I'm following along on a flutter "World Clock" project, As I'm new to the flutter eco system i occasionally encounter errors.
Here's the way the logic is set up across the project.
The "Home" page pulls data from a "Loading" page that initializes the "Home Screen" with an instance of a object using the "Navigator.pushReplacementNamed" command.
I want to be able to create other instances of objects using a listbuilder on a "Choose" page using the "Navigator.pop" command. Unfortunately i get the error
*"Undefined name 'context'. (Documentation)Try correcting the name to one that is defined, or defining the name." *
Here's my code.
Choose Page -
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();
}
List<WorldTime> locations = [
WorldTime('Lagos', 'time', 'nigeria.png', 'Africa/Lagos', true),
WorldTime('Islamabad', 'time', 'pakistan.png', 'Asia/Islamabad', true),
WorldTime('Lund', 'time', 'sweden.png', 'Europe/Lund', true),
WorldTime('Birmingham', 'time', 'uk.png', 'Europe/Birmingham', true),
WorldTime('London', 'time', 'uk.png' , 'Europe/London', true),
WorldTime('Athens', 'time', 'greece.png', 'Europe/Berlin', true),
WorldTime('Cairo', 'time', 'egypt.png', 'Africa/Cairo', true),
WorldTime('Nairobi', 'time', 'kenya.png', 'Africa/Nairobi', true),
WorldTime('Chicago', 'time', 'usa.png', 'America/Chicago', true),
WorldTime('New York', 'time', 'usa.png', 'America/New_York', true),
WorldTime('Seoul', 'time', 'south_korea.png', 'Asia/Seoul', true),
WorldTime('Jakarta', 'time', 'indonesia.png', 'Asia/Jakarta', true),
];
void updateTime(index) async {
WorldTime instance = locations[index];
await instance.getTime();
**//The error is on the next line of code - (Undefined name 'context')**
Navigator.pop(context, {
'location': instance.location,
'flag': instance.flag,
'time': instance.time,
'isDayTime': instance.isDayTime});
}
class _ChooseLocationState extends State<ChooseLocation> {
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
backgroundColor: Colors.blue[800],
title: const Text('Choose A Location'),
centerTitle: true,
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/${locations[index].flag}'),
),
),
),
);
}
),
);
}
}
Loading Page -
import 'package:flutter/material.dart';
import 'package:world_time/services/world_time.dart';
import 'package:flutter_spinkit/flutter_spinkit.dart';
class Loading extends StatefulWidget {
const Loading({Key? key}) : super(key: key);
@override
State<Loading> createState() => _LoadingState();
}
class _LoadingState extends State<Loading> {
void setupWorldTime() async {
WorldTime instance = WorldTime('Berlin', 'time', 'germany.png', 'Europe/Berlin', true);
await instance.getTime();
Navigator.pushReplacementNamed(context,'/home', arguments: {
'location': instance.location,
'flag': instance.flag,
'time': instance.time,
'isDayTime': instance.isDayTime
});
}
@override
void initState(){
super.initState();
setupWorldTime();
}
@override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: Colors.lightBlue,
body:Center(
child: SpinKitFadingCircle(
itemBuilder: (BuildContext context, int index) {
return DecoratedBox(
decoration: BoxDecoration(
color: index.isEven ? Colors.white : Colors.lightBlue,
),
);
},
),
),
);
}
}
Home Page -
class Home extends StatefulWidget {
const Home({Key? key}) : super(key: key);
@override
State<Home> createState() => _HomeState();
}
class _HomeState extends State<Home> {
Map data = {};
@override
Widget build(BuildContext context) {
data = data.isNotEmpty ? data : ModalRoute.of(context)?.settings.arguments as Map<dynamic,dynamic>;
print(data);
String bgImage = (data?['isDayTime'] ?? false) ?'day.png' : 'night.png';
Color bgColor = (data?['isDayTime'] ?? false) ? Colors.lightBlue : Colors.blue;
return Scaffold(
backgroundColor: bgColor,
body: Container(
decoration: BoxDecoration(
image: DecorationImage(
image: AssetImage('assets/$bgImage'),
fit:BoxFit.cover,
),
),
child: Padding(
padding: const EdgeInsets.fromLTRB(0,120,0,0),
child: SafeArea(
child: Column(
children: [
TextButton.icon(onPressed: ()async {
dynamic result = await Navigator.pushNamed(context, '/location');
setState(() {
data = {
'time': result['time'],
'location': result['location'],
'isDayTime': result['isDayTime'],
'flag': result['flag']
};
});
}, icon: const Icon(Icons.edit_location), label: const Text('Edit Location'),
style: TextButton.styleFrom(
foregroundColor: Colors.grey[300],
),
),
SizedBox(height: 20.0),
Row(
mainAxisAlignment: MainAxisAlignment.center,
children: [
Text(data['location'],
style: TextStyle(fontSize: 28, letterSpacing: 2, color: Colors.white),
),
],
),
SizedBox(height: 20),
Text(data['time'],
style: TextStyle(fontSize: 66, color: Colors.white),
),
],
),
),
),
),
);
}
}
I've tried ways to instantiate context but i'm not sure what data structure would work
