packages/flutter/lib/src/material/material_localizations.dart - mirrors/flutter - Git at Google

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 import 'dart:async';

 import 'package:flutter/foundation.dart';
 import 'package:flutter/widgets.dart';
 import 'package:intl/intl.dart' as intl;
 import 'package:intl/date_symbols.dart' as intl;
 import 'package:intl/date_symbol_data_local.dart' as intl_local_date_data;

 import 'i18n/localizations.dart';
 import 'time.dart';
 import 'typography.dart';

 /// Defines the localized resource values used by the Material widgets.
 ///
 /// See also:
 ///
 ///  * [DefaultMaterialLocalizations], which implements this interface
 ///    and supports a variety of locales.
 abstract class MaterialLocalizations {
   /// The tooltip for the leading [AppBar] menu (aka 'hamburger') button.
   String get openAppDrawerTooltip;

   /// The [BackButton]'s tooltip.
   String get backButtonTooltip;

   /// The [CloseButton]'s tooltip.
   String get closeButtonTooltip;

   /// The tooltip for the [MonthPicker]'s "next month" button.
   String get nextMonthTooltip;

   /// The tooltip for the [MonthPicker]'s "previous month" button.
   String get previousMonthTooltip;

   /// The tooltip for the [PaginatedDataTable]'s "next page" button.
   String get nextPageTooltip;

   /// The tooltip for the [PaginatedDataTable]'s "previous page" button.
   String get previousPageTooltip;

   /// The default [PopupMenuButton] tooltip.
   String get showMenuTooltip;

   /// The default title for [AboutListTile].
   String aboutListTileTitle(String applicationName);

   /// Title for the [LicensePage] widget.
   String get licensesPageTitle;

   /// Title for the [PaginatedDataTable]'s row info footer.
   String pageRowsInfoTitle(int firstRow, int lastRow, int rowCount, bool rowCountIsApproximate);

   /// Title for the [PaginatedDataTable]'s "rows per page" footer.
   String get rowsPerPageTitle;

   /// Title for the [PaginatedDataTable]'s selected row count header.
   String selectedRowCountTitle(int selectedRowCount);

   /// Label for "cancel" buttons and menu items.
   String get cancelButtonLabel;

   /// Label for "close" buttons and menu items.
   String get closeButtonLabel;

   /// Label for "continue" buttons and menu items.
   String get continueButtonLabel;

   /// Label for "copy" edit buttons and menu items.
   String get copyButtonLabel;

   /// Label for "cut" edit buttons and menu items.
   String get cutButtonLabel;

   /// Label for OK buttons and menu items.
   String get okButtonLabel;

   /// Label for "paste" edit buttons and menu items.
   String get pasteButtonLabel;

   /// Label for "select all" edit buttons and menu items.
   String get selectAllButtonLabel;

   /// Label for the [AboutDialog] button that shows the [LicensePage].
   String get viewLicensesButtonLabel;

   /// The abbreviation for ante meridiem (before noon) shown in the time picker.
   String get anteMeridiemAbbreviation;

   /// The abbreviation for post meridiem (after noon) shown in the time picker.
   String get postMeridiemAbbreviation;

   /// The format used to lay out the time picker.
   ///
   /// The documentation for [TimeOfDayFormat] enum values provides details on
   /// each supported layout.
   TimeOfDayFormat get timeOfDayFormat;

   /// Provides geometric text preferences for the current locale.
   ///
   /// This text theme is incomplete. For example, it lacks text color
   /// information. This theme must be merged with another text theme that
   /// provides the missing values. The text styles provided by this theme have
   /// their [TextStyle.inherit] property set to true.
   ///
   /// Typically a complete theme is obtained via [Theme.of], which can be
   /// localized using the [Localizations] widget.
   ///
   /// See also: https://material.io/guidelines/style/typography.html
   TextTheme get localTextGeometry;

   /// Formats [TimeOfDay.hour] in the given time of day according to the value
   /// of [timeOfDayFormat].
   String formatHour(TimeOfDay timeOfDay);

   /// Formats [TimeOfDay.minute] in the given time of day according to the value
   /// of [timeOfDayFormat].
   String formatMinute(TimeOfDay timeOfDay);

   /// Formats [timeOfDay] according to the value of [timeOfDayFormat].
   String formatTimeOfDay(TimeOfDay timeOfDay);

   /// Full unabbreviated year format, e.g. 2017 rather than 17.
   String formatYear(DateTime date);

   /// Formats the date using a medium-width format.
   ///
   /// Abbreviates month and days of week. This appears in the header of the date
   /// picker invoked using [showDatePicker].
   ///
   /// Examples:
   ///
   /// - US English: Wed, Sep 27
   /// - Russian: ср, сент. 27
   String formatMediumDate(DateTime date);

   /// Formats the month and the year of the given [date].
   ///
   /// The returned string does not contain the day of the month. This appears
   /// in the date picker invoked using [showDatePicker].
   String formatMonthYear(DateTime date);

