dropdown_search 5.0.2

Simple and robust Searchable Dropdown with item search feature, making it possible to use an offline item list or filtering URL for easy customization.

example/lib/main.dart

import 'package:dropdown_search/dropdown_search.dart';
import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'dropdownSearch Demo',
      //enable this line if you want test Dark Mode
      //theme: ThemeData.dark(),
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  final myKey = GlobalKey<DropdownSearchState<MultiLevelString>>();
  final List<MultiLevelString> myItems = [
    MultiLevelString(level1: "1"),
    MultiLevelString(level1: "2"),
    MultiLevelString(
      level1: "3",
      subLevel: [
        MultiLevelString(level1: "sub3-1"),
        MultiLevelString(level1: "sub3-2"),
      ],
    ),
    MultiLevelString(level1: "4")
  ];

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(),
      body: Padding(
        padding: EdgeInsets.all(8),
        child: DropdownSearch<MultiLevelString>(
          key: myKey,
          items: myItems,
          compareFn: (i1, i2) => i1.level1 == i2.level1,
          popupProps: PopupProps.menu(
            showSelectedItems: true,
            interceptCallBacks: true,
            itemBuilder: (ctx, item, isSelected) {
              return ListTile(
                selected: isSelected,
                title: Text(item.level1),
                trailing: item.subLevel.isEmpty
                    ? null
                    : (item.isExpanded
                        ? IconButton(
                            icon: Icon(Icons.arrow_drop_down),
                            onPressed: () {
                              item.isExpanded = !item.isExpanded;
                              myKey.currentState?.updatePopupState();
                            },
                          )
                        : IconButton(
                            icon: Icon(Icons.arrow_right),
                            onPressed: () {
                              item.isExpanded = !item.isExpanded;
                              myKey.currentState?.updatePopupState();
                            },
                          )),
                subtitle: item.subLevel.isNotEmpty && item.isExpanded
                    ? Container(
                        height: item.subLevel.length * 50,
                        child: ListView(
                          children: item.subLevel
                              .map(
                                (e) => ListTile(
                                  selected: myKey.currentState?.getSelectedItem
                                          ?.level1 ==
                                      e.level1,
                                  title: Text(e.level1),
                                  onTap: () {
                                    myKey.currentState?.popupValidate([e]);
                                  },
                                ),
                              )
                              .toList(),
                        ),
                      )
                    : null,
                onTap: () => myKey.currentState?.popupValidate([item]),
              );
            },
          ),
        ),
      ),
    );
  }
}

class MultiLevelString {
  final String level1;
  final List<MultiLevelString> subLevel;
  bool isExpanded;

  MultiLevelString({
    this.level1 = "",
    this.subLevel = const [],
    this.isExpanded = false,
  });

  MultiLevelString copy({
    String? level1,
    List<MultiLevelString>? subLevel,
    bool? isExpanded,
  }) =>
      MultiLevelString(
        level1: level1 ?? this.level1,
        subLevel: subLevel ?? this.subLevel,
        isExpanded: isExpanded ?? this.isExpanded,
      );

  @override
  String toString() => level1;
}