Flutter Errors: Undefined name "context" - flutter

Question

I receive some errors when I try to push my flutter page from neighbourhoodList to individual neighbourhoods (e.g. neighbourhoodlist_admirality).
In my neighbourhoodlist, I would like to navigate to the individual neighbourhood pages when the user has clicked on the relevant neighbourhood. As I have not build the individual neighbourhood pages yet, I have linked them to an example page i.e. NeighbourhoodAdmirality.
This is my code for the neighbourhoodlist page:
import 'package:flutter/material.dart';
import 'indv_neighbourhoods/neighbourhoodlist_admirality.dart';
class NeighbourhoodList extends StatefulWidget {
NeighbourhoodList({ this.name = "name"});
final String name;
#override
_NeighbourhoodListState createState() => _NeighbourhoodListState();
}
class _NeighbourhoodListState extends State<NeighbourhoodList> {
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(
'Neighbourhoods',
),
),
body: _buildListView(context),
);
}
ListView _buildListView(BuildContext context){
return ListView.builder(
itemCount: allNeighbourhoods.length,
itemBuilder: (BuildContext content, int index) {
NeighbourhoodList neighbourhoodlist = allNeighbourhoods[index];
return NeighbourhoodListTile(neighbourhoodlist);
});
}
}
class NeighbourhoodListTile extends ListTile {
NeighbourhoodListTile(NeighbourhoodList neighbourhoodlist)
: super(
title: Text(neighbourhoodlist.name),
trailing: Icon(Icons.arrow_forward),
onTap: (){
Navigator.push(
context,
MaterialPageRoute(builder: (context) => NeighbourhoodAdmiralty(neigh1)),
);
}
);
}
List<NeighbourhoodList> allNeighbourhoods = [
NeighbourhoodList(name: 'Admiralty'),
NeighbourhoodList(name: 'Aljunied'),
NeighbourhoodList(name: 'Ang Mo Kio'),
];
This is my code for an example page that I want to direct my neighbourhoodlist to when each individual neighbourhood is directed.
import 'package:flutter/material.dart';
class NeighbourhoodAdmiralty extends StatefulWidget {
final String neigh1;
NeighbourhoodAdmiralty(this.neigh1);
#override
_NeighbourhoodAdmiraltyState createState() => _NeighbourhoodAdmiraltyState();
}
class _NeighbourhoodAdmiraltyState extends State<NeighbourhoodAdmiralty> {
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("Admiralty"),
),
body: Center(child: Text('This is the individual neighbourhood page'),
),
);
}
}
As I am still a beginner, I am facing some errors and have a few questions on these:
Error 1 on neighbourhoodlist.dart: "Undefined name 'context'" under Navigator.push --> not sure why this happens as I have already passed the BuildContext in my methods above
Error 2 on neighbourhoodlist.dart: "Undefined name 'neigh1'" under Navigator.push --> I would like to redirect the neighbourhoodlist.dart page to the individual neighbourhood sheets but I'm not sure what I pass here, I have tried 'neigh1' (my variable in neighbourhoodlist_admirality), 'name' - the variable in NeighbourhoodList, and 'index' 0 the variable inNeighbourhoodListState but none of them seem to work so far.
Appreciate all your help in resolving this and thanks in advance !

Answer 1

When you do
class NeighbourhoodListTile extends ListTile {
NeighbourhoodListTile(NeighbourhoodList neighbourhoodlist)
: super(
title: Text(neighbourhoodlist.name),
trailing: Icon(Icons.arrow_forward),
onTap: (){
Navigator.push(context, MaterialPageRoute(builder: (context) => NeighbourhoodAdmiralty(neigh1)));
}
);
}
you can't access context in onTap because Flutter hasn't yet provided one to you in this point. If you need the context, use a StatelessWidget instead, where you can access it in the build method:
class NeighbourhoodListTile extends StatelessWidget {
final NeighbourhoodList neighbourhoodlist;
const NeighbourhoodListTile(this.neighbourhoodlist);
#override
Widget build(BuildContext context) {
// Here's your context ^^^^^^^
return ListTile(
title: Text(neighbourhoodlist.name),
trailing: Icon(Icons.arrow_forward),
onTap: (){
Navigator.push(context, MaterialPageRoute(
builder: (context) => NeighbourhoodAdmiralty(neigh1)));
}
);
}
}
As to your second error, there is also no neigh1 variable at this point. I don't know what your logic is, but I think you want to replace it with neighbourhoodlist.name:
class NeighbourhoodListTile extends StatelessWidget {
final NeighbourhoodList neighbourhoodlist;
const NeighbourhoodListTile(this.neighbourhoodlist);
#override
Widget build(BuildContext context) {
return ListTile(
title: Text(neighbourhoodlist.name),
trailing: Icon(Icons.arrow_forward),
onTap: (){
Navigator.push(context, MaterialPageRoute(
builder: (context) => NeighbourhoodAdmiralty(neighbourhoodlist.name)));
}
);
}
}