【 Flutter 】Flutter を 基礎 から 学習 ( ウィジェット編 ) part56 Multi-child layout widgets

基礎 から 学ぶ Flutter 」という書籍で  学習 したことを ブログでアウトプットしていこうと思います。今回は ウィジェット編 ( part56 )です。

前回

【 Flutter 】Flutter を 基礎 から 学習 ( ウィジェット編 ) part55 Multi-child layout widgets

引き続き、Multi-child layout widgetsについて学びます。

Multi-child layout widgets

Wrapウィジェット

alignmentプロパティ

alignmentプロパティは「配置方法」を指定するプロパティでしょうか。
何も指定していない場合はWrapAlignment.starを指定するのと同義です。

WrapAlignment.end
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: Container(
            child: Wrap(
          alignment: WrapAlignment.end,
          children: <Widget>[
            box(txt: "1"),
            box(txt: "2"),
            box(txt: "3"),
            box(txt: "4"),
            box(txt: "5")
          ],
        )),
      ),
    );
  }

  Widget box(
      {double size = 120,
      Color color = Colors.green,
      Alignment alignment = Alignment.center,
      String txt = "0"}) {
    return Container(
        margin: const EdgeInsets.all(8),
        alignment: alignment,
        width: size,
        height: size,
        color: color,
        child: Text(txt));
  }
}

WrapAlignment.center
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: Container(
            child: Wrap(
          alignment: WrapAlignment.center,
          children: <Widget>[
            box(txt: "1"),
            box(txt: "2"),
            box(txt: "3"),
            box(txt: "4"),
            box(txt: "5")
          ],
        )),
      ),
    );
  }

  Widget box(
      {double size = 120,
      Color color = Colors.green,
      Alignment alignment = Alignment.center,
      String txt = "0"}) {
    return Container(
        margin: const EdgeInsets.all(8),
        alignment: alignment,
        width: size,
        height: size,
        color: color,
        child: Text(txt));
  }
}

WrapAlignment.spaceEvenly
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: Container(
            child: Wrap(
          alignment: WrapAlignment.spaceEvenly,
          children: <Widget>[
            box(txt: "1"),
            box(txt: "2"),
            box(txt: "3"),
            box(txt: "4"),
            box(txt: "5")
          ],
        )),
      ),
    );
  }

  Widget box(
      {double size = 120,
      Color color = Colors.green,
      Alignment alignment = Alignment.center,
      String txt = "0"}) {
    return Container(
        margin: const EdgeInsets.all(8),
        alignment: alignment,
        width: size,
        height: size,
        color: color,
        child: Text(txt));
  }
}

WrapAlignment.spaceBetween
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: Container(
            child: Wrap(
          alignment: WrapAlignment.spaceBetween,
          children: <Widget>[
            box(txt: "1"),
            box(txt: "2"),
            box(txt: "3"),
            box(txt: "4"),
            box(txt: "5")
          ],
        )),
      ),
    );
  }

  Widget box(
      {double size = 120,
      Color color = Colors.green,
      Alignment alignment = Alignment.center,
      String txt = "0"}) {
    return Container(
        margin: const EdgeInsets.all(8),
        alignment: alignment,
        width: size,
        height: size,
        color: color,
        child: Text(txt));
  }
}

WrapAlignment.spaceAround
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: Container(
            child: Wrap(
          alignment: WrapAlignment.spaceAround,
          children: <Widget>[
            box(txt: "1"),
            box(txt: "2"),
            box(txt: "3"),
            box(txt: "4"),
            box(txt: "5")
          ],
        )),
      ),
    );
  }

  Widget box(
      {double size = 120,
      Color color = Colors.green,
      Alignment alignment = Alignment.center,
      String txt = "0"}) {
    return Container(
        margin: const EdgeInsets.all(8),
        alignment: alignment,
        width: size,
        height: size,
        color: color,
        child: Text(txt));
  }
}

最後に

たくさん選択肢がありますね。

本書に掲載されている図では上手に違いを表現できていましたが私の場合はウィジェットの大きさのせいなのか違いは今一つわかりませんでした😑

今日はここまで!