   /// List of week day names in narrow format, usually 1- or 2-letter
   /// abbreviations of full names.
   ///
   /// The list begins with the value corresponding to Sunday and ends with
   /// Saturday. Use [firstDayOfWeekIndex] to find the first day of week in this
   /// list.
   ///
   /// Examples:
   ///
   /// - US English: S, M, T, W, T, F, S
   /// - Russian: вс, пн, вт, ср, чт, пт, сб - notice that the list begins with
   ///   вс (Sunday) even though the first day of week for Russian is Monday.
   List<String> get narrowWeekDays;

   /// Index of the first day of week, where 0 points to Sunday, and 6 points to
   /// Saturday.
   ///
   /// This getter is compatible with [narrowWeekDays]. For example:
   ///
   /// ```dart
   /// var localizations = MaterialLocalizations.of(context);
   /// // The name of the first day of week for the current locale.
   /// var firstDayOfWeek = localizations.narrowWeekDays[localizations.firstDayOfWeekIndex];
   /// ```
   int get firstDayOfWeekIndex;

   /// The `MaterialLocalizations` from the closest [Localizations] instance
   /// that encloses the given context.
   ///
   /// This method is just a convenient shorthand for:
   /// `Localizations.of<MaterialLocalizations>(context, MaterialLocalizations)`.
   ///
   /// References to the localized resources defined by this class are typically
   /// written in terms of this method. For example:
   ///
   /// ```dart
   /// tooltip: MaterialLocalizations.of(context).backButtonTooltip,
   /// ```
   static MaterialLocalizations of(BuildContext context) {
     return Localizations.of<MaterialLocalizations>(context, MaterialLocalizations);
   }
 }

 /// Localized strings for the material widgets.
 class DefaultMaterialLocalizations implements MaterialLocalizations {
   /// Constructs an object that defines the material widgets' localized strings
   /// for the given `locale`.
   ///
   /// [LocalizationsDelegate] implementations typically call the static [load]
   /// function, rather than constructing this class directly.
   DefaultMaterialLocalizations(this.locale)
       : assert(locale != null),
         this._localeName = _computeLocaleName(locale) {
     _loadDateIntlDataIfNotLoaded();

     if (localizations.containsKey(locale.languageCode))
       _nameToValue.addAll(localizations[locale.languageCode]);
     if (localizations.containsKey(_localeName))
       _nameToValue.addAll(localizations[_localeName]);

     const String kMediumDatePattern = 'E, MMM\u00a0d';
     if (intl.DateFormat.localeExists(_localeName)) {
       _fullYearFormat = new intl.DateFormat.y(_localeName);
       _mediumDateFormat = new intl.DateFormat(kMediumDatePattern, _localeName);
       _yearMonthFormat = new intl.DateFormat('yMMMM', _localeName);
     } else if (intl.DateFormat.localeExists(locale.languageCode)) {
       _fullYearFormat = new intl.DateFormat.y(locale.languageCode);
       _mediumDateFormat = new intl.DateFormat(kMediumDatePattern, locale.languageCode);
       _yearMonthFormat = new intl.DateFormat('yMMMM', locale.languageCode);
     } else {
       _fullYearFormat = new intl.DateFormat.y();
       _mediumDateFormat = new intl.DateFormat(kMediumDatePattern);
       _yearMonthFormat = new intl.DateFormat('yMMMM');
     }

     if (intl.NumberFormat.localeExists(_localeName)) {
       _decimalFormat = new intl.NumberFormat.decimalPattern(_localeName);
       _twoDigitZeroPaddedFormat = new intl.NumberFormat('00', _localeName);
     } else if (intl.NumberFormat.localeExists(locale.languageCode)) {
       _decimalFormat = new intl.NumberFormat.decimalPattern(locale.languageCode);
       _twoDigitZeroPaddedFormat = new intl.NumberFormat('00', locale.languageCode);
     } else {
       _decimalFormat = new intl.NumberFormat.decimalPattern();
       _twoDigitZeroPaddedFormat = new intl.NumberFormat('00');
     }
   }

   /// The locale for which the values of this class's localized resources
   /// have been translated.
   final Locale locale;

   final String _localeName;

   final Map<String, String> _nameToValue = <String, String>{};

   /// Formats numbers using variable length format with no zero padding.
   ///
   /// See also [_twoDigitZeroPaddedFormat].
   intl.NumberFormat _decimalFormat;

   /// Formats numbers as two-digits.
   ///
   /// If the number is less than 10, zero-pads it.
   intl.NumberFormat _twoDigitZeroPaddedFormat;

   /// Full unabbreviated year format, e.g. 2017 rather than 17.
   intl.DateFormat _fullYearFormat;

   intl.DateFormat _mediumDateFormat;

   intl.DateFormat _yearMonthFormat;

   static String _computeLocaleName(Locale locale) {
     final String localeName = locale.countryCode.isEmpty ? locale.languageCode : locale.toString();
     return intl.Intl.canonicalizedLocale(localeName);
   }

