app_select_fields 0.0.2

Material 3 single-select and multi-select form fields for Flutter with a draggable bottom sheet, search, and lazy pagination — no extra dependencies.

app_select_fields

A Flutter dropdown / select field package: labelled, form-integrated single-select and multi-select inputs that open a draggable, root-level bottom sheet picker with built-in search, pagination and server-search hooks. Styled from the ambient Material 3 Theme by default — no configuration required, and no extra dependencies.

Useful as a Material dropdown alternative, multi-select chip picker, tag selector, or searchable option list in any Form.

Features

• AppSingleSelect<T> — radio-style picker, optional "Clear" action.
• AppMultiSelect<T> — checkbox picker with a live selection-count chip.
• Built-in search box, with optional debounced server-search callback.
• Optional lazy pagination (onLoadMore, hasMore, loadingMore).
• Works inside a Form via the standard validator API.
• AppSelectStyle to override radii, animation timing, text styles and the built-in English copy (search hint, button labels, "N selected").

Usage

import 'package:app_select_fields/app_select_fields.dart';

AppSingleSelect<String>(
  label: 'Country',
  hint: 'Select a country',
  options: const [
    SelectOption(label: 'United States', value: 'US'),
    SelectOption(label: 'United Kingdom', value: 'UK'),
  ],
  value: selectedCountry,
  onChanged: (value) => setState(() => selectedCountry = value),
);

AppMultiSelect<String>(
  label: 'Tags',
  options: const [
    SelectOption(label: 'Urgent', value: 'urgent'),
    SelectOption(label: 'Follow up', value: 'follow_up'),
  ],
  values: selectedTags,
  onChanged: (values) => setState(() => selectedTags = values),
);

Backend lazy loading / virtual scroll

For large or server-backed option lists, pass onLoadMore (infinite scroll, fired near the end of the list) and/or onSearchChanged (debounced server-search). The sheet's list is already a virtualized ListView.builder, so only visible rows are built regardless of list size — you just feed it pages as they arrive:

AppSingleSelect<String>(
  label: 'City',
  options: _cityOptions, // grows as pages arrive
  value: _city,
  hasMore: _cityHasMore,
  loadingMore: _cityLoadingMore,
  onLoadMore: () => _fetchNextPage(), // append results, update hasMore
  onSearchChanged: (query) => _fetchFirstPage(query), // replace options
  onChanged: (value) => setState(() => _city = value),
);

See example/ for a runnable demo of both widgets, including a fake paginated "backend" for AppSingleSelect and a custom AppSelectStyle.

AppSingleSelect<T> properties

Property	Type	Default	Description
label	String	required	Text shown above the field.
options	List<SelectOption<T>>	required	Options offered in the sheet.
hint	String?	null	Placeholder shown while nothing is selected.
value	T?	null	Currently selected value; the field is fully controlled by the caller.
onChanged	ValueChanged<T?>?	null	Called with the newly picked value when the sheet closes.
enabled	bool	true	Whether the field accepts interaction.
allowClear	bool	false	Shows a Clear button beside Cancel while value is non-null; calls onChanged(null).
loading	bool	false	Shows a spinner in place of the chevron and disables the field.
required	bool	false	Adds a red * to the label. Purely visual — pair with errorText/validator.
errorText	String?	null	Caller-driven validation message; takes precedence over validator.
validator	String? Function(T?)?	null	Form validator run against the selected value.
hasMore	bool	false	Whether a further page of options exists server-side. Ignored unless onLoadMore is set.
loadingMore	bool	false	Shows a loading row while the next page is fetched. Ignored unless onLoadMore is set.
onLoadMore	VoidCallback?	null	Fires when the sheet's list is scrolled past ~85%. Enables lazy pagination.
onSearchChanged	ValueChanged<String>?	null	Debounced (~400ms) server-search callback; disables local filtering when set.
displayLabel	bool	true	Whether label renders above the field, e.g. when a surrounding layout already names it.
style	AppSelectStyle	AppSelectStyle()	Visual/copy overrides — see below.
noRecordWidget	Widget?	null	Shown centered in the sheet's list area when options is empty. Defaults to a "No Records Found !" message.

AppMultiSelect<T> properties

Property	Type	Default	Description
label	String	required	Text shown above the field.
options	List<SelectOption<T>>	required	Options offered in the sheet.
hint	String?	null	Placeholder shown while nothing is selected.
values	List<T>	[]	Currently selected values; the field is fully controlled by the caller.
onChanged	ValueChanged<List<T>>?	null	Called with the confirmed values when the sheet's OK button is tapped.
maxSelectedLabel	int?	null	Once the selected count exceeds this, the trigger shows "N selected" instead of the joined labels.
enabled	bool	true	Whether the field accepts interaction.
validator	String? Function(List<T>?)?	null	Form validator run against the selected values.
style	AppSelectStyle	AppSelectStyle()	Visual/copy overrides — see below.
noRecordWidget	Widget?	null	Shown centered in the sheet's list area when options is empty. Defaults to a "No Records Found !" message.

SelectOption<T>

Property	Type	Description
label	String	Human-readable text shown in the list and trigger field.
value	T	The underlying value reported back via onChanged.

AppSelectStyle

Every field is optional and falls back to a Material 3 default or an English string.

Property	Type	Default	Description
borderRadius	double	12	Corner radius of the trigger field's border.
sheetBorderRadius	double	20	Corner radius of the sheet's top corners.
chevronAnimationDuration	Duration	150ms	How long the trigger's chevron takes to flip. Skipped when reduce-motion is on.
checkAnimationDuration	Duration	180ms	How long a radio dot / checkbox takes to animate. Skipped when reduce-motion is on.
labelStyle	TextStyle?	textTheme.labelMedium	Overrides the caption above the field.
hintStyle	TextStyle?	textTheme.bodyMedium	Overrides the placeholder text style.
textStyle	TextStyle?	textTheme.bodyMedium	Overrides the selected value's text style.
searchHint	String	'Search'	Placeholder for the sheet's search field.
cancelLabel	String	'Cancel'	Label of the button that closes the sheet without changes.
clearLabel	String	'Clear'	Label of the button that clears the current selection.
okLabel	String	'OK'	Label of the button that confirms a multi-select's choices.
selectedCountLabel	String Function(int)?	'$count selected'	Builds the "N selected" summary text.

AppSingleSelect<String>(
  label: 'Country',
  options: _countries,
  value: selectedCountry,
  onChanged: (value) => setState(() => selectedCountry = value),
  style: const AppSelectStyle(
    labelStyle: TextStyle(fontWeight: FontWeight.bold, color: Colors.indigo),
    hintStyle: TextStyle(fontStyle: FontStyle.italic, color: Colors.grey),
    textStyle: TextStyle(fontWeight: FontWeight.w600), // selected value's style
  ),
);

Author

Maintained by @TheTourist1502.