Flutter: How to get the baseurl from the societies? - flutter

Question

for an authentication I would like to recover the base_url of the company chosen from a drop-down list, but I can't do it, being a beginner a little help will be welcome.
here is the code of the dropdownlist:
class DropDown extends StatefulWidget {
DropDown({Key key}) : super(key: key);
#override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<DropDown> {
String _mySelection;
String _myBaseUrl;
List<Map> _myJson = [{"id":2,"society":"test","baseUrl":"url.com"},{"id":1,"society":"planeef","baseUrl":"url.com"}];
#override
Widget build(BuildContext context) {
return Container(
child: new DropdownButton<String>(
isDense: true,
hint: new Text("Select"),
value: _mySelection,
onChanged: (String newValue) {
setState(() {
_mySelection = newValue;
});
},
items: _myJson.map((Map map) {
return new DropdownMenuItem<String>(
value: map["id"].toString(),
child: new Text(
map["society"],
),
);
}).toList(),
),
);
}
}

Answer 1

Check the code below. You can use singleWhere function to retrieve the element from the id value you are getting from the dropdown and then read baseUrl from the element.
The singleWhere function matches and returns a single element from the list based on the condition we provide.
Note -
The singleWhere function throws an error by default if there are duplicates or no element is found. You might need to also pass the orElse parameter to singleWhere or add some error handling in that case.
More about that can be found here.
class _MyHomePageState extends State<MyHomePage> {
String _mySelection;
List<Map> _myJson = [{"id":2,"society":"test","baseUrl":"url.com"},{"id":1,"society":"planeef","baseUrl":"url.com"}];
#override
Widget build(BuildContext context) {
return Scaffold(
body: Container(
child: new DropdownButton<String>(
isDense: true,
hint: new Text("Select"),
value: _mySelection,
onChanged: (String newValue) {
Map<dynamic,dynamic> _myElement = _myJson.singleWhere((test) => test["id"] == int.parse(newValue));
print(_myElement["baseUrl"]);
//Add the above two lines
setState(() {
_mySelection = newValue;
});
},
items: _myJson.map((Map map) {
return new DropdownMenuItem<String>(
value: map["id"].toString(),
child: new Text(
map["society"],
),
);
}).toList(),
),
)
);
}
}