   // TODO(hmuller): the rules for mapping from an integer value to
   // "one" or "two" etc. are locale specific and an additional "few" category
   // is needed. See http://cldr.unicode.org/index/cldr-spec/plural-rules
   String _nameToPluralValue(int count, String key) {
     String text;
     if (count == 0)
       text = _nameToValue['${key}Zero'];
     else if (count == 1)
       text = _nameToValue['${key}One'];
     else if (count == 2)
       text = _nameToValue['${key}Two'];
     else if (count > 2)
       text = _nameToValue['${key}Many'];
     text ??= _nameToValue['${key}Other'];
     assert(text != null);
     return text;
   }

   @override
   String formatHour(TimeOfDay timeOfDay) {
     switch (hourFormat(of: timeOfDayFormat)) {
       case HourFormat.HH:
         return _twoDigitZeroPaddedFormat.format(timeOfDay.hour);
       case HourFormat.H:
         return formatDecimal(timeOfDay.hour);
       case HourFormat.h:
         final int hour = timeOfDay.hourOfPeriod;
         return formatDecimal(hour == 0 ? 12 : hour);
     }
     return null;
   }

   @override
   String formatMinute(TimeOfDay timeOfDay) {
     return _twoDigitZeroPaddedFormat.format(timeOfDay.minute);
   }

   @override
   String formatYear(DateTime date) {
     return _fullYearFormat.format(date);
   }

   @override
   String formatMediumDate(DateTime date) {
     return _mediumDateFormat.format(date);
   }

   @override
   String formatMonthYear(DateTime date) {
     return _yearMonthFormat.format(date);
   }

   @override
   List<String> get narrowWeekDays {
     return _fullYearFormat.dateSymbols.NARROWWEEKDAYS;
   }

   @override
   int get firstDayOfWeekIndex => (_fullYearFormat.dateSymbols.FIRSTDAYOFWEEK + 1) % 7;

   /// Formats a [number] using local decimal number format.
   ///
   /// Inserts locale-appropriate thousands separator, if necessary.
   String formatDecimal(int number) {
     return _decimalFormat.format(number);
   }

   @override
   String formatTimeOfDay(TimeOfDay timeOfDay) {
     // Not using intl.DateFormat for two reasons:
     //
     // - DateFormat supports more formats than our material time picker does,
     //   and we want to be consistent across time picker format and the string
     //   formatting of the time of day.
     // - DateFormat operates on DateTime, which is sensitive to time eras and
     //   time zones, while here we want to format hour and minute within one day
     //   no matter what date the day falls on.
     switch (timeOfDayFormat) {
       case TimeOfDayFormat.h_colon_mm_space_a:
         return '${formatHour(timeOfDay)}:${formatMinute(timeOfDay)} ${_formatDayPeriod(timeOfDay)}';
       case TimeOfDayFormat.H_colon_mm:
       case TimeOfDayFormat.HH_colon_mm:
         return '${formatHour(timeOfDay)}:${formatMinute(timeOfDay)}';
       case TimeOfDayFormat.HH_dot_mm:
         return '${formatHour(timeOfDay)}.${formatMinute(timeOfDay)}';
       case TimeOfDayFormat.a_space_h_colon_mm:
         return '${_formatDayPeriod(timeOfDay)} ${formatHour(timeOfDay)}:${formatMinute(timeOfDay)}';
       case TimeOfDayFormat.frenchCanadian:
         return '${formatHour(timeOfDay)} h ${formatMinute(timeOfDay)}';
     }

     return null;
   }

   String _formatDayPeriod(TimeOfDay timeOfDay) {
     switch (timeOfDay.period) {
       case DayPeriod.am:
         return anteMeridiemAbbreviation;
       case DayPeriod.pm:
         return postMeridiemAbbreviation;
     }
     return null;
   }

   @override
   String get openAppDrawerTooltip => _nameToValue['openAppDrawerTooltip'];

   @override
   String get backButtonTooltip => _nameToValue['backButtonTooltip'];

   @override
   String get closeButtonTooltip => _nameToValue['closeButtonTooltip'];

   @override
   String get nextMonthTooltip => _nameToValue['nextMonthTooltip'];

   @override
   String get previousMonthTooltip => _nameToValue['previousMonthTooltip'];

   @override
   String get nextPageTooltip => _nameToValue['nextPageTooltip'];

   @override
   String get previousPageTooltip => _nameToValue['previousPageTooltip'];

   @override
   String get showMenuTooltip => _nameToValue['showMenuTooltip'];

   @override
   String aboutListTileTitle(String applicationName) {
     final String text = _nameToValue['aboutListTileTitle'];
     return text.replaceFirst(r'$applicationName', applicationName);
   }

   @override
   String get licensesPageTitle => _nameToValue['licensesPageTitle'];

