dropdown item from the list flutter

1String dropdownValue = 'One';
2
3@override
4Widget build(BuildContext context) {
5  return DropdownButton<String>(
6    value: dropdownValue,
7    icon: const Icon(Icons.arrow_downward),
8    iconSize: 24,
9    elevation: 16,
10    style: const TextStyle(
11      color: Colors.deepPurple
12    ),
13    underline: Container(
14      height: 2,
15      color: Colors.deepPurpleAccent,
16    ),
17    onChanged: (String? newValue) {
18      setState(() {
19        dropdownValue = newValue!;
20      });
21    },
22    items: <String>['One', 'Two', 'Free', 'Four']
23      .map<DropdownMenuItem<String>>((String value) {
24        return DropdownMenuItem<String>(
25          value: value,
26          child: Text(value),
27        );
28      })
29      .toList(),
30  );
31}

1  List<DropdownMenuItem<String>> getDropdownItems() {
2    List<DropdownMenuItem<String>> dropDownItems = [];
3
4    for (String currency in currenciesList) {
5      var newDropdown = DropdownMenuItem(
6        child: Text(currency),
7        value: currency,
8      );
9
10      dropDownItems.add(newDropdown);
11    }
12    return dropDownItems;
13  }