Localize time picker (#11967)

* Internationalize the time picker

- header layout and formatting
- 12-hour vs 24-hour dial
- RTL

* make TimeOfDayFormat an enum

* address comments

dev/tools/gen_localizations.dart

@@ -76,7 +76,7 @@ String generateLocalizationsMap() {
 const Map<String, Map<String, String>> localizations = const <String, Map<String, String>> {''');
 
   final String lastLocale = localeToResources.keys.last;
-  for (String locale in localeToResources.keys) {
+  for (String locale in localeToResources.keys.toList()..sort()) {
     output.writeln('  "$locale": const <String, String>{');
 
     final Map<String, String> resources = localeToResources[locale];
@@ -126,7 +126,7 @@ void main(List<String> args) {
     }
   }
 
-  final String regenerate = 'dart gen_localizations ${directory.path} ${args[1]}';
+  final String regenerate = 'dart dev/tools/gen_localizations.dart ${directory.path} ${args[1]}';
   print(outputHeader.replaceFirst('@(regenerate)', regenerate));
   print(generateLocalizationsMap());
 }

packages/flutter/lib/src/material/i18n/localizations.dart

@@ -4,134 +4,15 @@
 
 // This file has been automatically generated.  Please do not edit it manually.
 // To regenerate the file, use:
-// dart gen_localizations packages/flutter/lib/src/material/i18n material
+// dart dev/tools/gen_localizations.dart lib/src/material/i18n material
 
