region_settings

A Flutter plugin to get device region settings such as measurement system, temperature units, and date formats.

Platform Support

Android	iOS	MacOS	Web	Linux	Windows
✅	✅

Usage

To use this plugin, add region_settings as a dependency in your pubspec.yaml file.

Call RegionSettings to access device region settings including temperature unit, measurement system, and date format preferences:

import 'package:region_settings/region_settings.dart';

final RegionSettings regionSettings = await RegionSettings.getSettings();
TemperatureUnit temperatureUnits = regionSettings.temperatureUnits;
bool usesMetricSystem = regionSettings.usesMetricSystem;
int firstDayOfWeek = regionSettings.firstDayOfWeek;
String dateFormatShort = regionSettings.dateFormat.short;
String dateFormatMedium = regionSettings.dateFormat.medium;
String dateFormatLong = regionSettings.dateFormat.long;

temperatureUnits is set to an enum with the following possible values:

enum	value
TemperatureUnit.celsius	'C'
TemperatureUnit.fahrenheit	'F'

firstDayOfWeek is an integer in the range 1..7, where 1 is Monday and 7 is Sunday. This value corresponds to the dart:core DateTime weekday property, and can be compared to constants such as DateTime.monday, as demonstrated in the example app.

The three dateFormat values are the date formatting patterns used by the device's locale and/or region settings. For example, the UK English short date format is typically 'dd/MM/y', while US English uses 'MM/dd/y'. Pass the date format pattern to a function like intl DateFormat to use this in a Flutter app.

iOS Implementation

Measurement System and Temperature Units

This plugin accesses Language & Region settings on iOS. Users can specify a Temperature preference (degrees C or degrees F) and a Measurement System preference (US, UK, or Metric). For the purposes of this plugin, the UK Measurement System is considered equivalent to Metric.

Note that the Temperature preference is not always honored when running on iOS simulators; however, it is reported correctly on physical devices.

First Day of Week

iOS 16 and later add a First Day of Week preference to Language & Region. iOS allows selecting any of day of the week. To surface the user's first day of week preference, the First Day of Week setting is used by this plugin, if available. On older versions of iOS that lack this setting, the plugin falls back to assuming the first day of week based on the device's locale. See Table of First Day of Week by Country below.

Date Format

The plugin gets date format patterns from iOS. On older versions of iOS, the date format pattern depends on the device's language setting. iOS 16 and later add a Date Format preference to Language & Region, which allows the user to change the date format independently of the language's default date format, including even the separator character.

Android Implementation

Measurement System

Android does not have an OS-level measurement system setting. Instead, the plugin must guess the measurement system based on the device's locale. The plugin considers the following countries to be non-Metric:

• American Samoa (US)
• Bahamas
• Belize
• Cayman Islands
• Guam (US)
• Liberia
• Marshall Islands
• Micronesia
• Northern Mariana Islands (US)
• Palau
• Turks and Caicos Islands
• United States
• US Minor Outlying Islands
• US Virgin Islands

All other countries are considered to be Metric users.

If the above list of countries is found to be inaccurate, please submit an issue or PR.

Temperature Units

Android 14 and later include a separate Temperature preference in Regional Preferences. If available, the plugin will use this setting. If not available, the plugin will fall back to the locale, where Metric countries are assumed to use Celsius and non-Metric countries are assumed to use Fahrenheit.

First Day of Week

Android 14 and later add a First Day of Week preference to Regional Preferences. Android allows selecting any of day of the week. To surface the user's first day of week preference, the First Day of Week setting is used by this plugin, if available. On older versions of Android that lack this setting, the plugin falls back to assuming the first day of week based on the device's locale. See Table of First Day of Week by Country below.

Date Format

Android date formats are based on the device's locale. However, fetching the date format pattern is only possible in API 26 (Oreo) and later. The plugin will do this on supported versions of Android. On older versions of Android, the plugin falls back to standard patterns that should be recognizable worldwide, such as 'yyyy-MM-dd' for the short date.

Table of First Day of Week by Country

In most countries, Monday or Sunday are considered the first day of the week, with Friday or Saturday also used in some places. The following table shows how this plugin determines which countries use which day. This list was sourced from https://github.com/unicode-org/cldr.

Monday	Friday	Saturday	Sunday
All other countries	Maldives	American Samoa (US)	Antigua and Barbuda
		Afghanistan	Australia
		Algeria	Bahamas
		Bahrain	Bangladesh
		Djibouti	Belize
		Egypt	Bhutan
		Iran	Botswana
		Iraq	Brazil
		Jordan	Cambodia
		Kuwait	Canada
		Libya	China
		Oman	Colombia
		Qatar	Dominica
		Sudan	Dominican Republic
		Syria	El Salvador
		United Arab Emirates	Ethiopia
			Guam (US)
			Guatemala
			Honduras
			Hong Kong
			India
			Indonesia
			Israel
			Jamaica
			Japan
			Kenya
			Laos
			Macau
			Malta
			Marshall Islands
			Mexico
			Mozambique
			Myanmar
			Nepal
			Nicaragua
			Pakistan
			Panama
			Paraguay
			Peru
			Philippines
			Portugal
			Puerto Rico
			Samoa
			Saudi Arabia
			Singapore
			South Africa
			South Korea
			Taiwan
			Thailand
			Trinidad and Tobago
			United States
			US Minor Outlying Islands
			US Virgin Islands
			Venezuela
			Yemen
			Zimbabwe

If the above list of countries is found to be inaccurate, please submit an issue or PR.

About

This plugin was written primarily to improve support for region defaults in Cuppa.

Author: Nathan Cosgray