drp_date_picker

A native Flutter Nepali (Bikram Sambat / BS) + English (Gregorian / AD) date picker. Every day cell shows both calendars. BS ↔ AD conversion included, with holiday support, min/max constraints, and form integration.

What is drp_date_picker?

drp_date_picker is a production-oriented Flutter date picker for applications that need to work with both the Nepali Bikram Sambat (BS) calendar and the English Gregorian (AD) calendar.

It solves: picking dates in BS while always keeping the AD equivalent in sync — and vice versa. No manual conversion, no hidden text fields.
Why it's different: most Nepali date pickers in Flutter only show one calendar or are thin wrappers. drp_date_picker renders both BS and AD on every day cell, ships a standalone conversion engine, supports developer-provided holidays and typed events, and integrates with Flutter Form natively.
Zero runtime dependencies — pure Flutter, no plugins.

Use cases

Nepali government & civic applications
School / college & university systems
HR / payroll systems
Accounting / ERP software
Banking & business applications
Booking & scheduling systems
Any app that must capture or display BS + AD dates
Apps with custom holiday calendars (Dashain, Tihar, national holidays, etc.)

Installation

flutter pub add drp_date_picker

Requires Dart >= 3.12 and Flutter >= 3.0 (Material 3 recommended but not required).

Quick start (30 seconds)

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

void main() => runApp(MaterialApp(home: Scaffold(body: Demo())));

class Demo extends StatelessWidget {
  const Demo({super.key});

  @override
  Widget build(BuildContext context) {
    return DrpDatePicker(
      onChanged: (date) {
        // date is a DrpDate carrying both calendars.
        print('BS: ${date?.bs.iso}  AD: ${date?.ad.iso}');
      },
    );
  }
}

That's it. The picker defaults to BS-primary mode (Nepali date in the input, English shown small in each cell), opens as an overlay anchored to the field, and supports keyboard and screen-reader-friendly interactions.

BS + AD support

Every date is returned as a DrpDate, which always carries both representations of the same instant:

onChanged: (DrpDate? date) {
  date?.bs.year; // BS year, e.g. 2082
  date?.bs.iso;  // '2082-02-27'
  date?.ad.year; // AD year, e.g. 2025
  date?.ad.iso;  // '2025-06-10'
}

Primary calendar (`type`)

type: DrpPickerType.bs (default) — grid driven by BS; BS shown large.
type: DrpPickerType.ad — grid driven by AD; AD shown large.

DrpDatePicker(type: DrpPickerType.ad);

Standalone conversion engine

DrpCalendar is a pure-Dart BS ↔ AD engine you can use without any UI:

final cal = DrpCalendar();

final bs = cal.engToNep(2025, 6, 10);      // BsDate(2082, 2, 27)
final ad = cal.nepToEng(2082, 2, 27);      // AdDate(2025, 6, 10)

cal.isValidBsDate('2082-02-27');           // true
cal.formatBs(bs!, 'DD MMMM YYYY');         // '27 Jestha 2082'
final month = cal.calendarMonthNep(2082, 2); // full month grid, both calendars

Supported ranges: BS 2000–2098 / AD 1944–2041.

Holidays & events

The calendar supports typed events — holidays, festivals, deadlines, bookings, and more — all shown as an accent dot with a tooltip. Dates are developer-provided and always specified in BS (canonical), regardless of the picker's type. Multiple events can fall on the same day.

Holidays (simple)

Use DrpHoliday (a thin, backward-compatible event subclass):

final holidays = [
  const DrpHoliday(date: BsDate(2082, 1, 1),  title: 'Nepali New Year'),
  const DrpHoliday(date: BsDate(2082, 7, 10), title: 'Vijaya Dashami'),
  const DrpHoliday(date: BsDate(2082, 10, 15), title: 'Tihar'),
];

DrpDatePicker(holidays: holidays);

Typed events (general)

For other calendar markers, use DrpCalendarEvent with a DrpEventType:

final events = [
  const DrpCalendarEvent(
    date: BsDate(2082, 2, 15),
    title: 'Office closed',
    type: DrpEventType.event,       // holiday | festival | event | deadline | custom
  ),
  const DrpCalendarEvent(
    date: BsDate(2082, 2, 28),
    title: 'Salary day',
    type: DrpEventType.deadline,
    color: Colors.green,            // optional per-event colour
  ),
];

DrpDatePicker(events: events);

events and holidays can be combined.
Days with events show a single dot (first event's colour) and a tooltip listing all titles.
DrpHoliday is just DrpCalendarEvent with type: DrpEventType.holiday, so it can also be placed in the events list.

No events are hard-coded. Build the lists from your own data, an API, or a static file.