 /// Maps from [Locale.languageCode] to a map that contains the localized strings
 /// for that locale.
 ///
 /// This variable is used by [MaterialLocalizations].
 const Map<String, Map<String, String>> localizations = const <String, Map<String, String>> {
-  "sd": const <String, String>{
-    "openAppDrawerTooltip": r"اوپن جي مينڊيٽ مينيو",
-    "backButtonTooltip": r"پوئتي",
-    "closeButtonTooltip": r"بند ڪريو",
-    "nextMonthTooltip": r"ايندڙ مهيني",
-    "previousMonthTooltip": r"پويون مهينو",
-    "nextPageTooltip": r"اڳيون پيج",
-    "previousPageTooltip": r"پويون صفحو",
-    "showMenuTooltip": r"ڏيکاريو",
-    "licensesPageTitle": r"لائسنس",
-    "pageRowsInfoTitle": r"$firstRow–$lastRow جي $rowCount",
-    "pageRowsInfoTitleApproximate": r"$firstRow–$lastRow کان $rowCount تقريبن",
-    "rowsPerPageTitle": r"رني پاسي وارو صفحو",
-    "selectedRowCountTitleOther": r"$selectedRowCount شيون چونڊيل",
-    "cancelButtonLabel": r"منسوخ ڪيو",
-    "closeButtonLabel": r"بند ڪريو",
-    "continueButtonLabel": r"جاري رکو",
-    "copyButtonLabel": r"ڪاپي",
-    "cutButtonLabel": r"پٽي",
-    "okButtonLabel": r"ٺيڪ آهي",
-    "pasteButtonLabel": r"پيسٽ ڪريو",
-    "selectAllButtonLabel": r"سڀ چونڊيو",
-    "viewLicensesButtonLabel": r"لائسنس ڏسو"
-  },
-  "fa": const <String, String>{
-    "openAppDrawerTooltip": r"منوی ناوبری را باز کنید",
-    "backButtonTooltip": r"بازگشت",
-    "closeButtonTooltip": r"بستن",
-    "nextMonthTooltip": r"ماه بعد",
-    "previousMonthTooltip": r"ماه گذشته",
-    "nextPageTooltip": r"صفحه بعد",
-    "previousPageTooltip": r"صفحه قبلی",
-    "showMenuTooltip": r"نمایش منو",
-    "licensesPageTitle": r"مجوز",
-    "pageRowsInfoTitle": r"$firstRow–$lastRow از $rowCount",
-    "pageRowsInfoTitleApproximate": r"$firstRow–$lastRow از حدود $rowCount",
-    "rowsPerPageTitle": r"ردیف در صفحه:",
-    "selectedRowCountTitleOther": r"$selectedRowCount آیتم های انتخاب شده",
-    "cancelButtonLabel": r"لغو",
-    "closeButtonLabel": r"بستن",
-    "continueButtonLabel": r"ادامه دهید",
-    "copyButtonLabel": r"کپی",
-    "cutButtonLabel": r"برش",
-    "okButtonLabel": r"تایید",
-    "pasteButtonLabel": r"چسباندن",
-    "selectAllButtonLabel": r"انتخاب همه",
-    "viewLicensesButtonLabel": r"مشاهده مجوز"
-  },
-  "ur": const <String, String>{
-    "openAppDrawerTooltip": r"کھولیں نیویگیشن مینو",
-    "backButtonTooltip": r"واپس",
-    "closeButtonTooltip": r"بند کریں",
-    "nextMonthTooltip": r"اگلا مھینہ",
-    "previousMonthTooltip": r"پچھلا مھینہ",
-    "nextPageTooltip": r"اگلا صفحہ",
-    "previousPageTooltip": r"سابقہ ​​صفحہ",
-    "showMenuTooltip": r"مینو دکھائیں",
-    "licensesPageTitle": r"لائسنس",
-    "pageRowsInfoTitle": r"$firstRow–$lastRow کے $rowCount",
-    "pageRowsInfoTitleApproximate": r"$firstRow–$lastRow میں سے $rowCount تقریبا",
-    "rowsPerPageTitle": r"رویوں فی صفحہ:",
-    "selectedRowCountTitleOther": r"$selectedRowCount منتخب کردہ اشیاء",
-    "cancelButtonLabel": r"منسوخ کریں",
-    "closeButtonLabel": r"بند کریں",
-    "continueButtonLabel": r"جاری رکھیں",
-    "copyButtonLabel": r"کاپی",
-    "cutButtonLabel": r"کاٹیں",
-    "okButtonLabel": r"ٹھیک ہے",
-    "pasteButtonLabel": r"چسپاں",
-    "selectAllButtonLabel": r"تکاپیمام منتخب کریں",
-    "viewLicensesButtonLabel": r"لائسنس دیکھیں"
-  },
-  "ps": const <String, String>{
-    "openAppDrawerTooltip": r"د پرانیستی نیینګ مینو",
-    "backButtonTooltip": r"شاته",
-    "closeButtonTooltip": r"بنده",
-    "nextMonthTooltip": r"بله میاشت",
-    "previousMonthTooltip": r"تیره میاشت",
-    "nextPageTooltip": r"بله پاڼه",
-    "previousPageTooltip": r"مخکینی مخ",
-    "showMenuTooltip": r"غورنۍ ښودل",
-    "licensesPageTitle": r"جوازونه",
-    "pageRowsInfoTitle": r"$firstRow–$lastRow د $rowCount",
-    "pageRowsInfoTitleApproximate": r"$firstRow–$lastRow څخه $rowCount د",
-    "rowsPerPageTitle": r"د هرې پاڼې پاڼې:",
-    "selectedRowCountTitleOther": r"$selectedRowCount توکي غوره شوي",
-    "cancelButtonLabel": r"لغوه کول",
-    "closeButtonLabel": r"تړل",
-    "continueButtonLabel": r"منځپانګې",
-    "copyButtonLabel": r"کاپی",
-    "cutButtonLabel": r"کم کړئ",
-    "okButtonLabel": r"سمه ده",
-    "pasteButtonLabel": r"پیټ کړئ",
-    "selectAllButtonLabel": r"غوره کړئ",
-    "viewLicensesButtonLabel": r"لیدلس وګورئ"
-  },
-  "he": const <String, String>{
-    "openAppDrawerTooltip": r"פתח תפריט ניווט",
-    "backButtonTooltip": r"אחורה",
-    "closeButtonTooltip": r"סגור",
-    "nextMonthTooltip": r"חודש הבא",
-    "previousMonthTooltip": r"חודש שעבר",
-    "nextPageTooltip": r"עמוד הבא",
-    "previousPageTooltip": r"עמוד קודם",
-    "showMenuTooltip": r"הצג תפריט",
-    "licensesPageTitle": r"רישיונות",
-    "pageRowsInfoTitle": r"$firstRow–$lastRow מתוך $rowCount",
-    "pageRowsInfoTitleApproximate": r"$firstRow–$lastRow מתוך כ $rowCount",
-    "rowsPerPageTitle": r"שורות לעמוד:",
-    "selectedRowCountTitleOther": r"$selectedRowCount פריטים שנבחרו",
-    "cancelButtonLabel": r"ביטול",
-    "closeButtonLabel": r"סגור",
-    "continueButtonLabel": r"לְהַמשִׁיך",
-    "copyButtonLabel": r"קיבלתי!",
-    "cutButtonLabel": r"גזור",
-    "okButtonLabel": r"בסדר",
-    "pasteButtonLabel": r"הדבק",
-    "selectAllButtonLabel": r"בחר הכל",
-    "viewLicensesButtonLabel": r"ראה רישיונות"
-  },
   "ar": const <String, String>{
+    "timeOfDayFormat": r"h:mm a",
     "openAppDrawerTooltip": r"افتح قائمة التنقل",
     "backButtonTooltip": r"الى الخلف",
     "closeButtonTooltip": r"إغلا",
@@ -153,57 +34,77 @@ const Map<String, Map<String, String>> localizations = const <String, Map<String
     "okButtonLabel": r"حسنا",
     "pasteButtonLabel": r"عجين",
     "selectAllButtonLabel": r"اختر الكل",
-    "viewLicensesButtonLabel": r"عرض التراخيص"
+    "viewLicensesButtonLabel": r"عرض التراخيص",
+    "anteMeridiemAbbreviation": r"ص",
+    "postMeridiemAbbreviation": r"م"
   },
-  "it": const <String, String>{
-    "openAppDrawerTooltip": r"Apri il menu di navigazione",
-    "backButtonTooltip": r"Indietro",
-    "closeButtonTooltip": r"Chiudi",
-    "nextMonthTooltip": r"Il prossimo mese",
-    "previousMonthTooltip": r"Il mese scorso",
-    "nextPageTooltip": r"Pagina successiva",
-    "previousPageTooltip": r"Pagina precedente",
-    "showMenuTooltip": r"Mostra il menu",
-    "licensesPageTitle": r"Licenze",
-    "pageRowsInfoTitle": r"$firstRow–$lastRow di $rowCount",
-    "pageRowsInfoTitleApproximate": r"$firstRow–$lastRow di circa $rowCount",
-    "rowsPerPageTitle": r"Righe per pagina:",
-    "selectedRowCountTitleOther": r"$selectedRowCount selezionati",
-    "cancelButtonLabel": r"ANNULLA",
-    "closeButtonLabel": r"CHIUDI",
-    "continueButtonLabel": r"CONTINUA",
-    "copyButtonLabel": r"COPY",
-    "cutButtonLabel": r"TAGLIARE",
+  "de": const <String, String>{
+    "timeOfDayFormat": r"HH:mm",
+    "openAppDrawerTooltip": r"Navigationsmenü öffnen",
+    "backButtonTooltip": r"Zurück",
+    "closeButtonTooltip": r"Schließen",
+    "nextMonthTooltip": r"Nächster Monat",
+    "previousMonthTooltip": r"Vorheriger Monat",
+    "nextPageTooltip": r"Nächste Seite",
+    "previousPageTooltip": r"Vorherige Seite",
+    "showMenuTooltip": r"Menü anzeigen",
+    "licensesPageTitle": r"Lizenzen",
+    "pageRowsInfoTitle": r"$firstRow–$lastRow von $rowCount",
+    "pageRowsInfoTitleApproximate": r"$firstRow–$lastRow von etwa $rowCount",
+    "rowsPerPageTitle": r"Zeilen pro Seite:",
+    "selectedRowCountTitleZero": r"Keine Objekte ausgewählt",
+    "selectedRowCountTitleOne": r"1 Objekt ausgewählt",
+    "selectedRowCountTitleOther": r"$selectedRowCount Objekte ausgewählt",
+    "cancelButtonLabel": r"ABBRECHEN",
+    "closeButtonLabel": r"SCHLIESSEN",
+    "continueButtonLabel": r"FORTSETZEN",
+    "copyButtonLabel": r"KOPIEREN",
+    "cutButtonLabel": r"AUSSCHNEIDEN",
     "okButtonLabel": r"OK",
-    "pasteButtonLabel": r"INCOLLA",
-    "selectAllButtonLabel": r"SELEZIONA TUTTO",
-    "viewLicensesButtonLabel": r"VEDI LE LICENZE"
+    "pasteButtonLabel": r"EINFÜGEN",
+    "selectAllButtonLabel": r"ALLES AUSWÄHLEN",
+    "viewLicensesButtonLabel": r"LIZENZEN ANZEIGEN"
   },
-  "pt": const <String, String>{
-    "openAppDrawerTooltip": r"Abrir menu de navegação",
-    "backButtonTooltip": r"Costas",
-    "closeButtonTooltip": r"Fechar",
-    "nextMonthTooltip": r"Próximo mês",
-    "previousMonthTooltip": r"Mês anterior",
-    "nextPageTooltip": r"Próxima página",
-    "previousPageTooltip": r"Página anterior",
-    "showMenuTooltip": r"Mostrar menu",
-    "licensesPageTitle": r"Licenças",
-    "pageRowsInfoTitle": r"$firstRow–$lastRow de $rowCount",
-    "pageRowsInfoTitleApproximate": r"$firstRow–$lastRow de cerca de $rowCount",
-    "rowsPerPageTitle": r"Linhas por página:",
-    "selectedRowCountTitleOther": r"$selectedRowCount selecionados",
-    "cancelButtonLabel": r"CANCELAR",
-    "closeButtonLabel": r"FECHAR",
-    "continueButtonLabel": r"CONTINUAR",
-    "copyButtonLabel": r"CÓPIA DE",
-    "cutButtonLabel": r"CORTA",
+  "en": const <String, String>{
+    "timeOfDayFormat": r"h:mm a",
+    "openAppDrawerTooltip": r"Open navigation menu",
+    "backButtonTooltip": r"Back",
+    "closeButtonTooltip": r"Close",
+    "nextMonthTooltip": r"Next month",
+    "previousMonthTooltip": r"Previous month",
+    "nextPageTooltip": r"Next page",
+    "previousPageTooltip": r"Previous page",
+    "showMenuTooltip": r"Show menu",
+    "licensesPageTitle": r"Licenses",
+    "pageRowsInfoTitle": r"$firstRow–$lastRow of $rowCount",
+    "pageRowsInfoTitleApproximate": r"$firstRow–$lastRow of about $rowCount",
+    "rowsPerPageTitle": r"Rows per page:",
+    "selectedRowCountTitleZero": r"No items selected",
+    "selectedRowCountTitleOne": r"1 item selected",
+    "selectedRowCountTitleOther": r"$selectedRowCount items selected",
+    "cancelButtonLabel": r"CANCEL",
+    "closeButtonLabel": r"CLOSE",
+    "continueButtonLabel": r"CONTINUE",
+    "copyButtonLabel": r"COPY",
+    "cutButtonLabel": r"CUT",
     "okButtonLabel": r"OK",
-    "pasteButtonLabel": r"COLAR",
-    "selectAllButtonLabel": r"SELECIONAR TUDO",
-    "viewLicensesButtonLabel": r"VER LICENÇAS"
+    "pasteButtonLabel": r"PASTE",
+    "selectAllButtonLabel": r"SELECT ALL",
+    "viewLicensesButtonLabel": r"VIEW LICENSES",
+    "anteMeridiemAbbreviation": r"AM",
+    "postMeridiemAbbreviation": r"PM"
+  },
+  "en_GB": const <String, String>{
+    "timeOfDayFormat": r"HH:mm"
+  },
+  "en_IE": const <String, String>{
+    "timeOfDayFormat": r"HH:mm"
+  },
+  "en_ZA": const <String, String>{
+    "timeOfDayFormat": r"HH:mm"
   },
   "es": const <String, String>{
+    "timeOfDayFormat": r"H:mm",
     "openAppDrawerTooltip": r"Abrir el menú de navegación",
     "backButtonTooltip": r"Espalda",
     "closeButtonTooltip": r"Cerrar",
@@ -229,7 +130,36 @@ const Map<String, Map<String, String>> localizations = const <String, Map<String
     "selectAllButtonLabel": r"SELECCIONAR TODO",
     "viewLicensesButtonLabel": r"VER LICENCIAS"
   },
+  "es_US": const <String, String>{
+    "timeOfDayFormat": r"h:mm a"
+  },
+  "fa": const <String, String>{
+    "timeOfDayFormat": r"H:mm",
+    "openAppDrawerTooltip": r"منوی ناوبری را باز کنید",
+    "backButtonTooltip": r"بازگشت",
+    "closeButtonTooltip": r"بستن",
+    "nextMonthTooltip": r"ماه بعد",
+    "previousMonthTooltip": r"ماه گذشته",
+    "nextPageTooltip": r"صفحه بعد",
+    "previousPageTooltip": r"صفحه قبلی",
+    "showMenuTooltip": r"نمایش منو",
+    "licensesPageTitle": r"مجوز",
+    "pageRowsInfoTitle": r"$firstRow–$lastRow از $rowCount",
+    "pageRowsInfoTitleApproximate": r"$firstRow–$lastRow از حدود $rowCount",
+    "rowsPerPageTitle": r"ردیف در صفحه:",
+    "selectedRowCountTitleOther": r"$selectedRowCount آیتم های انتخاب شده",
+    "cancelButtonLabel": r"لغو",
+    "closeButtonLabel": r"بستن",
+    "continueButtonLabel": r"ادامه دهید",
+    "copyButtonLabel": r"کپی",
+    "cutButtonLabel": r"برش",
+    "okButtonLabel": r"تایید",
+    "pasteButtonLabel": r"چسباندن",
