how to create a drop down list in flutter code example

Example 1: dropdown button flutter example

DropdownButton<String>(
                value: 'Dept1',
                elevation: 16,
                icon: Icon(Icons.arrow_drop_down_circle),
                isExpanded: true,
                items: <String>['Dept1','Dept2'].map((e) {
                  return DropdownMenuItem(
                    value: e,
                    child: Text(e) ,
                  );
                }).toList(),
              onChanged: (value){},
              ),

Example 2: how to create drop down list in flutter

new DropdownButton<String>(
  items: <String>['A', 'B', 'C', 'D'].map((String value) {
    return new DropdownMenuItem<String>(
      value: value,
      child: new Text(value),
    );
  }).toList(),
  onChanged: (_) {},
)