【 Flutter 】Flutter を 基礎 から 学習 ( ウィジェット編 ) part08 基本的なウィジェット

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

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      // home: MyHomePage(title: 'Flutter Demo Home Page'),
      initialRoute: '/',
      routes: {
        '/': (context) => FirstPage(),
      },
    );
  }
}

class FirstPage extends StatelessWidget {
  Widget build(BuildContext context) {
    final ThemeData theme = Theme.of(context);
    final TextTheme textTheme = theme.textTheme;
    final titleStyle =
        textTheme.headline6!.copyWith(color: theme.backgroundColor);

    return Scaffold(
      appBar: AppBar(
          title: Text(
        'First Page',
        style: titleStyle,
      )),
      body: Column(
        mainAxisAlignment: MainAxisAlignment.spaceAround,
        children: <Widget>[
          DefaultTextStyle(
            style: Theme.of(context)
                .textTheme
                .headline6!, // !を付けないとコンパイルエラーとなります・・・。

            child: Row(
              mainAxisAlignment: MainAxisAlignment.spaceAround,
              children: <Widget>[Text('A'), Text('B'), Text('C')],
            ),
          ),
          // 比較用になにもスタイルを適用していないウィジェットを設置します
          Row(
            mainAxisAlignment: MainAxisAlignment.spaceAround,
            children: <Widget>[Text('D'), Text('E'), Text('F')],
          ),
        ],
      ),
    );
  }
}