+    "selectAllButtonLabel": r"انتخاب همه",
+    "viewLicensesButtonLabel": r"مشاهده مجوز"
+  },
   "fr": const <String, String>{
+    "timeOfDayFormat": r"HH:mm",
     "openAppDrawerTooltip": r"Ouvrir le menu de navigation",
     "backButtonTooltip": r"Retour",
     "closeButtonTooltip": r"Fermer",
@@ -255,83 +185,61 @@ const Map<String, Map<String, String>> localizations = const <String, Map<String
     "selectAllButtonLabel": r"TOUT SÉLECTIONNER",
     "viewLicensesButtonLabel": r"AFFICHER LES LICENCES"
   },
-  "zh": const <String, String>{
-    "openAppDrawerTooltip": r"打开导航菜单",
-    "backButtonTooltip": r"返回",
-    "closeButtonTooltip": r"关闭",
-    "nextMonthTooltip": r"下一个月",
-    "previousMonthTooltip": r"上一个月",
-    "nextPageTooltip": r"下一页",
-    "previousPageTooltip": r"上一页",
-    "showMenuTooltip": r"显示菜单",
-    "licensesPageTitle": r"许可证",
-    "pageRowsInfoTitle": r"$rowCount中的$firstRow-$lastRow",
-    "pageRowsInfoTitleApproximate": r"约$rowCount中的$firstRow-$lastRow",
-    "rowsPerPageTitle": r"每页行数：",
-    "selectedRowCountTitleOther": r"$selectedRowCount行所选",
-    "cancelButtonLabel": r"取消",
-    "continueButtonLabel": r"继续",
-    "closeButtonLabel": r"关闭",
-    "copyButtonLabel": r"复制",
-    "cutButtonLabel": r"剪切",
-    "okButtonLabel": r"确定",
-    "pasteButtonLabel": r"粘贴",
-    "selectAllButtonLabel": r"全选",
-    "viewLicensesButtonLabel": r"查看许可证"
+  "fr_CA": const <String, String>{
+    "timeOfDayFormat": r"HH 'h' mm"
   },
-  "en": const <String, String>{
-    "openAppDrawerTooltip": r"Open navigation menu",
-    "backButtonTooltip": r"Back",
-    "closeButtonTooltip": r"Close",
-    "nextMonthTooltip": r"Next month",
-    "previousMonthTooltip": r"Previous month",
-    "nextPageTooltip": r"Next page",
-    "previousPageTooltip": r"Previous page",
-    "showMenuTooltip": r"Show menu",
-    "licensesPageTitle": r"Licenses",
-    "pageRowsInfoTitle": r"$firstRow–$lastRow of $rowCount",
-    "pageRowsInfoTitleApproximate": r"$firstRow–$lastRow of about $rowCount",
-    "rowsPerPageTitle": r"Rows per page:",
-    "selectedRowCountTitleZero": r"No items selected",
-    "selectedRowCountTitleOne": r"1 item selected",
-    "selectedRowCountTitleOther": r"$selectedRowCount items selected",
-    "cancelButtonLabel": r"CANCEL",
-    "closeButtonLabel": r"CLOSE",
-    "continueButtonLabel": r"CONTINUE",
-    "copyButtonLabel": r"COPY",
-    "cutButtonLabel": r"CUT",
-    "okButtonLabel": r"OK",
-    "pasteButtonLabel": r"PASTE",
-    "selectAllButtonLabel": r"SELECT ALL",
-    "viewLicensesButtonLabel": r"VIEW LICENSES"
+  "he": const <String, String>{
+    "timeOfDayFormat": r"H:mm",
+    "openAppDrawerTooltip": r"פתח תפריט ניווט",
+    "backButtonTooltip": r"אחורה",
+    "closeButtonTooltip": r"סגור",
+    "nextMonthTooltip": r"חודש הבא",
+    "previousMonthTooltip": r"חודש שעבר",
+    "nextPageTooltip": r"עמוד הבא",
+    "previousPageTooltip": r"עמוד קודם",
+    "showMenuTooltip": r"הצג תפריט",
+    "licensesPageTitle": r"רישיונות",
+    "pageRowsInfoTitle": r"$firstRow–$lastRow מתוך $rowCount",
+    "pageRowsInfoTitleApproximate": r"$firstRow–$lastRow מתוך כ $rowCount",
+    "rowsPerPageTitle": r"שורות לעמוד:",
+    "selectedRowCountTitleOther": r"$selectedRowCount פריטים שנבחרו",
+    "cancelButtonLabel": r"ביטול",
+    "closeButtonLabel": r"סגור",
+    "continueButtonLabel": r"לְהַמשִׁיך",
+    "copyButtonLabel": r"קיבלתי!",
+    "cutButtonLabel": r"גזור",
+    "okButtonLabel": r"בסדר",
+    "pasteButtonLabel": r"הדבק",
+    "selectAllButtonLabel": r"בחר הכל",
+    "viewLicensesButtonLabel": r"ראה רישיונות"
   },
-  "de": const <String, String>{
-    "openAppDrawerTooltip": r"Navigationsmenü öffnen",
-    "backButtonTooltip": r"Zurück",
-    "closeButtonTooltip": r"Schließen",
-    "nextMonthTooltip": r"Nächster Monat",
-    "previousMonthTooltip": r"Vorheriger Monat",
-    "nextPageTooltip": r"Nächste Seite",
-    "previousPageTooltip": r"Vorherige Seite",
-    "showMenuTooltip": r"Menü anzeigen",
-    "licensesPageTitle": r"Lizenzen",
-    "pageRowsInfoTitle": r"$firstRow–$lastRow von $rowCount",
-    "pageRowsInfoTitleApproximate": r"$firstRow–$lastRow von etwa $rowCount",
-    "rowsPerPageTitle": r"Zeilen pro Seite:",
-    "selectedRowCountTitleZero": r"Keine Objekte ausgewählt",
-    "selectedRowCountTitleOne": r"1 Objekt ausgewählt",
-    "selectedRowCountTitleOther": r"$selectedRowCount Objekte ausgewählt",
-    "cancelButtonLabel": r"ABBRECHEN",
-    "closeButtonLabel": r"SCHLIESSEN",
-    "continueButtonLabel": r"FORTSETZEN",
-    "copyButtonLabel": r"KOPIEREN",
-    "cutButtonLabel": r"AUSSCHNEIDEN",
+  "it": const <String, String>{
+    "timeOfDayFormat": r"HH:mm",
+    "openAppDrawerTooltip": r"Apri il menu di navigazione",
+    "backButtonTooltip": r"Indietro",
+    "closeButtonTooltip": r"Chiudi",
+    "nextMonthTooltip": r"Il prossimo mese",
+    "previousMonthTooltip": r"Il mese scorso",
+    "nextPageTooltip": r"Pagina successiva",
+    "previousPageTooltip": r"Pagina precedente",
+    "showMenuTooltip": r"Mostra il menu",
+    "licensesPageTitle": r"Licenze",
+    "pageRowsInfoTitle": r"$firstRow–$lastRow di $rowCount",
+    "pageRowsInfoTitleApproximate": r"$firstRow–$lastRow di circa $rowCount",
+    "rowsPerPageTitle": r"Righe per pagina:",
+    "selectedRowCountTitleOther": r"$selectedRowCount selezionati",
+    "cancelButtonLabel": r"ANNULLA",
+    "closeButtonLabel": r"CHIUDI",
+    "continueButtonLabel": r"CONTINUA",
+    "copyButtonLabel": r"COPY",
+    "cutButtonLabel": r"TAGLIARE",
     "okButtonLabel": r"OK",
-    "pasteButtonLabel": r"EINFÜGEN",
-    "selectAllButtonLabel": r"ALLES AUSWÄHLEN",
-    "viewLicensesButtonLabel": r"LIZENZEN ANZEIGEN"
+    "pasteButtonLabel": r"INCOLLA",
+    "selectAllButtonLabel": r"SELEZIONA TUTTO",
+    "viewLicensesButtonLabel": r"VEDI LE LICENZE"
   },
   "ja": const <String, String>{
+    "timeOfDayFormat": r"H:mm",
     "openAppDrawerTooltip": r"ナビゲーションメニューを開く",
     "backButtonTooltip": r"戻る",
     "closeButtonTooltip": r"閉じる",
@@ -355,7 +263,58 @@ const Map<String, Map<String, String>> localizations = const <String, Map<String
     "selectAllButtonLabel": r"全選択",
     "viewLicensesButtonLabel": r"ライセンス表記"
   },
+  "ps": const <String, String>{
+    "timeOfDayFormat": r"HH:mm",
+    "openAppDrawerTooltip": r"د پرانیستی نیینګ مینو",
+    "backButtonTooltip": r"شاته",
+    "closeButtonTooltip": r"بنده",
+    "nextMonthTooltip": r"بله میاشت",
+    "previousMonthTooltip": r"تیره میاشت",
+    "nextPageTooltip": r"بله پاڼه",
+    "previousPageTooltip": r"مخکینی مخ",
+    "showMenuTooltip": r"غورنۍ ښودل",
+    "licensesPageTitle": r"جوازونه",
+    "pageRowsInfoTitle": r"$firstRow–$lastRow د $rowCount",
+    "pageRowsInfoTitleApproximate": r"$firstRow–$lastRow څخه $rowCount د",
+    "rowsPerPageTitle": r"د هرې پاڼې پاڼې:",
+    "selectedRowCountTitleOther": r"$selectedRowCount توکي غوره شوي",
+    "cancelButtonLabel": r"لغوه کول",
+    "closeButtonLabel": r"تړل",
+    "continueButtonLabel": r"منځپانګې",
+    "copyButtonLabel": r"کاپی",
+    "cutButtonLabel": r"کم کړئ",
+    "okButtonLabel": r"سمه ده",
+    "pasteButtonLabel": r"پیټ کړئ",
+    "selectAllButtonLabel": r"غوره کړئ",
+    "viewLicensesButtonLabel": r"لیدلس وګورئ"
+  },
+  "pt": const <String, String>{
+    "timeOfDayFormat": r"HH:mm",
+    "openAppDrawerTooltip": r"Abrir menu de navegação",
+    "backButtonTooltip": r"Costas",
+    "closeButtonTooltip": r"Fechar",
+    "nextMonthTooltip": r"Próximo mês",
+    "previousMonthTooltip": r"Mês anterior",
+    "nextPageTooltip": r"Próxima página",
+    "previousPageTooltip": r"Página anterior",
+    "showMenuTooltip": r"Mostrar menu",
+    "licensesPageTitle": r"Licenças",
+    "pageRowsInfoTitle": r"$firstRow–$lastRow de $rowCount",
+    "pageRowsInfoTitleApproximate": r"$firstRow–$lastRow de cerca de $rowCount",
+    "rowsPerPageTitle": r"Linhas por página:",
+    "selectedRowCountTitleOther": r"$selectedRowCount selecionados",
+    "cancelButtonLabel": r"CANCELAR",
+    "closeButtonLabel": r"FECHAR",
+    "continueButtonLabel": r"CONTINUAR",
+    "copyButtonLabel": r"CÓPIA DE",
+    "cutButtonLabel": r"CORTA",
+    "okButtonLabel": r"OK",
+    "pasteButtonLabel": r"COLAR",
+    "selectAllButtonLabel": r"SELECIONAR TUDO",
+    "viewLicensesButtonLabel": r"VER LICENÇAS"
+  },
   "ru": const <String, String>{
+    "timeOfDayFormat": r"H:mm",
     "openAppDrawerTooltip": r"Открыть меню навигации",
     "backButtonTooltip": r"назад",
     "closeButtonTooltip": r"Закрыть",
@@ -378,5 +337,85 @@ const Map<String, Map<String, String>> localizations = const <String, Map<String
     "pasteButtonLabel": r"Паст",
     "selectAllButtonLabel": r"Выбрать все",
     "viewLicensesButtonLabel": r"ПРОСМОТРЕТЬ ЛИЦЕНЗИИ"
+  },
+  "sd": const <String, String>{
+    "timeOfDayFormat": r"HH:mm",
+    "openAppDrawerTooltip": r"اوپن جي مينڊيٽ مينيو",
+    "backButtonTooltip": r"پوئتي",
+    "closeButtonTooltip": r"بند ڪريو",
+    "nextMonthTooltip": r"ايندڙ مهيني",
+    "previousMonthTooltip": r"پويون مهينو",
+    "nextPageTooltip": r"اڳيون پيج",
+    "previousPageTooltip": r"پويون صفحو",
+    "showMenuTooltip": r"ڏيکاريو",
+    "licensesPageTitle": r"لائسنس",
+    "pageRowsInfoTitle": r"$firstRow–$lastRow جي $rowCount",
+    "pageRowsInfoTitleApproximate": r"$firstRow–$lastRow کان $rowCount تقريبن",
+    "rowsPerPageTitle": r"رني پاسي وارو صفحو",
+    "selectedRowCountTitleOther": r"$selectedRowCount شيون چونڊيل",
+    "cancelButtonLabel": r"منسوخ ڪيو",
+    "closeButtonLabel": r"بند ڪريو",
+    "continueButtonLabel": r"جاري رکو",
+    "copyButtonLabel": r"ڪاپي",
+    "cutButtonLabel": r"پٽي",
+    "okButtonLabel": r"ٺيڪ آهي",
+    "pasteButtonLabel": r"پيسٽ ڪريو",
+    "selectAllButtonLabel": r"سڀ چونڊيو",
+    "viewLicensesButtonLabel": r"لائسنس ڏسو"
+  },
+  "ur": const <String, String>{
+    "timeOfDayFormat": r"h:mm a",
+    "openAppDrawerTooltip": r"کھولیں نیویگیشن مینو",
+    "backButtonTooltip": r"واپس",
+    "closeButtonTooltip": r"بند کریں",
+    "nextMonthTooltip": r"اگلا مھینہ",
+    "previousMonthTooltip": r"پچھلا مھینہ",
+    "nextPageTooltip": r"اگلا صفحہ",
+    "previousPageTooltip": r"سابقہ ​​صفحہ",
+    "showMenuTooltip": r"مینو دکھائیں",
+    "licensesPageTitle": r"لائسنس",
+    "pageRowsInfoTitle": r"$firstRow–$lastRow کے $rowCount",
+    "pageRowsInfoTitleApproximate": r"$firstRow–$lastRow میں سے $rowCount تقریبا",
+    "rowsPerPageTitle": r"رویوں فی صفحہ:",
+    "selectedRowCountTitleOther": r"$selectedRowCount منتخب کردہ اشیاء",
+    "cancelButtonLabel": r"منسوخ کریں",
+    "closeButtonLabel": r"بند کریں",
+    "continueButtonLabel": r"جاری رکھیں",
+    "copyButtonLabel": r"کاپی",
+    "cutButtonLabel": r"کاٹیں",
+    "okButtonLabel": r"ٹھیک ہے",
+    "pasteButtonLabel": r"چسپاں",
+    "selectAllButtonLabel": r"تکاپیمام منتخب کریں",
+    "viewLicensesButtonLabel": r"لائسنس دیکھیں",
+    "anteMeridiemAbbreviation": r"AM",
+    "postMeridiemAbbreviation": r"PM"
+  },
+  "zh": const <String, String>{
+    "timeOfDayFormat": r"ah:mm",
+    "openAppDrawerTooltip": r"打开导航菜单",
+    "backButtonTooltip": r"背部",
+    "closeButtonTooltip": r"关",
+    "nextMonthTooltip": r"-下月就29了。",
+    "previousMonthTooltip": r"前一个月",
+    "nextPageTooltip": r"下一页",
+    "previousPageTooltip": r"上一页",
+    "showMenuTooltip": r"显示菜单",
+    "licensesPageTitle": r"许可证",
+    "pageRowsInfoTitle": r"$rowCount中的$firstRow-$lastRow",
+    "pageRowsInfoTitleApproximate": r"约$rowCount中的$firstRow-$lastRow",
+    "rowsPerPageTitle": r"每页行数：",
+    "selectedRowCountTitleOther": r"$selectedRowCount行所选",
+    "cancelButtonLabel": r"取消",
+    "continueButtonLabel": r"继续",
+    "closeButtonLabel": r"关闭",
+    "copyButtonLabel": r"复制",
+    "cutButtonLabel": r"剪切",
+    "okButtonLabel": r"确定",
+    "pasteButtonLabel": r"粘贴",
+    "selectAllButtonLabel": r"全选",
+    "viewLicensesButtonLabel": r"查看许可证",
+    "anteMeridiemAbbreviation": r"上午",
+    "postMeridiemAbbreviation": r"下午"
   }
 };
+

