Remove User Defined Item from List - list

Question

Hi I wanted to remove the Data from my List during onTap but I am unable to do so.
This is the code:
Widget buildUser(BuildContext context, AsyncSnapshot<QuerySnapshot> snapshot){
return ListView.builder(
itemCount: snapshot.data.documents.length,
itemBuilder: (context, index){
DocumentSnapshot user = snapshot.data.documents[index];
final style = _selectedBusStop.contains(ListClass(user.data['BusstopName'], user.data['location'].latitude.toString(), user.data['location'].longitude.toString()))
? TextStyle(
fontSize: 18,
color: Colors.blueAccent,
fontWeight: FontWeight.bold,
): TextStyle(fontSize: 18);
return ListTile(
leading: CircleAvatar(
backgroundImage: NetworkImage(
user.data['image']
),
),
title: Text(user.data['BusstopName'], style: style),
subtitle: Text('Operating Hour: ' + user.data['OperatingHour'], style: style),
trailing:
_selectedBusStop.contains((ListClass(user.data['BusstopName'], user.data['location'].latitude.toString(), user.data['location'].longitude.toString()))) ? Icon(Icons.check, color: Colors.blueAccent, size: 26) : null,
onTap: (){
if(_selectedBusStop.contains(ListClass(user.data['BusstopName'], user.data['location'].latitude.toString(), user.data['location'].longitude.toString()))){
setState(() {
_selectedBusStop.removeWhere((val) => val == ListClass(user.data['BusstopName'], user.data['location'].latitude.toString(), user.data['location'].longitude.toString()));
print (_selectedBusStop);
});
}
},
onLongPress: (){
setState(() {
_selectedBusStop.add(ListClass(user.data['BusstopName'], user.data['location'].latitude.toString(), user.data['location'].longitude.toString()));
print(_selectedBusStop);
});
}
);
},
);
}
This is the Class:
class ListClass{
String Bname;
String Blat;
String Blng;
ListClass(this.Bname, this.Blat, this.Blng);
#override
String toString(){
return '{${this.Bname}, ${this.Blat}, ${this.Blng}}';
}
}
Any idea where went wrong? Thank you in advance.
Update
List _selectedBusStop = [];
_selectedBusStop is empty List and upon LongPress it will add data into the List and upon onPress it will remove the data if the data already exist in the List.

Answer 1

#randomstudent the issue is the instance, when you comaparing two values with different instance but even value is same, it returns false,
for example to understand simply.
void main() {
final a = IntTestWrapper(3);
final b = IntTestWrapper(3);
print(a==b);
}
class IntTestWrapper {
IntTestWrapper(this.a);
final int a;
}
Output: false
If you want to compare, compare using equatable
if you change like this
class IntTestWrapper extends Equatable {
IntTestWrapper(this.a);
final int a;
#override
List<Object> get props => [a];
}
then for this
void main() {
final a = IntTestWrapper(3);
final b = IntTestWrapper(3);
print(a==b);
}
Output will be true.
To print you can override toString
void main() {
final a = IntTestWrapper(3);
final b = IntTestWrapper(3);
print(a);
}
class IntTestWrapper extends Equatable {
IntTestWrapper(this.a);
final int a;
#override
List<Object> get props => [a];
#override
String toString() => 'The value of a is :$a';
}
Output: The value of a is :3