【 Flutter 】Flutter を 基礎 から 学習 ( ウィジェット編 ) part49 Multi-child layout widgets

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

void main() {
  runApp(new MaterialApp(home: new MyApp()));
}

class MyApp extends StatefulWidget {
  @override
  State<StatefulWidget> createState() {
    return _State();
  }
}

class _State extends State<MyApp> {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('テスト中です。'),
        ),
        body: Stack(
          children: <Widget>[
            box(),
            box(
              color: const Color(0x44000000),
              alignment: const Alignment(0.2, 0.2),
            ),
            box(
                color: const Color(0x99FF0000),
                alignment: const Alignment(-0.2, -0.2)),
            // 子要素の位置を指定できます。
            Positioned(
              bottom: 300,
              right: 100,
              height: 200,
              child: new Text(
                "Flutterです!!",
                style: new TextStyle(
                  fontWeight: FontWeight.bold,
                  fontSize: 50.0,
                  color: Colors.pink[500],
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }

  Widget box({
    Color color = Colors.green,
    Alignment alignment = Alignment.center,
  }) {
    return Align(
        alignment: alignment,
        child: SizedBox(
            width: 100,
            height: 100,
            child: DecoratedBox(
              decoration: BoxDecoration(
                color: color,
              ),
            )));
  }
}