在Dart/Flutter中编码需要我的第一个磁贴只出现一次

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('Unique Tile Example'),
        ),
        body: Center(
          child: TileWidget(),
        ),
      ),
    );
  }
}

class TileWidget extends StatefulWidget {
  @override
  _TileWidgetState createState() => _TileWidgetState();
}

class _TileWidgetState extends State<TileWidget> {
  bool isFirstTileVisible = true;

  @override
  Widget build(BuildContext context) {
    return Column(
      mainAxisAlignment: MainAxisAlignment.center,
      children: [
        if (isFirstTileVisible)
          Tile(key: UniqueKey()),
        RaisedButton(
          child: Text('Toggle First Tile'),
          onPressed: () {
            setState(() {
              isFirstTileVisible = !isFirstTileVisible;
            });
          },
        ),
      ],
    );
  }
}

class Tile extends StatelessWidget {
  Tile({Key key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Container(
      width: 200,
      height: 200,
      color: Colors.blue,
      child: Center(
        child: Text(
          'First Tile',
          style: TextStyle(
            fontSize: 24,
            color: Colors.white,
          ),
        ),
      ),
    );
  }
}