フィルタ付き選択ダイアログ

main.dart

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

void main() => runApp(MaterialApp(
  home: Scaffold(
    appBar: AppBar(
      title: const Text("フィルタ付き選択ダイアログ"),
    ),
    body: ListView(
      children: const [SelectTile()],
    ),
  ),
));

typedef Prefecture = (String, {String hiragana, String roman});

class SelectTile extends HookWidget {
   const SelectTile();
  
  @override
  Widget build(BuildContext context) {
    final pref = useState<Prefecture?>(null);
    return ListTile(
      title: const Text("県"),
      subtitle: Text(pref.value?.$1 ?? "選択されていません"),
      onTap: () async {
        final selected = await PrefSelectDialog.show(context);
        if (selected != null) pref.value = selected;
      }
    );
  }
}

class PrefSelectDialog extends StatelessWidget {
  static Future<Prefecture?> show(BuildContext context) =>
    showDialog(context: context, builder: (_) => const PrefSelectDialog());
  
  const PrefSelectDialog();
  
  @override
  Widget build(BuildContext context) {
    return AlertDialog(
      title: const Text("県を選択"),
      content: PrefectureList(
        onTap: (pref) => Navigator.pop(context, pref),
      ),
      actions: <Widget>[
        TextButton(
          onPressed: () => Navigator.pop(context),
          child: const Text("キャンセル"),
        ),
      ],
    );
  }
}

class PrefectureList extends HookWidget {
  
  final void Function(Prefecture) onTap;
  
  const PrefectureList({required this.onTap});
  
  @override
  Widget build(BuildContext context) {
    final controller = useTextEditingController();
    useListenable(controller);
    return SizedBox(
      width: 420,
      height: 480,
      child: Column(
        children: [
          TextField(
            controller: controller,
            decoration: InputDecoration(
              prefixIcon: const Padding(
                padding: EdgeInsets.symmetric(horizontal: 16.0),
                child: Icon(Icons.search),
              ),
              contentPadding: const EdgeInsets.all(16),
              border:
                  OutlineInputBorder(borderRadius: BorderRadius.circular(24)),
            ),
          ),
          const SizedBox(height: 16),
          Expanded(
            child: ListView(
              scrollDirection: Axis.vertical,
              shrinkWrap: true,
              children: prefectures
                .where((pref) {
                  final (name, hiragana: hiragana, roman: roman) = pref;
                  final text = controller.text.toLowerCase();
                  return name.contains(text) || hiragana.contains(text) || roman.contains(text);
                })
                .map((pref) => ListTile(
                  title: Text(pref.$1),
                  onTap: () => onTap(pref),
                ))
                .toList()
            ),
          ),
        ],
      ),
    );
  }
}

const prefectures = <Prefecture>[
  ("北海道", hiragana: "ほっかいどう", roman: "hokkaido"),
  ("青森県", hiragana: "あおもり", roman: "aomori"),
  ("岩手県", hiragana: "いわて", roman: "iwate"),
  ("宮城県", hiragana: "みやぎ", roman: "miyagi"),
  ("秋田県", hiragana: "あきた", roman: "akita"),
  ("山形県", hiragana: "やまがた", roman: "yamagata"),
  ("福島県", hiragana: "ふくしま", roman: "fukushima"),
  ("茨城県", hiragana: "いばらき", roman: "ibaraki"),
  ("栃木県", hiragana: "とちぎ", roman: "tochigi"),
  ("群馬県", hiragana: "ぐんま", roman: "gunma"),
  ("埼玉県", hiragana: "さいたま", roman: "saitama"),
  ("千葉県", hiragana: "ちば", roman: "chiba"),
  ("東京都", hiragana: "とうきょう", roman: "tokyo"),
  ("神奈川県", hiragana: "かながわ", roman: "kanagawa"),
  ("新潟県", hiragana: "にいがた", roman: "niigata"),
  ("富山県", hiragana: "とやま", roman: "toyama"),
  ("石川県", hiragana: "いしかわ", roman: "ishikawa"),
  ("福井県", hiragana: "ふくい", roman: "fukui"),
  ("山梨県", hiragana: "やまなし", roman: "yamanashi"),
  ("長野県", hiragana: "ながの", roman: "nagano"),
  ("岐阜県", hiragana: "ぎふ", roman: "gifu"),
  ("静岡県", hiragana: "しずおか", roman: "shizuoka"),
  ("愛知県", hiragana: "あいち", roman: "aichi"),
  ("三重県", hiragana: "みえ", roman: "mie"),
  ("滋賀県", hiragana: "しが", roman: "shiga"),
  ("京都府", hiragana: "きょうと", roman: "kyoto"),
  ("大阪府", hiragana: "おおさか", roman: "osaka"),
  ("兵庫県", hiragana: "ひょうご", roman: "hyogo"),
  ("奈良県", hiragana: "なら", roman: "nara"),
  ("和歌山県", hiragana: "わかやま", roman: "wakayama"),
  ("鳥取県", hiragana: "とっとり", roman: "tottori"),
  ("島根県", hiragana: "しまね", roman: "shimane"),
  ("岡山県", hiragana: "おかやま", roman: "okayama"),
  ("広島県", hiragana: "ひろしま", roman: "hiroshima"),
  ("山口県", hiragana: "やまぐち", roman: "yamaguchi"),
  ("徳島県", hiragana: "とくしま", roman: "tokushima"),
  ("香川県", hiragana: "かがわ", roman: "kagawa"),
  ("愛媛県", hiragana: "えひめ", roman: "ehime"),
  ("高知県", hiragana: "こうち", roman: "kochi"),
  ("福岡県", hiragana: "ふくおか", roman: "fukuoka"),
  ("佐賀県", hiragana: "さが", roman: "saga"),
  ("長崎県", hiragana: "ながさき", roman: "nagasaki"),
  ("熊本県", hiragana: "くまもと", roman: "kumamoto"),
  ("大分県", hiragana: "おおいた", roman: "oita"),
  ("宮崎県", hiragana: "みやざき", roman: "miyazaki"),
  ("鹿児島県", hiragana: "かごしま", roman: "kagoshima"),
  ("沖縄県", hiragana: "おきなわ", roman: "okinawa"),
];