   @override
   String pageRowsInfoTitle(int firstRow, int lastRow, int rowCount, bool rowCountIsApproximate) {
     String text = rowCountIsApproximate ? _nameToValue['pageRowsInfoTitleApproximate'] : null;
     text ??= _nameToValue['pageRowsInfoTitle'];
     assert(text != null, 'A $locale localization was not found for pageRowsInfoTitle or pageRowsInfoTitleApproximate');
     // TODO(hansmuller): this could be more efficient.
     return text
       .replaceFirst(r'$firstRow', formatDecimal(firstRow))
       .replaceFirst(r'$lastRow', formatDecimal(lastRow))
       .replaceFirst(r'$rowCount', formatDecimal(rowCount));
   }

   @override
   String get rowsPerPageTitle => _nameToValue['rowsPerPageTitle'];

   @override
   String selectedRowCountTitle(int selectedRowCount) {
     return _nameToPluralValue(selectedRowCount, 'selectedRowCountTitle') // asserts on no match
       .replaceFirst(r'$selectedRowCount', formatDecimal(selectedRowCount));
   }

   @override
   String get cancelButtonLabel => _nameToValue['cancelButtonLabel'];

   @override
   String get closeButtonLabel => _nameToValue['closeButtonLabel'];

   @override
   String get continueButtonLabel => _nameToValue['continueButtonLabel'];

   @override
   String get copyButtonLabel => _nameToValue['copyButtonLabel'];

   @override
   String get cutButtonLabel => _nameToValue['cutButtonLabel'];

   @override
   String get okButtonLabel => _nameToValue['okButtonLabel'];

   @override
   String get pasteButtonLabel => _nameToValue['pasteButtonLabel'];

   @override
   String get selectAllButtonLabel => _nameToValue['selectAllButtonLabel'];

   @override
   String get viewLicensesButtonLabel => _nameToValue['viewLicensesButtonLabel'];

   @override
   String get anteMeridiemAbbreviation => _nameToValue['anteMeridiemAbbreviation'];

   @override
   String get postMeridiemAbbreviation => _nameToValue['postMeridiemAbbreviation'];

   /// The [TimeOfDayFormat] corresponding to one of the following supported
   /// patterns:
   ///
   ///  * `HH:mm`
   ///  * `HH.mm`
   ///  * `HH 'h' mm`
   ///  * `HH:mm น.`
   ///  * `H:mm`
   ///  * `h:mm a`
   ///  * `a h:mm`
   ///  * `ah:mm`
   ///
   /// See also:
   ///
   ///  * http://demo.icu-project.org/icu-bin/locexp?d_=en&_=en_US shows the
   ///    short time pattern used in locale en_US
   @override
   TimeOfDayFormat get timeOfDayFormat {
     final String icuShortTimePattern = _nameToValue['timeOfDayFormat'];

     assert(() {
       if (!_icuTimeOfDayToEnum.containsKey(icuShortTimePattern)) {
         throw new FlutterError(
           '"$icuShortTimePattern" is not one of the ICU short time patterns '
           'supported by the material library. Here is the list of supported '
           'patterns:\n  ' +
           _icuTimeOfDayToEnum.keys.join('\n  ')
         );
       }
       return true;
     }());

     return _icuTimeOfDayToEnum[icuShortTimePattern];
   }

   /// Looks up text geometry defined in [MaterialTextGeometry].
   @override
   TextTheme get localTextGeometry => MaterialTextGeometry.forScriptCategory(_nameToValue["scriptCategory"]);

   /// Creates an object that provides localized resource values for the
   /// for the widgets of the material library.
   ///
   /// This method is typically used to create a [LocalizationsDelegate].
   /// The [MaterialApp] does so by default.
   static Future<MaterialLocalizations> load(Locale locale) {
     return new SynchronousFuture<MaterialLocalizations>(new DefaultMaterialLocalizations(locale));
   }
 }

 const Map<String, TimeOfDayFormat> _icuTimeOfDayToEnum = const <String, TimeOfDayFormat>{
   'HH:mm': TimeOfDayFormat.HH_colon_mm,
   'HH.mm': TimeOfDayFormat.HH_dot_mm,
   "HH 'h' mm": TimeOfDayFormat.frenchCanadian,
   'HH:mm น.': TimeOfDayFormat.HH_colon_mm,
   'H:mm': TimeOfDayFormat.H_colon_mm,
   'h:mm a': TimeOfDayFormat.h_colon_mm_space_a,
   'a h:mm': TimeOfDayFormat.a_space_h_colon_mm,
   'ah:mm': TimeOfDayFormat.a_space_h_colon_mm,
 };

 /// Tracks if date i18n data has been loaded.
 bool _dateIntlDataInitialized = false;