packages/flutter/lib/src/material/i18n/material_ar.arb

 {
+  "timeOfDayFormat": "h:mm a",
   "openAppDrawerTooltip": "افتح قائمة التنقل",
   "backButtonTooltip": "الى الخلف",
   "closeButtonTooltip": "إغلا",
@@ -20,5 +21,7 @@
   "okButtonLabel": "حسنا",
   "pasteButtonLabel": "عجين",
   "selectAllButtonLabel": "اختر الكل",
-  "viewLicensesButtonLabel": "عرض التراخيص"
+  "viewLicensesButtonLabel": "عرض التراخيص",
+  "anteMeridiemAbbreviation": "ص",
+  "postMeridiemAbbreviation": "م"
 }

packages/flutter/lib/src/material/i18n/material_de.arb

 {
+  "timeOfDayFormat": "HH:mm",
   "openAppDrawerTooltip": "Navigationsmenü öffnen",
   "backButtonTooltip": "Zurück",
   "closeButtonTooltip": "Schließen",

packages/flutter/lib/src/material/i18n/material_en.arb

 {
+  "timeOfDayFormat": "h:mm a",
+  "@timeOfDayFormat": {
+    "description": "The ICU 'Short Time' pattern, such as 'HH:mm', 'h:mm a', 'H:mm'. See: http://demo.icu-project.org/icu-bin/locexp?d_=en&_=en_US",
+    "type": "text"
+  },
+
   "openAppDrawerTooltip": "Open navigation menu",
   "@openAppDrawerTooltip": {
     "description": "The tooltip for the leading AppBar menu (aka 'hamburger') button",
@@ -126,5 +132,17 @@
   "@viewLicensesButtonLabel": {
     "description": "The label for the about box's view licenses button.",
     "type": "text"
+  },
+
+  "anteMeridiemAbbreviation": "AM",
+  "@anteMeridiemAbbreviation": {
+    "description": "The abbreviation for ante meridiem (before noon) shown in the time picker.",
+    "type": "text"
+  },
+
+  "postMeridiemAbbreviation": "PM",
+  "@postMeridiemAbbreviation": {
+    "description": "The abbreviation for post meridiem (after noon) shown in the time picker.",
+    "type": "text"
   }
 }

