1.簡介
Dropdown button 用于從項(xiàng)目列表中選擇的按鈕
- 參數(shù)類型T時(shí)下拉菜單表示的值的類型答捕。給定菜單中的所有條目必須具有一致的類型焰轻。
2.示例代碼
class DropdownButtonDefault extends StatefulWidget {
@override
State<StatefulWidget> createState() => _DropdownButtonDefault();
}
class _DropdownButtonDefault extends State{
var selectValue;
var selectItemValue = '暫無';
List<DropdownMenuItem>generateItemList() {
final List<DropdownMenuItem>items = List();
final DropdownMenuItem item1 = DropdownMenuItem(
value: '張三',
child: Text('張三'),
);
final DropdownMenuItem item2 = DropdownMenuItem(
value: '李四',
child: Text('李四'),
);
final DropdownMenuItem item3 = DropdownMenuItem(
value: '王二',
child: Text('王二'),
);
final DropdownMenuItem item4 = DropdownMenuItem(
value: '麻子',
child: Text('麻子'),
);
items.add(item1);
items.add(item2);
items.add(item3);
items.add(item4);
return items;
}
@override
Widget build(BuildContext context) {
return DropdownButton(
hint: Text('$selectItemValue'),
value: selectValue,
items: generateItemList(),
onChanged: (T){
setState((){
selectItemValue = T;
});
},
);
}
}