 /// Loads i18n data for dates if it hasn't be loaded yet.
 ///
 /// Only the first invocation of this function has the effect of loading the
 /// data. Subsequent invocations have no effect.
 void _loadDateIntlDataIfNotLoaded() {
   if (!_dateIntlDataInitialized) {
     // The returned Future is intentionally dropped on the floor. The
     // function only returns it to be compatible with the async counterparts.
     // The Future has no value otherwise.
     intl_local_date_data.initializeDateFormatting();
     _dateIntlDataInitialized = true;
   }
 }
	// Copyright 2017 The Chromium Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	import 'dart:async';

	import 'package:flutter/foundation.dart';
	import 'package:flutter/widgets.dart';
	import 'package:intl/intl.dart' as intl;
	import 'package:intl/date_symbols.dart' as intl;
	import 'package:intl/date_symbol_data_local.dart' as intl_local_date_data;

	import 'i18n/localizations.dart';
	import 'time.dart';
	import 'typography.dart';

	/// Defines the localized resource values used by the Material widgets.
	///
	/// See also:
	///
	/// * [DefaultMaterialLocalizations], which implements this interface
	/// and supports a variety of locales.
	abstract class MaterialLocalizations {
	/// The tooltip for the leading [AppBar] menu (aka 'hamburger') button.
	String get openAppDrawerTooltip;

	/// The [BackButton]'s tooltip.
	String get backButtonTooltip;

	/// The [CloseButton]'s tooltip.
	String get closeButtonTooltip;

	/// The tooltip for the [MonthPicker]'s "next month" button.
	String get nextMonthTooltip;

	/// The tooltip for the [MonthPicker]'s "previous month" button.
	String get previousMonthTooltip;

	/// The tooltip for the [PaginatedDataTable]'s "next page" button.
	String get nextPageTooltip;

	/// The tooltip for the [PaginatedDataTable]'s "previous page" button.
	String get previousPageTooltip;

	/// The default [PopupMenuButton] tooltip.
	String get showMenuTooltip;

	/// The default title for [AboutListTile].
	String aboutListTileTitle(String applicationName);

	/// Title for the [LicensePage] widget.
	String get licensesPageTitle;

	/// Title for the [PaginatedDataTable]'s row info footer.
	String pageRowsInfoTitle(int firstRow, int lastRow, int rowCount, bool rowCountIsApproximate);

	/// Title for the [PaginatedDataTable]'s "rows per page" footer.
	String get rowsPerPageTitle;

	/// Title for the [PaginatedDataTable]'s selected row count header.
	String selectedRowCountTitle(int selectedRowCount);

	/// Label for "cancel" buttons and menu items.
	String get cancelButtonLabel;

	/// Label for "close" buttons and menu items.
	String get closeButtonLabel;

	/// Label for "continue" buttons and menu items.
	String get continueButtonLabel;

	/// Label for "copy" edit buttons and menu items.
	String get copyButtonLabel;

	/// Label for "cut" edit buttons and menu items.
	String get cutButtonLabel;

	/// Label for OK buttons and menu items.
	String get okButtonLabel;

	/// Label for "paste" edit buttons and menu items.
	String get pasteButtonLabel;

	/// Label for "select all" edit buttons and menu items.
	String get selectAllButtonLabel;

	/// Label for the [AboutDialog] button that shows the [LicensePage].
	String get viewLicensesButtonLabel;

	/// The abbreviation for ante meridiem (before noon) shown in the time picker.
	String get anteMeridiemAbbreviation;

	/// The abbreviation for post meridiem (after noon) shown in the time picker.
	String get postMeridiemAbbreviation;

	/// The format used to lay out the time picker.
	///
	/// The documentation for [TimeOfDayFormat] enum values provides details on
	/// each supported layout.
	TimeOfDayFormat get timeOfDayFormat;

	/// Provides geometric text preferences for the current locale.
	///
	/// This text theme is incomplete. For example, it lacks text color
	/// information. This theme must be merged with another text theme that
	/// provides the missing values. The text styles provided by this theme have
	/// their [TextStyle.inherit] property set to true.
	///
	/// Typically a complete theme is obtained via [Theme.of], which can be
	/// localized using the [Localizations] widget.
	///
	/// See also: https://material.io/guidelines/style/typography.html
	TextTheme get localTextGeometry;

	/// Formats [TimeOfDay.hour] in the given time of day according to the value
	/// of [timeOfDayFormat].
	String formatHour(TimeOfDay timeOfDay);

	/// Formats [TimeOfDay.minute] in the given time of day according to the value
	/// of [timeOfDayFormat].
	String formatMinute(TimeOfDay timeOfDay);

	/// Formats [timeOfDay] according to the value of [timeOfDayFormat].
	String formatTimeOfDay(TimeOfDay timeOfDay);

	/// Full unabbreviated year format, e.g. 2017 rather than 17.
	String formatYear(DateTime date);

	/// Formats the date using a medium-width format.
	///
	/// Abbreviates month and days of week. This appears in the header of the date
	/// picker invoked using [showDatePicker].
	///
	/// Examples:
	///
	/// - US English: Wed, Sep 27
	/// - Russian: ср, сент. 27
	String formatMediumDate(DateTime date);

	/// Formats the month and the year of the given [date].
	///
	/// The returned string does not contain the day of the month. This appears
	/// in the date picker invoked using [showDatePicker].
	String formatMonthYear(DateTime date);

