Flutter DropdownSearch

Flutter simple and robust DropdownSearch with item search feature, making it possible to use an offline item list or filtering URL for easy customization.

Key Features

Online and offline items
Searchable dropdown
Three dropdown mode: Menu/ BottomSheet/ Dialog
Material dropdown
Easy customizable UI
Handle Light and Dark theme
Easy implementation into statelessWidget

packages.yaml

dropdown_search: <lastest version>

Import

import 'package:dropdown_search/dropdown_search.dart';

Simple implementation

DropdownSearch<String>(
    mode: Mode.MENU,
    showSelectedItem: true,
    items: ["Brazil", "Italia (Disabled)", "Tunisia", 'Canada'],
    label: "Menu mode",
    hint: "country in menu mode",
    popupItemDisabled: (String s) => s.startsWith('I'),
    onChanged: print,
    selectedItem: "Brazil"),

customize showed field (itemAsString)

DropdownSearch<UserModel>(
  label: "Name",
  onFind: (String filter) => getData(filter),
  itemAsString: (UserModel u) => u.userAsStringByName(),
  onChanged: (UserModel data) => print(data),
),

DropdownSearch<UserModel>(
  label: "Name",
  onFind: (String filter) => getData(filter),
  itemAsString: (UserModel u) => u.userAsStringById(),
  onChanged: (UserModel data) => print(data),
),

customize Filter Function

DropdownSearch<UserModel>(
  label: "Name",
  filterFn: (user, filter) => user.userFilterByCreationDate(filter),
  onFind: (String filter) => getData(filter),
  itemAsString: (UserModel u) => u.userAsStringByName(),
  onChanged: (UserModel data) => print(data),
),

customize Search Mode

DropdownSearch<UserModel>(
  mode: Mode.BOTTOM_SHEET,
  label: "Name",
  onFind: (String filter) => getData(filter),
  itemAsString: (UserModel u) => u.userAsString(),
  onChanged: (UserModel data) => print(data),
),

Validation

DropdownSearch(
  items: ["Brazil", "France", "Tunisia", "Canada"],
  label: "Country",
  onChanged: print,
  selectedItem: "Tunisia",
  validator: (String item) {
    if (item == null)
      return "Required field";
    else if (item == "Brazil")
      return "Invalid item";
    else
      return null;
  },
);

Endpoint implementation (using Dio package)

DropdownSearch<UserModel>(
  label: "Name",
  onFind: (String filter) async {
    var response = await Dio().get(
        "http://5d85ccfb1e61af001471bf60.mockapi.io/user",
        queryParameters: {"filter": filter},
    );
    var models = UserModel.fromJsonList(response.data);
    return models;
  },
  onChanged: (UserModel data) {
    print(data);
  },
);

Layout customization

You can customize the layout of the DropdownSearch and its items. EXAMPLE

Properties	Description
`label`	DropDownSearch label
`showSearchBox`	show/hide the search box
`isFilteredOnline`	true if the filter on items is applied onlie (via API)
`showClearButton`	show/hide clear selected item
`items`	offline items list
`selectedItem`	selected item
`onFind`	function that returns item from API
`onChanged`	called when a new item is selected
`dropdownBuilder`	to customize list of items UI
`popupItemBuilder`	to customize selected item
`validator`	function to apply the validation formula
`searchBoxDecoration`	decoration for the search box
`popupBackgroundColor`	background color for the dialog/menu/bottomSheet
`popupTitle`	Custom widget for the popup title
`itemAsString`	customize the fields the be shown
`filterFn`	custom filter function
`enabled`	enable/disable dropdownSearch
`mode`	MENU / DIALOG/ BOTTOM_SHEET
`maxHeight`	the max height for dialog/bottomSheet/Menu
`dialogMaxWidth`	the max width for the dialog
`showSelectedItem`	manage selected item visibility (if true, the selected item will be highlighted)
`compareFn`	Function(T item, T selectedItem), custom comparing function
`dropdownSearchDecoration`	DropdownSearch input decoration
`emptyBuilder`	custom layout for empty results
`loadingBuilder`	custom layout for loading items
`errorBuilder`	custom layout for error
`autoFocusSearchBox`	the search box will be focused if true
`popupShape`	custom shape for the popup
`autoValidateMode`	handle auto validation mode
`onSaved`	An optional method to call with the final value when the form is saved via
`validator`	An optional method that validates an input. Returns an error string to display if the input is invalid, or null otherwise.
`clearButton`	customize clear button widget
`dropDownButton`	customize dropdown button widget
`dropdownBuilderSupportsNullItem`	If true, the dropdownBuilder will continue the uses of material behavior. This will be useful if you want to handle a custom UI only if the item !=null
`popupItemDisabled`	defines if an item of the popup is enabled or not, if the item is disabled, it cannot be clicked
`popupBarrierColor`	set a custom color for the popup barrier
`searchBoxController`	search box controller
`clearButtonBuilder`	custom clear button builder
`dropdownButtonBuilder`	custom dropdown button builder
`onBeforeChange`	callback executed before applying value change
`searchDelay`	delay before searching

Attention

To use a template as an item type, and you don’t want to use a custom fonction itemAsString and compareFn you need to implement toString, equals and hashcode, as shown below:

class UserModel {
  final String id;
  final DateTime createdAt;
  final String name;
  final String avatar;

  UserModel({this.id, this.createdAt, this.name, this.avatar});

  factory UserModel.fromJson(Map<String, dynamic> json) {
    if (json == null) return null;
    return UserModel(
      id: json["id"],
      createdAt:
          json["createdAt"] == null ? null : DateTime.parse(json["createdAt"]),
      name: json["name"],
      avatar: json["avatar"],
    );
  }

  static List<UserModel> fromJsonList(List list) {
    if (list == null) return null;
    return list.map((item) => UserModel.fromJson(item)).toList();
  }

  ///this method will prevent the override of toString
  String userAsString() {
    return '#${this.id} ${this.name}';
  }

  ///this method will prevent the override of toString
  bool userFilterByCreationDate(String filter) {
    return this?.createdAt?.toString()?.contains(filter);
  }

  ///custom comparing function to check if two users are equal
  bool isEqual(UserModel model) {
    return this?.id == model?.id;
  }

  @override
  String toString() => name;
}