Flutter dropdown items not showing - flutter

Question

I am showing i simple drop down but my options are not opening mean its not showing a dropdown.
I have a simple list like this
[352094083791878, 358480083322091, 358480081409924]
This is my code
class _SettingPageState extends State<SettingPage> {
bool isSwitched = false;
bool _shoW = true;
var items = [];
#override
void initState() {
super.initState();
getImi();
}
getImi() async {
final storage = new FlutterSecureStorage();
String userNumber = await storage.read(key: "userNumber");
String userPassword = await storage.read(key: "userPassword");
print('showimi');
print(userNumber);
print(userPassword);
var map = new Map<String, dynamic>();
showDialog(
context: context,
barrierDismissible: false,
builder: (BuildContext context) {
return Center(
child: SpinKitWave(
color: Color(0xff00abb5), type: SpinKitWaveType.center));
});
var url =
'http://api.igiinsurance.com.pk:8888/drive_api/login.php?number=${userNumber}&password=${userPassword}';
print(url);
http.Response res = await http.get(
url,
headers: <String, String>{'token': 'c66026133e80d4960f0a5b7d418a4d08'},
);
var data = json.decode(res.body.toString());
print(data);
if (data['status'].toString() == "Success") {
Navigator.pop(context);
_shoW = true;
data['data'].forEach((row) {
print(row['imei_number']);
items.add(row['imei_number']);
print(items);
});
} else {
Navigator.pop(context);
_shoW = false;
}
}
#override
Widget build(BuildContext context) {
double width = MediaQuery.of(context).size.width;
double height = MediaQuery.of(context).size.height;
return Scaffold(
body: DecoratedBox(
decoration: BoxDecoration(
image: DecorationImage(
image: AssetImage("images/sidebg.png"), fit: BoxFit.cover),
),
child: Column(
children: [
_shoW
? DropdownButton(
hint: Text('Select Vechile'),
items: items.map((val) {
return DropdownMenuItem<String>(
value: val,
child: new Text(val),
);
}).toList(),
onChanged: null)
: Container()
],
),
),
);
}
}
I am simply adding values in the Items array. I need to show the array in the select down list. But it's not opening the options i have try to put static list but that's also not working .

Answer 1

You need to set onChanged to not null value. onChanged without listener cannot allow you to open list.
If you need to showing current selected value, pass value parameter to DropdownButton. Also you can find more examples in Official Flutter Documentation.

Answer 2

Change Your Code Like THis :
if (data['status'].toString() == "Success") {
Navigator.pop(context);
setState(){
_shoW = true;
}
data['data'].forEach((row) {
print(row['imei_number']);
items.add(row['imei_number']);
print(items);
});
} else {
Navigator.pop(context);
setState(){
_shoW = false;
}
}