# flutter/dart カリキュラム
###### tags: `curriculum` `seeds`

[TOC]

## 目標
- flutterの動きを一通り理解できるようになる
- flutterで簡単なアプリ(Todoアプリ)を作ってみる
- dockerの練習

## 成果物
- Todoアプリの制作

## 構成
### 環境構築
#### docker

- Dockerfile

FROM dart:2.17-sdk

# Workdir
WORKDIR /app

# 2: Install Flutter
ARG PATH=/root/.pub-cache/bin:$PATH
ARG FLUTTER_VERSION=3.0.1
RUN dart pub global activate melos --verbose && \
    dart pub global activate fvm --verbose && \
    fvm doctor --verbose && \
    fvm install $FLUTTER_VERSION --verbose && \
    fvm use --force $FLUTTER_VERSION --verbose && \
    fvm flutter config --enable-web --enable-linux-desktop --enable-macos-desktop --enable-windows-desktop --enable-android --enable-ios --enable-fuchsia && \
    # fvm flutter precache --verbose && \
    fvm flutter doctor --verbose

# Set paths
ENV FVM_ROOT=/root/.pub-cache
ENV PATH $FVM_ROOT/bin:$PATH

docker-compose.yml

version: "3.8"

services:
  flutter:
    container_name: flutter
    build: .
    volumes:
      - .:/app
    ports:
      - 3000:3000
    restart: always
    stdin_open: true
    tty: true

bash

#1行ずつ実行
docker compose build
docker compose up -d
docker exec -it flutter bash

#作成したコンテナにアクセス後
$ fvm use --force 3.0.1
$ fvm flutter create myapp
$ cd ./myapp
$ fvm flutter run -d web-server --web-port=5555
#localhost:5555にアクセスすると閲覧できる
$ exit

sudo chmod -R 777 ./todo/lib/main.dart

main.dart

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        // This is the theme of your application.
        //
        // Try running your application with "flutter run". You'll see the
        // application has a blue toolbar. Then, without quitting the app, try
        // changing the primarySwatch below to Colors.green and then invoke
        // "hot reload" (press "r" in the console where you ran "flutter run",
        // or simply save your changes to "hot reload" in a Flutter IDE).
        // Notice that the counter didn't reset back to zero; the application
        // is not restarted.
        primarySwatch: Colors.blue,
      ),
      home: const MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({Key? key, required this.title}) : super(key: key);

  // This widget is the home page of your application. It is stateful, meaning
  // that it has a State object (defined below) that contains fields that affect
  // how it looks.

  // This class is the configuration for the state. It holds the values (in this
  // case the title) provided by the parent (in this case the App widget) and
  // used by the build method of the State. Fields in a Widget subclass are
  // always marked "final".

  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;

  void _incrementCounter() {
    setState(() {
      // This call to setState tells the Flutter framework that something has
      // changed in this State, which causes it to rerun the build method below
      // so that the display can reflect the updated values. If we changed
      // _counter without calling setState(), then the build method would not be
      // called again, and so nothing would appear to happen.
      _counter++;
    });
  }

  @override
  Widget build(BuildContext context) {
    // This method is rerun every time setState is called, for instance as done
    // by the _incrementCounter method above.
    //
    // The Flutter framework has been optimized to make rerunning build methods
    // fast, so that you can just rebuild anything that needs updating rather
    // than having to individually change instances of widgets.
    return Scaffold(
      appBar: AppBar(
        // Here we take the value from the MyHomePage object that was created by
        // the App.build method, and use it to set our appbar title.
        title: Text(widget.title),
      ),
      body: Center(
        // Center is a layout widget. It takes a single child and positions it
        // in the middle of the parent.
        child: Column(
          // Column is also a layout widget. It takes a list of children and
          // arranges them vertically. By default, it sizes itself to fit its
          // children horizontally, and tries to be as tall as its parent.
          //
          // Invoke "debug painting" (press "p" in the console, choose the
          // "Toggle Debug Paint" action from the Flutter Inspector in Android
          // Studio, or the "Toggle Debug Paint" command in Visual Studio Code)
          // to see the wireframe for each widget.
          //
          // Column has various properties to control how it sizes itself and
          // how it positions its children. Here we use mainAxisAlignment to
          // center the children vertically; the main axis here is the vertical
          // axis because Columns are vertical (the cross axis would be
          // horizontal).
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            const Text(
              'You have pushed the button this many times:',
            ),
            Text(
              '$_counter',
              style: Theme.of(context).textTheme.headline4,
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: const Icon(Icons.add),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }
}

### 画面構築
#### リスト一覧画面

import 'package:flutter/material.dart';

void main() {
  // 最初に表示するWidget
  runApp(MyTodoApp());
}

class MyTodoApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      // アプリ名
      title: 'My Todo App',
      theme: ThemeData(
        // テーマカラー
        primarySwatch: Colors.blue,
      ),
      // リスト一覧画面を表示
      home: TodoListPage(),
    );
  }
}

// リスト一覧画面用Widget
class TodoListPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: Text('リスト一覧画面'),
      ),
    );
  }
}

#### リスト追加画面
main.dartに追加してみよう．

import 'package:flutter/material.dart';

// --- 省略 ---

// リスト一覧画面用Widget
class TodoListPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: Text('リスト一覧画面'),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () {
          // "push"で新規画面に遷移
          Navigator.of(context).push(
            MaterialPageRoute(builder: (context) {
              // 遷移先の画面としてリスト追加画面を指定
              return TodoAddPage();
            }),
          );
        },
        child: Icon(Icons.add),
      ),
    );
  }
}

// リスト追加画面用Widget
class TodoAddPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: TextButton(
          // ボタンをクリックした時の処理
          onPressed: () {
            // "pop"で前の画面に戻る
            Navigator.of(context).pop();
          },
          child: Text('リスト追加画面（クリックで戻る）'),
        ),
      ),
    );
  }
}