模态底部面板是菜单或对话框的替代方案，可防止用户与其他控件进行互动，可以使用showModalBottomSheet函数创建和显示模态底部面板。

import 'package:flutter/material.dart';

class MyApp extends StatelessWidget {

 @override
 Widget build(BuildContext context) {
  return new Scaffold(
   appBar: new AppBar(
    title: new Text('底部面板')
   ),
   body: new Center(
    child: new RaisedButton(
     child: new Text('显示底部面板'),
     onPressed: () {
      // showModalBottomSheet：显示模态质感设计底部面板
      showModalBottomSheet(context:context, builder:(BuildContext context) {
       return new Container(
        child: new Padding(
         padding: const EdgeInsets.all(32.0),
         child: new Text(
          '这是模态底部面板，点击任意位置即可关闭',
          textAlign: TextAlign.center,
          style: new TextStyle(
           color: Theme.of(context).accentColor,
           fontSize: 24.0
          )
         )
        )
       );
      });
     }
    )
   )
  );
 }
}

void main() {
 runApp(new MaterialApp(
  title: 'Flutter Demo',
  home: new MyApp()
 ));
}