packages/flutter/lib/src/material/i18n/material_en_GB.arb

+{
+  "timeOfDayFormat": "HH:mm"
+}

packages/flutter/lib/src/material/i18n/material_en_IE.arb

+{
+  "timeOfDayFormat": "HH:mm"
+}

packages/flutter/lib/src/material/i18n/material_en_ZA.arb

+{
+  "timeOfDayFormat": "HH:mm"
+}

packages/flutter/lib/src/material/i18n/material_es.arb

 {
+  "timeOfDayFormat": "H:mm",
   "openAppDrawerTooltip": "Abrir el menú de navegación",
   "backButtonTooltip": "Espalda",
   "closeButtonTooltip": "Cerrar",

packages/flutter/lib/src/material/i18n/material_es_US.arb

+{
+  "timeOfDayFormat": "h:mm a"
+}

packages/flutter/lib/src/material/i18n/material_fa.arb

 {
+  "timeOfDayFormat": "H:mm",
   "openAppDrawerTooltip": "منوی ناوبری را باز کنید",
   "backButtonTooltip": "بازگشت",
   "closeButtonTooltip": "بستن",

packages/flutter/lib/src/material/i18n/material_fr.arb

 {
+  "timeOfDayFormat": "HH:mm",
   "openAppDrawerTooltip": "Ouvrir le menu de navigation",
   "backButtonTooltip": "Retour",
   "closeButtonTooltip": "Fermer",

packages/flutter/lib/src/material/i18n/material_fr_CA.arb

+{
+  "timeOfDayFormat": "HH 'h' mm"
+}

packages/flutter/lib/src/material/i18n/material_he.arb

 {
+  "timeOfDayFormat": "H:mm",
   "openAppDrawerTooltip": "פתח תפריט ניווט",
   "backButtonTooltip": "אחורה",
   "closeButtonTooltip": "סגור",

packages/flutter/lib/src/material/i18n/material_it.arb

 {
+  "timeOfDayFormat": "HH:mm",
   "openAppDrawerTooltip": "Apri il menu di navigazione",
   "backButtonTooltip": "Indietro",
   "closeButtonTooltip": "Chiudi",

packages/flutter/lib/src/material/i18n/material_ja.arb

 {
+  "timeOfDayFormat": "H:mm",
   "openAppDrawerTooltip": "ナビゲーションメニューを開く",
   "backButtonTooltip": "戻る",
   "closeButtonTooltip": "閉じる",

packages/flutter/lib/src/material/i18n/material_ps.arb

 {
+  "timeOfDayFormat": "HH:mm",
   "openAppDrawerTooltip": "د پرانیستی نیینګ مینو",
   "backButtonTooltip": "شاته",
   "closeButtonTooltip": "بنده",

packages/flutter/lib/src/material/i18n/material_pt.arb

 {
+  "timeOfDayFormat": "HH:mm",
   "openAppDrawerTooltip": "Abrir menu de navegação",
   "backButtonTooltip": "Costas",
   "closeButtonTooltip": "Fechar",

packages/flutter/lib/src/material/i18n/material_ru.arb

 {
+  "timeOfDayFormat": "H:mm",
   "openAppDrawerTooltip": "Открыть меню навигации",
   "backButtonTooltip": "назад",
   "closeButtonTooltip": "Закрыть",

packages/flutter/lib/src/material/i18n/material_sd.arb

 {
+  "timeOfDayFormat": "HH:mm",
   "openAppDrawerTooltip": "اوپن جي مينڊيٽ مينيو",
   "backButtonTooltip": "پوئتي",
   "closeButtonTooltip": "بند ڪريو",

packages/flutter/lib/src/material/i18n/material_ur.arb

 {
+  "timeOfDayFormat": "h:mm a",
   "openAppDrawerTooltip": "کھولیں نیویگیشن مینو",
   "backButtonTooltip": "واپس",
   "closeButtonTooltip": "بند کریں",
@@ -20,5 +21,7 @@
   "okButtonLabel": "ٹھیک ہے",
   "pasteButtonLabel": "چسپاں",
   "selectAllButtonLabel": "تکاپیمام منتخب کریں",
-  "viewLicensesButtonLabel": "لائسنس دیکھیں"
+  "viewLicensesButtonLabel": "لائسنس دیکھیں",
+  "anteMeridiemAbbreviation": "AM",
+  "postMeridiemAbbreviation": "PM"
 }
\ No newline at end of file

packages/flutter/lib/src/material/i18n/material_zh.arb

 {
+  "timeOfDayFormat": "ah:mm",
   "openAppDrawerTooltip": "打开导航菜单",
   "backButtonTooltip": "返回",
   "closeButtonTooltip": "关闭",
@@ -20,5 +21,11 @@
   "okButtonLabel": "确定",
   "pasteButtonLabel": "粘贴",
   "selectAllButtonLabel": "全选",
-  "viewLicensesButtonLabel": "查看许可证"
+  "viewLicensesButtonLabel": "查看许可证",
+  "backButtonTooltip": "背部",
+  "closeButtonTooltip": "关",
+  "nextMonthTooltip": "-下月就29了。",
+  "previousMonthTooltip": "前一个月",
+  "anteMeridiemAbbreviation": "上午",
+  "postMeridiemAbbreviation": "下午"
 }

packages/flutter/lib/src/material/material_localizations.dart

@@ -10,7 +10,7 @@ import 'package:intl/intl.dart' as intl;
 
 import 'i18n/localizations.dart';
 
-/// Defines the localized resource values used by the Material widgts.
+/// Defines the localized resource values used by the Material widgets.
 ///
 /// See also:
 ///
@@ -80,6 +80,18 @@ abstract class MaterialLocalizations {
   /// Label for the [AboutBox] 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;
+
   /// The `MaterialLocalizations` from the closest [Localizations] instance
   /// that encloses the given context.
   ///
@@ -99,25 +111,30 @@ abstract class MaterialLocalizations {
 
 /// Localized strings for the material widgets.
 class DefaultMaterialLocalizations implements MaterialLocalizations {
-  /// Construct an object that defines the material widgets' localized strings
+  /// 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) {
+  factory DefaultMaterialLocalizations(Locale locale) {
     assert(locale != null);
-    _nameToValue = localizations[_localeName]
-      ?? localizations[locale.languageCode]
-      ?? localizations['en']
-      ?? <String, String>{};
+
+    final Map<String, String> result = <String, String>{};
+    if (localizations.containsKey(locale.languageCode))
+      result.addAll(localizations[locale.languageCode]);
+    if (localizations.containsKey(locale.toString()))
+      result.addAll(localizations[locale.toString()]);
+    return new DefaultMaterialLocalizations._(locale, result);
   }
 
-  Map<String, String> _nameToValue;
+  DefaultMaterialLocalizations._(this.locale, this._nameToValue);
 
   /// The locale for which the values of this class's localized resources
   /// have been translated.
   final Locale locale;
 
+  final Map<String, String> _nameToValue;
+
   String get _localeName {
     final String localeName = locale.countryCode.isEmpty ? locale.languageCode : locale.toString();
     return intl.Intl.canonicalizedLocale(localeName);
@@ -224,6 +241,47 @@ class DefaultMaterialLocalizations implements MaterialLocalizations {
   @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];
+  }
+
   /// Creates an object that provides localized resource values for the
   /// for the widgets of the material library.
   ///
@@ -233,3 +291,66 @@ class DefaultMaterialLocalizations implements MaterialLocalizations {
     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,
+};
+
+/// Determines how the time picker invoked using [showTimePicker] formats and
+/// lays out the time controls.
+///
+/// The time picker provides layout configurations optimized for each of the
+/// enum values.
+enum TimeOfDayFormat {
+  /// Corresponds to the ICU 'HH:mm' pattern.
+  ///
+  /// This format uses 24-hour two-digit zero-padded hours. Controls are always
+  /// laid out horizontally. Hours are separated from minutes by one colon
+  /// character.
+  HH_colon_mm,
+
+  /// Corresponds to the ICU 'HH.mm' pattern.
+  ///
+  /// This format uses 24-hour two-digit zero-padded hours. Controls are always
+  /// laid out horizontally. Hours are separated from minutes by one dot
+  /// character.
+  HH_dot_mm,
+
+  /// Corresponds to the ICU "HH 'h' mm" pattern used in Canadian French.
+  ///
+  /// This format uses 24-hour two-digit zero-padded hours. Controls are always
+  /// laid out horizontally. Hours are separated from minutes by letter 'h'.
+  frenchCanadian,
+
+  /// Corresponds to the ICU 'H:mm' pattern.
+  ///
+  /// This format uses 24-hour non-padded variable-length hours. Controls are
+  /// always laid out horizontally. Hours are separated from minutes by one
+  /// colon character.
+  H_colon_mm,
+
+  /// Corresponds to the ICU 'h:mm a' pattern.
+  ///
+  /// This format uses 12-hour non-padded variable-length hours with a day
+  /// period. Controls are laid out horizontally in portrait mode. In landscape
+  /// mode, the day period appears vertically after (consistent with the ambient
+  /// [TextDirection]) hour-minute indicator. Hours are separated from minutes
+  /// by one colon character.
+  h_colon_mm_space_a,
+
+  /// Corresponds to the ICU 'a h:mm' pattern.
+  ///
+  /// This format uses 12-hour non-padded variable-length hours with a day
+  /// period. Controls are laid out horizontally in portrait mode. In landscape
+  /// mode, the day period appears vertically before (consistent with the
+  /// ambient [TextDirection]) hour-minute indicator. Hours are separated from
+  /// minutes by one colon character.
+  a_space_h_colon_mm,
+}

packages/flutter/lib/src/material/time_picker.dart

@@ -35,7 +35,7 @@ enum DayPeriod {
   pm,
 }
 
-/// A value representing a time during the day
+/// A value representing a time during the day.
 @immutable
 class TimeOfDay {
   /// Creates a time of day.
@@ -89,16 +89,12 @@ class TimeOfDay {
 