Configuration

Parameter	Type	Default	Description
`type`	`DrpPickerType`	`bs`	Calendar that drives the grid (`bs` \| `ad`)
`initialDate`	`DrpDate?`	—	Initial selection (uncontrolled)
`selectedDate`	`DrpDate?`	—	Controlled selection (picker follows it)
`minDate` / `minDateAd`	`BsDate?` / `AdDate?`	—	Earliest selectable date (inclusive)
`maxDate` / `maxDateAd`	`BsDate?` / `AdDate?`	—	Latest selectable date (inclusive)
`disabledDates`	`List<BsDate>`	`[]`	Specific BS dates to disable
`events`	`List<DrpCalendarEvent>`	`[]`	Developer-provided typed events (holidays, festivals, deadlines, ...)
`holidays`	`List<DrpHoliday>`	`[]`	Deprecated. Holiday shortcut for `events`
`markSaturday`	`bool`	`true`	Highlight Saturdays in the accent colour
`digits`	`DrpDigits`	`english`	`english` \| `devanagari` numerals
`firstDayOfWeek`	`int`	`0`	`0`=Sunday … `6`=Saturday
`format`	`String?`	—	Display format (tokens below)
`placeholder`	`String?`	—	Input hint text
`popupMode`	`DrpPopupMode`	`popup`	`popup` \| `inline`
`enabled`	`bool`	`true`	Enable/disable the field
`theme`	`DrpDatePickerTheme?`	—	Styling override

minDate / maxDate can be given in either BS or AD (or both); the picker enforces whichever is tighter.

Format tokens

Used by the format parameter. Numeric tokens respect the digits setting.

Token	Example (BS)	Example (AD)
`YYYY`	`2082`	`2025`
`YY`	`82`	`25`
`MMMM`	`Jestha`	`June`
`MM`	`02`	`06`
`M`	`2`	`6`
`DD`	`27`	`27`
`D`	`27`	`27`

DrpDatePicker(format: 'DD MMMM YYYY'); // '27 Jestha 2082' (BS) / '10 June 2025' (AD)

Callbacks

Callback	Signature	When
`onChanged`	`ValueChanged<DrpDate?>`	Any selection or clear (both calendars)
`onChangedBS`	`ValueChanged<BsDate?>`	Selection/clear, BS-only
`onChangedAD`	`ValueChanged<AdDate?>`	Selection/clear, AD-only
`onPanelOpen`	`VoidCallback`	Popup opens
`onPanelClose`	`VoidCallback`	Popup closes

DrpDatePicker(
  onChanged: (d) => save(d),
  onChangedBS: (bs) => log('BS ${bs?.iso}'),
  onChangedAD: (ad) => log('AD ${ad?.iso}'),
);

Form usage

Use DrpDatePickerFormField (a FormField<DrpDate?>) or the convenience DrpDatePickerTextFormField to integrate with Flutter's Form — validation, autovalidateMode, onSaved, and required-field behaviour all work.

final _formKey = GlobalKey<FormState>();

Form(
  key: _formKey,
  child: Column(
    children: [
      DrpDatePickerTextFormField(
        label: 'Delivery date',
        validator: (v) => v == null ? 'Please select a date' : null,
      ),
      ElevatedButton(
        onPressed: () => _formKey.currentState!.validate(),
        child: const Text('Submit'),
      ),
    ],
  ),
)

Customization

Style the picker globally through a ThemeExtension, or pass a DrpDatePickerTheme directly:

ThemeData(
  extensions: [
    const DrpDatePickerTheme(
      accent: Color(0xFFB3352B),
      today: Color(0xFF1F4B7A),
      panelBackground: Color(0xFFFFFFFF),
      radius: 14,
    ),
  ],
)

Available theme fields: accent, accentSoft, today, inputBackground, panelBackground, border, text, muted, holiday, radius. Unset fields fall back to sensible defaults from the ambient ColorScheme (dark-mode friendly).

Examples

example/ — a complete app demonstrating BS and AD modes, holidays, Devanagari digits, inline layout, min/max, and form validation.

Run it:

cd example
flutter run

Troubleshooting

The popup doesn't open — make sure enabled: true and the widget is inside a MaterialApp (it needs an Overlay). If you're using popupMode: inline, no overlay is used.

Holidays don't show — holiday dates must be in BS format (BsDate). If your source data is AD, convert with DrpCalendar().engToNep(...) first. Dates outside BS 2000–2098 are ignored.

I want the input in English but the grid in Nepali (or vice versa) — set type to control the grid and format/digits to control display.

Contributing

Contributions are welcome. Please:

Fork the repository.
Make changes on a feature branch.
Run flutter analyze and flutter test.
Open a pull request.

Guidelines: keep it dependency-free, maintain backward compatibility, add tests for new behaviour.

License

MIT — see LICENSE.

drp_date_picker

What is drp_date_picker?

Use cases

Installation

Quick start (30 seconds)

BS + AD support

Primary calendar (`type`)

Standalone conversion engine

Holidays & events

Holidays (simple)

Typed events (general)

Configuration

Format tokens

Callbacks

Form usage

Customization

Examples

Troubleshooting

Contributing

License

Libraries

drp_date_picker package

drp_date_picker

What is drp_date_picker?

Use cases

Installation

Quick start (30 seconds)

BS + AD support

Primary calendar (type)

Standalone conversion engine

Holidays & events

Holidays (simple)

Typed events (general)

Configuration

Format tokens

Callbacks

Form usage

Customization

Examples

Troubleshooting

Contributing

License

Libraries

drp_date_picker package

Primary calendar (`type`)