Animated Sidebar
A highly customizable and styleable collapsable sidebar plugin for Flutter, optimized for web and desktop applications.
Example

Installation
Add the following to your pubspec.yaml file:
dependencies:  
 animated_sidebar: ^1.0.0   
or use the following command:
flutter pub add animated_sidebar  
Add the following import to your dart file:
import 'package:animated_sidebar/animated_sidebar.dart';  
Usage
Sidebar Items
define a list of SidebarItem objects:
import 'package:animated_sidebar/animated_sidebar.dart';  
  
final List<SidebarItem> items = [  
  SidebarItem(icon: Icons.home, text: 'Home'),  
  SidebarItem(icon: Icons.notifications, text: 'Notifications'),  
  SidebarItem(icon: Icons.person, text: 'Management'),  
];  
Child Items
it is also possible to define multiple SidebarChildItem for every SidebarItem.
import 'package:animated_sidebar/animated_sidebar.dart';  
  
final List<SidebarItem> items = [  
  SidebarItem(icon: Icons.home, text: 'Home'),  
  SidebarItem(  
    icon: Icons.person,  
    text: 'Management',  
    children: [  
	  SidebarChildItem(icon: Icons.person, text: 'Users'),  
	  SidebarChildItem(icon: Icons.verified_user, text: 'Roles'),  
    ],  
  ),
];  
The Item Containing the Children is Collapsed and expand only on tap. If the Current selected item is a SidebarChildItem the overlying Item keeps expanded
Default usage of AnimatedSidebar
import 'package:animated_sidebar/animated_sidebar.dart';
@override
Widget build(BuildContext context) {
  return Scaffold(
    backgroundColor: Theme.of(context).scaffoldBackgroundColor,
    body: Row(
      children: [
        AnimatedSidebar(
          expanded: MediaQuery.of(context).size.width > 600,
          items: items,
          selectedIndex: 0,
          onItemSelected: (index) => print(index),
          headerIcon: Icons.ac_unit_sharp,
          headerIconColor: Colors.amberAccent,
          headerText: 'Example',
        ),
        Center(
          child: Text(
            'Page: $activeTab',
            style: Theme.of(context).textTheme.headline3,
          ),
        ),
      ],
    ),
  );
}
Use the AnimatedSidebar widget and handle state external :
import 'package:animated_sidebar/animated_sidebar.dart';
int activeTab = 0;
@override
Widget build(BuildContext context) {
  return Scaffold(
    backgroundColor: Theme.of(context).scaffoldBackgroundColor,
    body: Row(
      children: [
        AnimatedSidebar(
          expanded: MediaQuery.of(context).size.width > 600,
          items: items,
          selectedIndex: activeTab,
          autoSelectedIndex: false, // must be false if you want to handle state external
          onItemSelected: (index) =>
              setState(() => activeTab = index),
          headerIcon: Icons.ac_unit_sharp,
          headerIconColor: Colors.amberAccent,
          headerText: 'Example',
        ),
        Center(
          child: Text(
            'Page: $activeTab',
            style: Theme.of(context).textTheme.headline3,
          ),
        ),
      ],
    ),
  );
}