Flutter进阶—质感设计之弹出菜单

PopupMenuButton控件即弹出菜单控件，点击控件会出现菜单。

import 'package:flutter/material.dart';class MenusDemo extends StatefulWidget {  @override  _MenusDemoState createState() => new _MenusDemoState();}class _MenusDemoState extends State<MenusDemo> {  String _bodyStr = '显示菜单的点击';  @override  Widget build(BuildContext context) {    return new Scaffold(      appBar: new AppBar(        title: new Text('菜单演示'),        actions: <Widget> [          new PopupMenuButton<String>(            onSelected: (String value) {              setState(() {                _bodyStr = value;              });            },            itemBuilder: (BuildContext context) => <PopupMenuItem<String>>[              new PopupMenuItem<String>(                value: '选项一的值',                child: new Text('选项一')              ),              new PopupMenuItem<String>(                value: '选项二的值',                child: new Text('选项二')              )            ]          )        ]      ),      body: new Center(        child: new Text(_bodyStr)      )    );  }}void main() {  runApp(new MaterialApp(    title: 'Flutter教程',    home: new MenusDemo(),  ));}