动画可移动列表在颤动

Question

有什么提示或帮助吗？我如何在flutter中制作这个点击可移动列表？

https://files.fm/f/txdn29dg3

Answer 1

所提供的组件正是CupertinoPicker可以为您提供的。

此外，正如文档中所建议的，您应该将CupertinoPicker和showCupertinoModalPopup组合起来，以便在屏幕底部以模式显示选择器。

这就是代码的样子：

void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
theme: ThemeData.dark().copyWith(
scaffoldBackgroundColor: darkBlue,
),
debugShowCheckedModeBanner: false,
home: const Scaffold(
body: Center(
child: PickerPage(),
),
),
);
}
}
class PickerPage extends StatefulWidget {
const PickerPage();
@override
_PickerPageState createState() => _PickerPageState();
}
class _PickerPageState extends State<PickerPage> {
final _items = [
'Flat Rate',
'Hourly',
'Request for Price',
];
int _selectedItem = 0;
void _onSelectedItemChanged(int value) => setState(
() => _selectedItem = value,
);
void _showPicker() {
showCupertinoModalPopup(
context: context,
builder: (_) => PickerExample(
items: _items,
selectedItem: _selectedItem,
onSelectedItemChanged: _onSelectedItemChanged,
),
);
}
@override
Widget build(BuildContext context) {
return Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
Text(_items[_selectedItem]),
const SizedBox(height: 10.0),
ElevatedButton(
child: const Text('Show picker'),
onPressed: _showPicker,
),
],
);
}
}
class PickerExample extends StatefulWidget {
final List<String> items;
final int selectedItem;
final ValueSetter<int> onSelectedItemChanged;
const PickerExample({
required this.items,
required this.selectedItem,
required this.onSelectedItemChanged,
});
@override
_PickerExampleState createState() => _PickerExampleState();
}
class _PickerExampleState extends State<PickerExample> {
late final FixedExtentScrollController _controller;
@override
void initState() {
super.initState();
_controller = FixedExtentScrollController(initialItem: widget.selectedItem);
}
@override
void dispose() {
_controller.dispose();
super.dispose();
}
@override
Widget build(BuildContext context) {
return SizedBox(
height: 300,
child: CupertinoPicker(
scrollController: _controller,
backgroundColor: Colors.white,
itemExtent: 30.0,
children: [
for (final item in widget.items) Center(child: Text(item)),
],
onSelectedItemChanged: widget.onSelectedItemChanged,
),
);
}
}

您也可以在这个DartPad中找到一个交互式示例。