   /// A string representing the hour of the current period (e.g., '4' or '6').
   String get hourOfPeriodLabel {
-    // TODO(ianh): Localize.
     final int hourOfPeriod = this.hourOfPeriod;
     if (hourOfPeriod == 0)
       return '12';
     return hourOfPeriod.toString();
   }
 
-  /// A string representing the current period (e.g., 'a.m.').
-  String get periodLabel => period == DayPeriod.am ? 'a.m.' : 'p.m.'; // TODO(ianh): Localize.
-
   /// The hour at which the current period starts.
   int get periodOffset => period == DayPeriod.am ? 0 : _kHoursPerPeriod;
 
@@ -114,9 +110,8 @@ class TimeOfDay {
   @override
   int get hashCode => hashValues(hour, minute);
 
-  // TODO(ianh): Localize.
   @override
-  String toString() => '$hourOfPeriodLabel:$minuteLabel $periodLabel';
+  String toString() => '$hourLabel:$minuteLabel';
 }
 
 enum _TimePickerMode { hour, minute }
@@ -130,84 +125,544 @@ const double _kTimePickerWidthLandscape = 512.0;
 const double _kTimePickerHeightPortrait = 484.0;
 const double _kTimePickerHeightLandscape = 304.0;
 
+/// The horizontal gap between the day period fragment and the fragment
+/// positioned next to it horizontally.
+///
+/// Normally there's only one horizontal sibling, and it may appear on the left
+/// or right depending on the current [TextDirection].
 const double _kPeriodGap = 8.0;
 
