
                onTap: () {
                  updateTime(index);
                },
                title: Text(locations[index].location),
                leading: CircleAvatar(
                  backgroundImage: AssetImage('assets/${locations[index].flag}'),
                ),
              ),
            ),
          );
        },
      ),
    );
  }
}

this is my homepage homepage while i'm tapping going to choose location page chooselocation while i'm choosing the city it should update it on home page but throwing me some error like this enter image description here

Answer 1

In home.dart where you do setState you have

'isDayTime': result['isDayTime'], 

this needs to be

'isDaytime': result['isDaytime'], 

Notice the capital T that you have