flutter控件之弹出菜单PopupmenuButton控件

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{
  String _bodyStr = "显示菜单内容";
  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: new AppBar(
        title: new Text("弹出菜单控件"),
        actions: [
          new PopupMenuButton(
            onSelected: (String value){
               setState(() {
                 _bodyStr = value;
               });
            },
              itemBuilder: (BuildContext context) =>>[
                new PopupMenuItem(
                    value:"选项一的内容",
                    child: new Text("选项一")
                ),
                new PopupMenuItem(
                  value: "选项二的内容",
                    child: new Text("选项二")
                )
              ]
          )
        ],
      ),
      body: new Center(
        child: new Text(_bodyStr),
      ),
    );
  }
}
void main(){
  runApp(new MaterialApp(
    title: "弹出菜单控件",
    theme: new ThemeData(primaryColor: Colors.deepOrange),
    home: new MenusDemo(),
  ));
}

 

效果：