+/// The vertical gap between pieces when laid out vertically (in portrait mode).
+const double _kVerticalGap = 8.0;
+
 enum _TimePickerHeaderId {
   hour,
   colon,
   minute,
   period, // AM/PM picker
+  dot,
+  hString, // French Canadian "h" literal
+}
+
+/// Provides properties for rendering time picker header fragments.
+@immutable
+class _TimePickerFragmentContext {
+  const _TimePickerFragmentContext({
+    @required this.headerTextTheme,
+    @required this.textDirection,
+    @required this.selectedTime,
+    @required this.mode,
+    @required this.activeColor,
+    @required this.activeStyle,
+    @required this.inactiveColor,
+    @required this.inactiveStyle,
+    @required this.onTimeChange,
+    @required this.onModeChange,
+  }) : assert(headerTextTheme != null),
+       assert(textDirection != null),
+       assert(selectedTime != null),
+       assert(mode != null),
+       assert(activeColor != null),
+       assert(activeStyle != null),
+       assert(inactiveColor != null),
+       assert(inactiveStyle != null),
+       assert(onTimeChange != null),
+       assert(onModeChange != null);
+
+  final TextTheme headerTextTheme;
+  final TextDirection textDirection;
+  final TimeOfDay selectedTime;
+  final _TimePickerMode mode;
+  final Color activeColor;
+  final TextStyle activeStyle;
+  final Color inactiveColor;
+  final TextStyle inactiveStyle;
+  final ValueChanged<TimeOfDay> onTimeChange;
+  final ValueChanged<_TimePickerMode> onModeChange;
+}
+
+/// Describes how hours are formatted.
+enum _TimePickerHourFormat {
+  /// Zero-padded two-digit 24-hour format ranging from "00" to "23".
+  HH,
+
+  /// Non-padded variable-length 24-hour format ranging from "0" to "23".
+  H,
+
+  /// Non-padded variable-length hour in day period format ranging from "1" to
+  /// "12".
+  h,
+}
+
+/// Contains the [widget] and layout properties of an atom of time information,
+/// such as am/pm indicator, hour, minute and string literals appearing in the
+/// formatted time string.
+class _TimePickerHeaderFragment {
+  const _TimePickerHeaderFragment({
+    @required this.layoutId,
+    @required this.widget,
+    this.startMargin: 0.0,
+  }) : assert(layoutId != null),
+        assert(widget != null),
+        assert(startMargin != null);
+
+  /// Identifier used by the custom layout to refer to the widget.
+  final _TimePickerHeaderId layoutId;
+
+  /// The widget that renders a piece of time information.
+  final Widget widget;
+
+  /// Horizontal distance from the fragment appearing at the start of this
+  /// fragment.
+  ///
+  /// This value contributes to the total horizontal width of all fragments
+  /// appearing on the same line, unless it is the first fragment on the line,
+  /// in which case this value is ignored.
+  final double startMargin;
+}
+
+/// An unbreakable part of the time picker header.
+///
+/// When the picker is laid out vertically, [fragments] of the piece are laid
+/// out on the same line, with each piece getting its own line.
+class _TimePickerHeaderPiece {
+  /// Creates a time picker header piece.
+  ///
+  /// All arguments must be non-null. If the piece does not contain a pivot
+  /// fragment, use the value -1 as a convention.
+  const _TimePickerHeaderPiece(this.pivotIndex, this.fragments, { this.bottomMargin: 0.0 })
+      : assert(pivotIndex != null),
+        assert(fragments != null),
+        assert(bottomMargin != null);
+
+  /// Index into the [fragments] list, pointing at the fragment that's centered
+  /// horizontally.
+  final int pivotIndex;
+
+  /// Fragments this piece is made of.
+  final List<_TimePickerHeaderFragment> fragments;
+
+  /// Vertical distance between this piece and the next piece.
+  ///
+  /// This property applies only when the header is laid out vertically.
+  final double bottomMargin;
+}
+
+/// Describes how the time picker header must be formatted.
+///
+/// A [_TimePickerHeaderFormat] is made of multiple [_TimePickerHeaderPiece]s.
+/// A piece is made of multiple [_TimePickerHeaderFragment]s. A fragment has a
+/// widget used to render some time information and contains some layout
+/// properties.
+///
+/// ## Layout rules
+///
+/// Pieces are laid out such that all fragments inside the same piece are laid
+/// out horizontally. Pieces are laid out horizontally if portrait orientation,
+/// and vertically in landscape orientation.
+///
+/// One of the pieces is identified as a _centrepiece_. It is a piece that is
+/// positioned in the center of the header, with all other pieces positioned
+/// to the left or right of it.
+class _TimePickerHeaderFormat {
+  const _TimePickerHeaderFormat(this.centrepieceIndex, this.pieces)
+      : assert(centrepieceIndex != null),
+        assert(pieces != null);
+
+  /// Index into the [pieces] list pointing at the piece that contains the
+  /// pivot fragment.
+  final int centrepieceIndex;
+
+  /// Pieces that constitute a time picker header.
+  final List<_TimePickerHeaderPiece> pieces;
+}
+
+/// Displays the am/pm fragment and provides controls for switching between am
+/// and pm.
+class _DayPeriodControl extends StatelessWidget {
+  const _DayPeriodControl({
+    @required this.fragmentContext,
+  });
+
+  final _TimePickerFragmentContext fragmentContext;
+
+  void _handleChangeDayPeriod() {
+    final int newHour = (fragmentContext.selectedTime.hour + _kHoursPerPeriod) % _kHoursPerDay;
+    fragmentContext.onTimeChange(fragmentContext.selectedTime.replacing(hour: newHour));
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final MaterialLocalizations materialLocalizations = MaterialLocalizations.of(context);
+    final TextTheme headerTextTheme = fragmentContext.headerTextTheme;
+    final TimeOfDay selectedTime = fragmentContext.selectedTime;
+    final Color activeColor = fragmentContext.activeColor;
+    final Color inactiveColor = fragmentContext.inactiveColor;
+
+    final TextStyle amStyle = headerTextTheme.subhead.copyWith(
+        color: selectedTime.period == DayPeriod.am ? activeColor: inactiveColor
+    );
+    final TextStyle pmStyle = headerTextTheme.subhead.copyWith(
+        color: selectedTime.period == DayPeriod.pm ? activeColor: inactiveColor
+    );
+
+    return new GestureDetector(
+      onTap: Feedback.wrapForTap(_handleChangeDayPeriod, context),
+      behavior: HitTestBehavior.opaque,
+      child: new Column(
+        mainAxisSize: MainAxisSize.min,
+        children: <Widget>[
+          new Text(materialLocalizations.anteMeridiemAbbreviation, style: amStyle),
+          const SizedBox(width: 0.0, height: 4.0),  // Vertical spacer
+          new Text(materialLocalizations.postMeridiemAbbreviation, style: pmStyle),
+        ],
+      ),
+    );
+  }
+}
+
+/// Displays the hour fragment.
+///
+/// When tapped changes time picker dial mode to [_TimePickerMode.hour].
+class _HourControl extends StatelessWidget {
+  const _HourControl({
+    @required this.fragmentContext,
+    @required this.hourFormat,
+  });
+
+  final _TimePickerFragmentContext fragmentContext;
+  final _TimePickerHourFormat hourFormat;
+
+  @override
+  Widget build(BuildContext context) {
+    final TextStyle hourStyle = fragmentContext.mode == _TimePickerMode.hour
+        ? fragmentContext.activeStyle
+        : fragmentContext.inactiveStyle;
+
+    return new GestureDetector(
+      onTap: Feedback.wrapForTap(() => fragmentContext.onModeChange(_TimePickerMode.hour), context),
+      child: new Text(_formatHour(), style: hourStyle),
+    );
+  }
+
+  String _formatHour() {
+    assert(hourFormat != null);
+    switch (hourFormat) {
+      case _TimePickerHourFormat.HH:
+        return fragmentContext.selectedTime.hourLabel;
+      case _TimePickerHourFormat.H:
+        return fragmentContext.selectedTime.hour.toString();
+      case _TimePickerHourFormat.h:
+        return fragmentContext.selectedTime.hourOfPeriodLabel;
+    }
+    return null;
+  }
+}
+
+/// A passive fragment showing a string value.
+class _StringFragment extends StatelessWidget {
+  const _StringFragment({
+    @required this.fragmentContext,
+    @required this.value,
+  });
+
+  final _TimePickerFragmentContext fragmentContext;
+  final String value;
+
+  @override
+  Widget build(BuildContext context) {
+    return new Text(value, style: fragmentContext.inactiveStyle);
+  }
+}
+
+/// Displays the minute fragment.
+///
+/// When tapped changes time picker dial mode to [_TimePickerMode.minute].
+class _MinuteControl extends StatelessWidget {
+  const _MinuteControl({
+    @required this.fragmentContext,
+  });
+
+  final _TimePickerFragmentContext fragmentContext;
+
+  @override
+  Widget build(BuildContext context) {
+    final TextStyle minuteStyle = fragmentContext.mode == _TimePickerMode.minute
+        ? fragmentContext.activeStyle
+        : fragmentContext.inactiveStyle;
+
+    return new GestureDetector(
+      onTap: Feedback.wrapForTap(() => fragmentContext.onModeChange(_TimePickerMode.minute), context),
+      child: new Text(fragmentContext.selectedTime.minuteLabel, style: minuteStyle),
+    );
+  }
+}
+
+_TimePickerHourFormat _getHourFormat(TimeOfDayFormat format) {
+  switch (format) {
+    case TimeOfDayFormat.h_colon_mm_space_a:
+    case TimeOfDayFormat.a_space_h_colon_mm:
+      return _TimePickerHourFormat.h;
+    case TimeOfDayFormat.H_colon_mm:
+      return _TimePickerHourFormat.H;
+    case TimeOfDayFormat.HH_dot_mm:
+    case TimeOfDayFormat.HH_colon_mm:
+    case TimeOfDayFormat.frenchCanadian:
+      return _TimePickerHourFormat.HH;
+  }
+
+  return null;
+}
+
+/// Provides time picker header layout configuration for the given
+/// [timeOfDayFormat] passing [context] to each widget in the configuration.
+///
+/// [timeOfDayFormat] and [context] must not be `null`.
+_TimePickerHeaderFormat _buildHeaderFormat(TimeOfDayFormat timeOfDayFormat, _TimePickerFragmentContext context) {
+  // Creates an hour fragment.
+  _TimePickerHeaderFragment hour(_TimePickerHourFormat hourFormat) {
+    return new _TimePickerHeaderFragment(
+      layoutId: _TimePickerHeaderId.hour,
+      widget: new _HourControl(fragmentContext: context, hourFormat: hourFormat),
+      startMargin: _kPeriodGap,
+    );
+  }
+
+  // Creates a minute fragment.
+  _TimePickerHeaderFragment minute() {
+    return new _TimePickerHeaderFragment(
+      layoutId: _TimePickerHeaderId.minute,
+      widget: new _MinuteControl(fragmentContext: context),
+    );
+  }
+
+  // Creates a string fragment.
+  _TimePickerHeaderFragment string(_TimePickerHeaderId layoutId, String value) {
+    return new _TimePickerHeaderFragment(
+      layoutId: layoutId,
+      widget: new _StringFragment(
+        fragmentContext: context,
+        value: value,
+      ),
+    );
+  }
+
+  // Creates an am/pm fragment.
+  _TimePickerHeaderFragment dayPeriod() {
+    return new _TimePickerHeaderFragment(
+      layoutId: _TimePickerHeaderId.period,
+      widget: new _DayPeriodControl(fragmentContext: context),
+      startMargin: _kPeriodGap,
+    );
+  }
+
+  // Convenience function for creating a time header format with up to two pieces.
+  _TimePickerHeaderFormat format(int centrepieceIndex, _TimePickerHeaderPiece piece1,
+      [ _TimePickerHeaderPiece piece2 ]) {
+    final List<_TimePickerHeaderPiece> pieces = <_TimePickerHeaderPiece>[];
+    switch (context.textDirection) {
+      case TextDirection.ltr:
+        pieces.add(piece1);
+        if (piece2 != null)
+          pieces.add(piece2);
+        break;
+      case TextDirection.rtl:
+        if (piece2 != null)
+          pieces.add(piece2);
+        pieces.add(piece1);
+        centrepieceIndex = pieces.length - centrepieceIndex - 1;
+        break;
+    }
+    return new _TimePickerHeaderFormat(centrepieceIndex, pieces);
+  }
+
+  // Convenience function for creating a time header piece with up to three fragments.
+  _TimePickerHeaderPiece piece({ int pivotIndex: -1, double bottomMargin: 0.0,
+      _TimePickerHeaderFragment fragment1, _TimePickerHeaderFragment fragment2, _TimePickerHeaderFragment fragment3 }) {
+    final List<_TimePickerHeaderFragment> fragments = <_TimePickerHeaderFragment>[fragment1];
+    if (fragment2 != null) {
+      fragments.add(fragment2);
+      if (fragment3 != null)
+        fragments.add(fragment3);
+    }
+    return new _TimePickerHeaderPiece(pivotIndex, fragments, bottomMargin: bottomMargin);
+  }
+
+  switch (timeOfDayFormat) {
+    case TimeOfDayFormat.h_colon_mm_space_a:
+      return format(
+        0,
+        piece(
+          pivotIndex: 1,
+          fragment1: hour(_TimePickerHourFormat.h),
+          fragment2: string(_TimePickerHeaderId.colon, ':'),
+          fragment3: minute(),
+        ),
+        piece(
+          bottomMargin: _kVerticalGap,
+          fragment1: dayPeriod(),
+        ),
+      );
+    case TimeOfDayFormat.H_colon_mm:
+      return format(0, piece(
+        pivotIndex: 1,
+        fragment1: hour(_TimePickerHourFormat.H),
+        fragment2: string(_TimePickerHeaderId.colon, ':'),
+        fragment3: minute(),
+      ));
+    case TimeOfDayFormat.HH_dot_mm:
+      return format(0, piece(
+        pivotIndex: 1,
+        fragment1: hour(_TimePickerHourFormat.HH),
+        fragment2: string(_TimePickerHeaderId.dot, '.'),
+        fragment3: minute(),
+      ));
+    case TimeOfDayFormat.a_space_h_colon_mm:
+      return format(
+        1,
+        piece(
+          bottomMargin: _kVerticalGap,
+          fragment1: dayPeriod(),
+        ),
+        piece(
+          pivotIndex: 1,
+          fragment1: hour(_TimePickerHourFormat.h),
+          fragment2: string(_TimePickerHeaderId.colon, ':'),
+          fragment3: minute(),
+        ),
+      );
+    case TimeOfDayFormat.frenchCanadian:
+      return format(0, piece(
+        pivotIndex: 1,
+        fragment1: hour(_TimePickerHourFormat.HH),
+        fragment2: string(_TimePickerHeaderId.hString, 'h'),
+        fragment3: minute(),
+      ));
+    case TimeOfDayFormat.HH_colon_mm:
+      return format(0, piece(
+        pivotIndex: 1,
+        fragment1: hour(_TimePickerHourFormat.HH),
+        fragment2: string(_TimePickerHeaderId.colon, ':'),
+        fragment3: minute(),
+      ));
+  }
+
+  return null;
 }
 
 class _TimePickerHeaderLayout extends MultiChildLayoutDelegate {
-  _TimePickerHeaderLayout(this.orientation);
+  _TimePickerHeaderLayout(this.orientation, this.format)
+    : assert(orientation != null),
+      assert(format != null);
 
   final Orientation orientation;
+  final _TimePickerHeaderFormat format;
 
   @override
   void performLayout(Size size) {
     final BoxConstraints constraints = new BoxConstraints.loose(size);
-    final Size hourSize = layoutChild(_TimePickerHeaderId.hour, constraints);
-    final Size colonSize = layoutChild(_TimePickerHeaderId.colon, constraints);
-    final Size minuteSize = layoutChild(_TimePickerHeaderId.minute, constraints);
-    final Size periodSize = layoutChild(_TimePickerHeaderId.period, constraints);
 
     switch (orientation) {
-      // 11:57--period
-      //
-      // The colon is centered horizontally, the entire layout is centered vertically.
-      // The "--" is a _kPeriodGap horizontal gap.
       case Orientation.portrait:
-        final double width = colonSize.width / 2.0 + minuteSize.width + _kPeriodGap + periodSize.width;
-        final double right = math.max(0.0, size.width / 2.0 - width);
+        _layoutHorizontally(size, constraints);
+        break;
+      case Orientation.landscape:
+        _layoutVertically(size, constraints);
+        break;
+    }
+  }
 
