Flutter Tokyo Meetup #9 で発表したときのサンプルコード

rich_popup_screen.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'),
    );
  }
}

class MyHomePage extends StatelessWidget {
  final String title;

  const MyHomePage({this.title});

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text(title)),
      body: Center(
        child: RaisedButton(
          child: Text('リッチなポップアップ'),
          onPressed: () {
            _showRichPopup(context);
          },
        ),
      ),
    );
  }

  void _showRichPopup(BuildContext context) {
    showGeneralDialog(
        context: context,
        barrierLabel: 'Dismiss',
        barrierColor: Colors.black.withOpacity(0.5),
        barrierDismissible: false,
        transitionDuration: const Duration(milliseconds: 200),
        transitionBuilder: (_, animation, __, child) {
          return ScaleTransition(
            alignment: Alignment.center,
            scale: animation,
            child: child,
          );
        },
        pageBuilder: (context, _, __) {
          final size = MediaQuery.of(context).size;

          return Center(
            child: SizedBox(
              height: size.height * 0.7,
              width: size.width * 0.8,
              child: Card(
                elevation: 8,
                shape: RoundedRectangleBorder(
                  borderRadius: BorderRadius.all(
                    Radius.circular(12),
                  ),
                ),
                child: Column(
                  mainAxisAlignment: MainAxisAlignment.spaceEvenly,
                  children: <Widget>[
                    Icon(
                      Icons.image,
                      size: 200,
                    ),
                    Text(
                      'Rich Popup Screen 😁',
                      textAlign: TextAlign.center,
                      style: TextStyle(
                        color: Colors.black,
                        fontSize: 24,
                        fontWeight: FontWeight.bold,
                      ),
                    ),
                    Padding(
                      padding: const EdgeInsets.symmetric(horizontal: 24),
                      child: Text(
                        'Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. ',
                        textAlign: TextAlign.left,
                        maxLines: 5,
                        overflow: TextOverflow.ellipsis,
                        style: TextStyle(
                          color: Colors.grey,
                          fontSize: 18,
                        ),
                      ),
                    ),
                    FlatButton(
                      onPressed: () {
                        Navigator.pop(context);
                      },
                      color: Colors.blue,
                      shape: StadiumBorder(),
                      child: Text(
                        'OK',
                        style: TextStyle(color: Colors.white),
                      ),
                    )
                  ],
                ),
              ),
            ),
          );
        });
  }
}