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.

Flutter-DropdownSearch

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

Flutter-DropdownSearchv

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;
}

GitHub