	/// List of week day names in narrow format, usually 1- or 2-letter
	/// abbreviations of full names.
	///
	/// The list begins with the value corresponding to Sunday and ends with
	/// Saturday. Use [firstDayOfWeekIndex] to find the first day of week in this
	/// list.
	///
	/// Examples:
	///
	/// - US English: S, M, T, W, T, F, S
	/// - Russian: вс, пн, вт, ср, чт, пт, сб - notice that the list begins with
	/// вс (Sunday) even though the first day of week for Russian is Monday.
	List<String> get narrowWeekDays;

	/// Index of the first day of week, where 0 points to Sunday, and 6 points to
	/// Saturday.
	///
	/// This getter is compatible with [narrowWeekDays]. For example:
	///
	/// ```dart
	/// var localizations = MaterialLocalizations.of(context);
	/// // The name of the first day of week for the current locale.
	/// var firstDayOfWeek = localizations.narrowWeekDays[localizations.firstDayOfWeekIndex];
	/// ```
	int get firstDayOfWeekIndex;

	/// The `MaterialLocalizations` from the closest [Localizations] instance
	/// that encloses the given context.
	///
	/// This method is just a convenient shorthand for:
	/// `Localizations.of<MaterialLocalizations>(context, MaterialLocalizations)`.
	///
	/// References to the localized resources defined by this class are typically
	/// written in terms of this method. For example:
	///
	/// ```dart
	/// tooltip: MaterialLocalizations.of(context).backButtonTooltip,
	/// ```
	static MaterialLocalizations of(BuildContext context) {
	return Localizations.of<MaterialLocalizations>(context, MaterialLocalizations);
	}
	}

	/// Localized strings for the material widgets.
	class DefaultMaterialLocalizations implements MaterialLocalizations {
	/// Constructs an object that defines the material widgets' localized strings
	/// for the given `locale`.
	///
	/// [LocalizationsDelegate] implementations typically call the static [load]
	/// function, rather than constructing this class directly.
	DefaultMaterialLocalizations(this.locale)
	: assert(locale != null),
	this._localeName = _computeLocaleName(locale) {
	_loadDateIntlDataIfNotLoaded();

	if (localizations.containsKey(locale.languageCode))
	_nameToValue.addAll(localizations[locale.languageCode]);
	if (localizations.containsKey(_localeName))
	_nameToValue.addAll(localizations[_localeName]);

	const String kMediumDatePattern = 'E, MMM\u00a0d';
	if (intl.DateFormat.localeExists(_localeName)) {
	_fullYearFormat = new intl.DateFormat.y(_localeName);
	_mediumDateFormat = new intl.DateFormat(kMediumDatePattern, _localeName);
	_yearMonthFormat = new intl.DateFormat('yMMMM', _localeName);
	} else if (intl.DateFormat.localeExists(locale.languageCode)) {
	_fullYearFormat = new intl.DateFormat.y(locale.languageCode);
	_mediumDateFormat = new intl.DateFormat(kMediumDatePattern, locale.languageCode);
	_yearMonthFormat = new intl.DateFormat('yMMMM', locale.languageCode);
	} else {
	_fullYearFormat = new intl.DateFormat.y();
	_mediumDateFormat = new intl.DateFormat(kMediumDatePattern);
	_yearMonthFormat = new intl.DateFormat('yMMMM');
	}

	if (intl.NumberFormat.localeExists(_localeName)) {
	_decimalFormat = new intl.NumberFormat.decimalPattern(_localeName);
	_twoDigitZeroPaddedFormat = new intl.NumberFormat('00', _localeName);
	} else if (intl.NumberFormat.localeExists(locale.languageCode)) {
	_decimalFormat = new intl.NumberFormat.decimalPattern(locale.languageCode);
	_twoDigitZeroPaddedFormat = new intl.NumberFormat('00', locale.languageCode);
	} else {
	_decimalFormat = new intl.NumberFormat.decimalPattern();
	_twoDigitZeroPaddedFormat = new intl.NumberFormat('00');
	}
	}

	/// The locale for which the values of this class's localized resources
	/// have been translated.
	final Locale locale;

	final String _localeName;

	final Map<String, String> _nameToValue = <String, String>{};

	/// Formats numbers using variable length format with no zero padding.
	///
	/// See also [_twoDigitZeroPaddedFormat].
	intl.NumberFormat _decimalFormat;

	/// Formats numbers as two-digits.
	///
	/// If the number is less than 10, zero-pads it.
	intl.NumberFormat _twoDigitZeroPaddedFormat;

	/// Full unabbreviated year format, e.g. 2017 rather than 17.
	intl.DateFormat _fullYearFormat;

	intl.DateFormat _mediumDateFormat;

	intl.DateFormat _yearMonthFormat;

	static String _computeLocaleName(Locale locale) {
	final String localeName = locale.countryCode.isEmpty ? locale.languageCode : locale.toString();
	return intl.Intl.canonicalizedLocale(localeName);
	}

