在这种特殊情况下如何制作第二个子菜单？

Question

如何在 SubMenu1 下创建第二个子菜单？

像这样：

主菜单（点击并折叠）

____SubMenuItem1（点击并折叠）

__________SubMenuItem2

---

现在我只有主菜单和一个子菜单。 路线飞镖文件：

import 'file:///S:/AndroidStudioProjects/test_project/lib/menu.dart';
import 'package:font_awesome_flutter/font.dart';

import 'package:test_project/lib/SubMenu1.dart';


final List<dynamic> pages = [

  MenuItem(title: "info", icon: Icons.book, items: [
   SubMenuItem("SubMenu1", SubMenu1(),
        ),
  ]),

];

SubMenuItem getItemForKey(String key) {
  SubMenuItem item;
  List<dynamic> pag = List<dynamic>.from(pages);
  pag.forEach((page) {
    if (page is SubMenuItem && page.title == key) {
      item = page;
    } else if (page is MenuItem) {
      page.items.forEach((sub) {
        if (sub.title == key) item = sub;
      });
    }
  });
  return item;
}

和菜单页dart文件：

import 'package:flutter/material.dart';

class MenuItem {
  final String title;
  final List<SubMenuItem> items;
  final IconData icon;

  MenuItem(
      {Key key,
      @required this.title,
      this.items,
      this.icon = Icons.label_important});
}

class SubMenuItem {
  final String title;
  final Widget page;
  final IconData icon;
  final String path;

  SubMenuItem(this.title, this.page, {this.icon = Icons.block, this.path});
}

enum OpenMode { CODE, PREVIEW }

Answer 1

您的 SubMenuItem 类应该有一个 SubMenuItem 的递归列表。使用这种递归结构，您可以将子菜单项添加到您的子菜单项中。

class SubMenuItem {
  final String title;
  final Widget page;
  final IconData icon;
  final String path;
  final List<SubMenuItem> items;

  SubMenuItem(this.title, this.page, {this.icon = Icons.block, this.path, this.items});
}

实际上，在 MenuItem 类中定义它更适合您。有了它，您将不需要任何 SubMenuItem 类。

class MenuItem {
  final String title;
  final List<MenuItem> items; // Here is the recursive structure!
  final IconData icon;

  MenuItem(
      {Key key,
      @required this.title,
      this.items,
      this.icon = Icons.label_important});
}

Answer 2

根据需要使用扩展标题 main mneu=> submenu1=>submenu11。 此代码将对您有所帮助。

ExpansionTile(
                  title: Text("MAin Menu"),
                  children: [
                    ExpansionTile(
                      children: [
                        Text("Sub Menu 1"),
                      ],
                      title: Text("Sub Menu 1"),
                    )
                  ],
                ),