写一个flutter Android TV 示例,如何获取一个列表中当前遥控器按键所在列表子项位置的焦点,并对遥控器焦点所在的位置进行遥控器按键确认键的处理(带注释)

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Android TV Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: MyHomePage(),
);
}
}

class MyHomePage extends StatefulWidget {
@override
_MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
// 定义一个列表
List<String> _list = [
'Item 1',
'Item 2',
'Item 3',
'Item 4',
'Item 5',
];

// 定义一个变量，用于记录当前焦点所在位置
int _currentPosition = 0;

// 处理遥控器键盘事件
void _handleKeyEvent(RawKeyEvent event) {
// 判断事件类型是否为按键按下事件
if (event.runtimeType == RawKeyDownEvent) {
// 获取按下的按键值
RawKeyEventDataAndroid data = event.data as RawKeyEventDataAndroid;
int keyCode = data.keyCode;

// 根据按键值处理不同的逻辑
switch (keyCode) {
case 19: // 上键
if (_currentPosition > 0) {
setState(() {
_currentPosition--;
});
}
break;
case 20: // 下键
if (_currentPosition < _list.length - 1) {
setState(() {
_currentPosition++;
});
}
break;
case 23: // 确认键
// 处理确认键的逻辑
// 这里只是简单的弹出一个对话框
showDialog(
context: context,
builder: (BuildContext context) {
return AlertDialog(
title: Text('Confirm'),
content: Text('You selected ${_list[_currentPosition]}'),
actions: <Widget>[
FlatButton(
child: Text('OK'),
onPressed: () {
Navigator.of(context).pop();
},
),
],
);
},
);
break;
}
}
}

@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Flutter Android TV Demo'),
),
body: RawKeyboardListener(
focusNode: FocusNode(),
onKey: _handleKeyEvent,
child: ListView.builder(
itemCount: _list.length,
itemBuilder: (BuildContext context, int index) {
return Container(
height: 50.0,
color: _currentPosition == index ? Colors.blueAccent : Colors.white,
child: Center(
child: Text(
_list[index],
style: TextStyle(
fontSize: 20.0,
fontWeight: FontWeight.bold,
),
),
),
);
},
),
),
);
}
}