	// TODO(hmuller): the rules for mapping from an integer value to
	// "one" or "two" etc. are locale specific and an additional "few" category
	// is needed. See http://cldr.unicode.org/index/cldr-spec/plural-rules
	String _nameToPluralValue(int count, String key) {
	String text;
	if (count == 0)
	text = _nameToValue['${key}Zero'];
	else if (count == 1)
	text = _nameToValue['${key}One'];
	else if (count == 2)
	text = _nameToValue['${key}Two'];
	else if (count > 2)
	text = _nameToValue['${key}Many'];
	text ??= _nameToValue['${key}Other'];
	assert(text != null);
	return text;
	}

	@override
	String formatHour(TimeOfDay timeOfDay) {
	switch (hourFormat(of: timeOfDayFormat)) {
	case HourFormat.HH:
	return _twoDigitZeroPaddedFormat.format(timeOfDay.hour);
	case HourFormat.H:
	return formatDecimal(timeOfDay.hour);
	case HourFormat.h:
	final int hour = timeOfDay.hourOfPeriod;
	return formatDecimal(hour == 0 ? 12 : hour);
	}
	return null;
	}

	@override
	String formatMinute(TimeOfDay timeOfDay) {
	return _twoDigitZeroPaddedFormat.format(timeOfDay.minute);
	}

	@override
	String formatYear(DateTime date) {
	return _fullYearFormat.format(date);
	}

	@override
	String formatMediumDate(DateTime date) {
	return _mediumDateFormat.format(date);
	}

	@override
	String formatMonthYear(DateTime date) {
	return _yearMonthFormat.format(date);
	}

	@override
	List<String> get narrowWeekDays {
	return _fullYearFormat.dateSymbols.NARROWWEEKDAYS;
	}

	@override
	int get firstDayOfWeekIndex => (_fullYearFormat.dateSymbols.FIRSTDAYOFWEEK + 1) % 7;

	/// Formats a [number] using local decimal number format.
	///
	/// Inserts locale-appropriate thousands separator, if necessary.
	String formatDecimal(int number) {
	return _decimalFormat.format(number);
	}

	@override
	String formatTimeOfDay(TimeOfDay timeOfDay) {
	// Not using intl.DateFormat for two reasons:
	//
	// - DateFormat supports more formats than our material time picker does,
	// and we want to be consistent across time picker format and the string
	// formatting of the time of day.
	// - DateFormat operates on DateTime, which is sensitive to time eras and
	// time zones, while here we want to format hour and minute within one day
	// no matter what date the day falls on.
	switch (timeOfDayFormat) {
	case TimeOfDayFormat.h_colon_mm_space_a:
	return '${formatHour(timeOfDay)}:${formatMinute(timeOfDay)} ${_formatDayPeriod(timeOfDay)}';
	case TimeOfDayFormat.H_colon_mm:
	case TimeOfDayFormat.HH_colon_mm:
	return '${formatHour(timeOfDay)}:${formatMinute(timeOfDay)}';
	case TimeOfDayFormat.HH_dot_mm:
	return '${formatHour(timeOfDay)}.${formatMinute(timeOfDay)}';
	case TimeOfDayFormat.a_space_h_colon_mm:
	return '${_formatDayPeriod(timeOfDay)} ${formatHour(timeOfDay)}:${formatMinute(timeOfDay)}';
	case TimeOfDayFormat.frenchCanadian:
	return '${formatHour(timeOfDay)} h ${formatMinute(timeOfDay)}';
	}

	return null;
	}

	String _formatDayPeriod(TimeOfDay timeOfDay) {
	switch (timeOfDay.period) {
	case DayPeriod.am:
	return anteMeridiemAbbreviation;
	case DayPeriod.pm:
	return postMeridiemAbbreviation;
	}
	return null;
	}

	@override
	String get openAppDrawerTooltip => _nameToValue['openAppDrawerTooltip'];

	@override
	String get backButtonTooltip => _nameToValue['backButtonTooltip'];

	@override
	String get closeButtonTooltip => _nameToValue['closeButtonTooltip'];

	@override
	String get nextMonthTooltip => _nameToValue['nextMonthTooltip'];

	@override
	String get previousMonthTooltip => _nameToValue['previousMonthTooltip'];

	@override
	String get nextPageTooltip => _nameToValue['nextPageTooltip'];

	@override
	String get previousPageTooltip => _nameToValue['previousPageTooltip'];

	@override
	String get showMenuTooltip => _nameToValue['showMenuTooltip'];

	@override
	String aboutListTileTitle(String applicationName) {
	final String text = _nameToValue['aboutListTileTitle'];
	return text.replaceFirst(r'$applicationName', applicationName);
	}

	@override
	String get licensesPageTitle => _nameToValue['licensesPageTitle'];

	@override
	String pageRowsInfoTitle(int firstRow, int lastRow, int rowCount, bool rowCountIsApproximate) {
	String text = rowCountIsApproximate ? _nameToValue['pageRowsInfoTitleApproximate'] : null;
	text ??= _nameToValue['pageRowsInfoTitle'];
	assert(text != null, 'A $locale localization was not found for pageRowsInfoTitle or pageRowsInfoTitleApproximate');
	// TODO(hansmuller): this could be more efficient.
	return text
	.replaceFirst(r'$firstRow', formatDecimal(firstRow))
	.replaceFirst(r'$lastRow', formatDecimal(lastRow))
	.replaceFirst(r'$rowCount', formatDecimal(rowCount));
	}

	@override
	String get rowsPerPageTitle => _nameToValue['rowsPerPageTitle'];

	@override
	String selectedRowCountTitle(int selectedRowCount) {
	return _nameToPluralValue(selectedRowCount, 'selectedRowCountTitle') // asserts on no match
	.replaceFirst(r'$selectedRowCount', formatDecimal(selectedRowCount));
	}

	@override
	String get cancelButtonLabel => _nameToValue['cancelButtonLabel'];

	@override
	String get closeButtonLabel => _nameToValue['closeButtonLabel'];

	@override
	String get continueButtonLabel => _nameToValue['continueButtonLabel'];

	@override
	String get copyButtonLabel => _nameToValue['copyButtonLabel'];

	@override
	String get cutButtonLabel => _nameToValue['cutButtonLabel'];

	@override
	String get okButtonLabel => _nameToValue['okButtonLabel'];

	@override
	String get pasteButtonLabel => _nameToValue['pasteButtonLabel'];

	@override
	String get selectAllButtonLabel => _nameToValue['selectAllButtonLabel'];

	@override
	String get viewLicensesButtonLabel => _nameToValue['viewLicensesButtonLabel'];

	@override
	String get anteMeridiemAbbreviation => _nameToValue['anteMeridiemAbbreviation'];

	@override
	String get postMeridiemAbbreviation => _nameToValue['postMeridiemAbbreviation'];

	/// The [TimeOfDayFormat] corresponding to one of the following supported
	/// patterns:
	///
	/// * `HH:mm`
	/// * `HH.mm`
	/// * `HH 'h' mm`
	/// * `HH:mm น.`
	/// * `H:mm`
	/// * `h:mm a`
	/// * `a h:mm`
	/// * `ah:mm`
	///
	/// See also:
	///
	/// * http://demo.icu-project.org/icu-bin/locexp?d_=en&_=en_US shows the
	/// short time pattern used in locale en_US
	@override
	TimeOfDayFormat get timeOfDayFormat {
	final String icuShortTimePattern = _nameToValue['timeOfDayFormat'];

	assert(() {
	if (!_icuTimeOfDayToEnum.containsKey(icuShortTimePattern)) {
	throw new FlutterError(
	'"$icuShortTimePattern" is not one of the ICU short time patterns '
	'supported by the material library. Here is the list of supported '
	'patterns:\n ' +
	_icuTimeOfDayToEnum.keys.join('\n ')
	);
	}
	return true;
	}());

	return _icuTimeOfDayToEnum[icuShortTimePattern];
	}

	/// Looks up text geometry defined in [MaterialTextGeometry].
	@override
	TextTheme get localTextGeometry => MaterialTextGeometry.forScriptCategory(_nameToValue["scriptCategory"]);

	/// Creates an object that provides localized resource values for the
	/// for the widgets of the material library.
	///
	/// This method is typically used to create a [LocalizationsDelegate].
	/// The [MaterialApp] does so by default.
	static Future<MaterialLocalizations> load(Locale locale) {
	return new SynchronousFuture<MaterialLocalizations>(new DefaultMaterialLocalizations(locale));
	}
	}

	const Map<String, TimeOfDayFormat> _icuTimeOfDayToEnum = const <String, TimeOfDayFormat>{
	'HH:mm': TimeOfDayFormat.HH_colon_mm,
	'HH.mm': TimeOfDayFormat.HH_dot_mm,
	"HH 'h' mm": TimeOfDayFormat.frenchCanadian,
	'HH:mm น.': TimeOfDayFormat.HH_colon_mm,
	'H:mm': TimeOfDayFormat.H_colon_mm,
	'h:mm a': TimeOfDayFormat.h_colon_mm_space_a,
	'a h:mm': TimeOfDayFormat.a_space_h_colon_mm,
	'ah:mm': TimeOfDayFormat.a_space_h_colon_mm,
	};

	/// Tracks if date i18n data has been loaded.
	bool _dateIntlDataInitialized = false;

	/// Loads i18n data for dates if it hasn't be loaded yet.
	///
	/// Only the first invocation of this function has the effect of loading the
	/// data. Subsequent invocations have no effect.
	void _loadDateIntlDataIfNotLoaded() {
	if (!_dateIntlDataInitialized) {
	// The returned Future is intentionally dropped on the floor. The
	// function only returns it to be compatible with the async counterparts.
	// The Future has no value otherwise.
	intl_local_date_data.initializeDateFormatting();
	_dateIntlDataInitialized = true;
	}
	}