-        double x = size.width - right - periodSize.width;
-        positionChild(_TimePickerHeaderId.period, new Offset(x, (size.height - periodSize.height) / 2.0));
+  void _layoutHorizontally(Size size, BoxConstraints constraints) {
+    final List<_TimePickerHeaderFragment> fragmentsFlattened = <_TimePickerHeaderFragment>[];
+    final Map<_TimePickerHeaderId, Size> childSizes = <_TimePickerHeaderId, Size>{};
+    int pivotIndex = 0;
+    for (int pieceIndex = 0; pieceIndex < format.pieces.length; pieceIndex += 1) {
+      final _TimePickerHeaderPiece piece = format.pieces[pieceIndex];
+      for (final _TimePickerHeaderFragment fragment in piece.fragments) {
+        childSizes[fragment.layoutId] = layoutChild(fragment.layoutId, constraints);
+        fragmentsFlattened.add(fragment);
+      }
 
-        x -= minuteSize.width + _kPeriodGap;
-        positionChild(_TimePickerHeaderId.minute, new Offset(x, (size.height - minuteSize.height) / 2.0));
+      if (pieceIndex == format.centrepieceIndex)
+        pivotIndex += format.pieces[format.centrepieceIndex].pivotIndex;
+      else if (pieceIndex < format.centrepieceIndex)
+        pivotIndex += piece.fragments.length;
+    }
 
-        x -= colonSize.width;
-        positionChild(_TimePickerHeaderId.colon, new Offset(x, (size.height - colonSize.height) / 2.0));
+    _positionPivoted(size.width, size.height / 2.0, childSizes, fragmentsFlattened, pivotIndex);
+  }
 
-        x -= hourSize.width;
-        positionChild(_TimePickerHeaderId.hour, new Offset(x, (size.height - hourSize.height) / 2.0));
-      break;
+  void _layoutVertically(Size size, BoxConstraints constraints) {
+    final Map<_TimePickerHeaderId, Size> childSizes = <_TimePickerHeaderId, Size>{};
+    final List<double> pieceHeights = <double>[];
+    double height = 0.0;
+    double margin = 0.0;
+    for (final _TimePickerHeaderPiece piece in format.pieces) {
+      double pieceHeight = 0.0;
+      for (final _TimePickerHeaderFragment fragment in piece.fragments) {
+        final Size childSize = childSizes[fragment.layoutId] = layoutChild(fragment.layoutId, constraints);
+        pieceHeight = math.max(pieceHeight, childSize.height);
+      }
+      pieceHeights.add(pieceHeight);
+      height += pieceHeight + margin;
+      // Delay application of margin until next piece because margin of the
+      // bottom-most piece should not contribute to the size.
+      margin = piece.bottomMargin;
+    }
 
-      // 11:57
-      //  --
-      // period
-      //
-      // The colon is centered horizontally, the entire layout is centered vertically.
-      // The "--" is a _kPeriodGap vertical gap.
-      case Orientation.landscape:
-        final double width = colonSize.width / 2.0 + minuteSize.width;
-        final double offset = math.max(0.0, size.width / 2.0 - width);
-        final double timeHeight = math.max(hourSize.height, colonSize.height);
-        final double height = timeHeight + _kPeriodGap + periodSize.height;
-        final double timeCenter = (size.height - height) / 2.0 + timeHeight / 2.0;
+    final _TimePickerHeaderPiece centrepiece = format.pieces[format.centrepieceIndex];
+    double y = (size.height - height) / 2.0;
+    for (int pieceIndex = 0; pieceIndex < format.pieces.length; pieceIndex += 1) {
+      if (pieceIndex != format.centrepieceIndex)
+        _positionPiece(size.width, y, childSizes, format.pieces[pieceIndex].fragments);
+      else
+        _positionPivoted(size.width, y, childSizes, centrepiece.fragments, centrepiece.pivotIndex);
 
-        double x = size.width - offset - minuteSize.width;
-        positionChild(_TimePickerHeaderId.minute, new Offset(x, timeCenter - minuteSize.height / 2.0));
+      y += pieceHeights[pieceIndex] + format.pieces[pieceIndex].bottomMargin;
+    }
+  }
 
-        x -= colonSize.width;
-        positionChild(_TimePickerHeaderId.colon, new Offset(x, timeCenter - colonSize.height / 2.0));
+  void _positionPivoted(double width, double y, Map<_TimePickerHeaderId, Size> childSizes, List<_TimePickerHeaderFragment> fragments, int pivotIndex) {
+    double tailWidth = childSizes[fragments[pivotIndex].layoutId].width / 2.0;
+    for (_TimePickerHeaderFragment fragment in fragments.skip(pivotIndex + 1)) {
+      tailWidth += childSizes[fragment.layoutId].width + fragment.startMargin;
+    }
 
-        x -= hourSize.width;
-        positionChild(_TimePickerHeaderId.hour, new Offset(x, timeCenter - hourSize.height / 2.0));
+    double x = width / 2.0 + tailWidth;
+    x = math.min(x, width);
+    for (int i = fragments.length - 1; i >= 0; i -= 1) {
+      final _TimePickerHeaderFragment fragment = fragments[i];
+      final Size childSize = childSizes[fragment.layoutId];
+      x -= childSize.width;
+      positionChild(fragment.layoutId, new Offset(x, y - childSize.height / 2.0));
+      x -= fragment.startMargin;
+    }
+  }
 
-        x = (size.width - periodSize.width) / 2.0;
-        positionChild(_TimePickerHeaderId.period, new Offset(x, timeCenter + timeHeight / 2.0 + _kPeriodGap));
-        break;
+  void _positionPiece(double width, double centeredAroundY, Map<_TimePickerHeaderId, Size> childSizes, List<_TimePickerHeaderFragment> fragments) {
+    double pieceWidth = 0.0;
+    double nextMargin = 0.0;
+    for (_TimePickerHeaderFragment fragment in fragments) {
+      final Size childSize = childSizes[fragment.layoutId];
+      pieceWidth += childSize.width + nextMargin;
+      // Delay application of margin until next element because margin of the
+      // left-most fragment should not contribute to the size.
+      nextMargin = fragment.startMargin;
+    }
+    double x = (width + pieceWidth) / 2.0;
+    for (int i = fragments.length - 1; i >= 0; i -= 1) {
+      final _TimePickerHeaderFragment fragment = fragments[i];
+      final Size childSize = childSizes[fragment.layoutId];
+      x -= childSize.width;
+      positionChild(fragment.layoutId, new Offset(x, centeredAroundY - childSize.height / 2.0));
+      x -= fragment.startMargin;
     }
   }
 
   @override
-  bool shouldRelayout(_TimePickerHeaderLayout oldDelegate) => orientation != oldDelegate.orientation;
+  bool shouldRelayout(_TimePickerHeaderLayout oldDelegate) => orientation != oldDelegate.orientation || format != oldDelegate.format;
 }
 
-
-// TODO(ianh): Localize!
 class _TimePickerHeader extends StatelessWidget {
   const _TimePickerHeader({
     @required this.selectedTime,
@@ -230,11 +685,6 @@ class _TimePickerHeader extends StatelessWidget {
       onModeChanged(value);
   }
 
-  void _handleChangeDayPeriod() {
-    final int newHour = (selectedTime.hour + _kHoursPerPeriod) % _kHoursPerDay;
-    onChanged(selectedTime.replacing(hour: newHour));
-  }
-
   TextStyle _getBaseHeaderStyle(TextTheme headerTextTheme) {
     // These font sizes aren't listed in the spec explicitly. I worked them out
     // by measuring the text using a screen ruler and comparing them to the
@@ -252,18 +702,21 @@ class _TimePickerHeader extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     final ThemeData themeData = Theme.of(context);
-    final TextTheme headerTextTheme = themeData.primaryTextTheme;
-    final TextStyle baseHeaderStyle = _getBaseHeaderStyle(headerTextTheme);
-    Color activeColor;
-    Color inactiveColor;
-    switch(themeData.primaryColorBrightness) {
-      case Brightness.light:
-        activeColor = Colors.black87;
-        inactiveColor = Colors.black54;
+    final TimeOfDayFormat timeOfDayFormat = MaterialLocalizations.of(context).timeOfDayFormat;
+
+    EdgeInsets padding;
+    double height;
+    double width;
+
+    assert(orientation != null);
+    switch (orientation) {
+      case Orientation.portrait:
+        height = _kTimePickerHeaderPortraitHeight;
+        padding = const EdgeInsets.symmetric(horizontal: 24.0);
         break;
-      case Brightness.dark:
-        activeColor = Colors.white;
-        inactiveColor = Colors.white70;
+      case Orientation.landscape:
+        width = _kTimePickerHeaderLandscapeWidth;
+        padding = const EdgeInsets.symmetric(horizontal: 16.0);
         break;
     }
 
@@ -277,73 +730,52 @@ class _TimePickerHeader extends StatelessWidget {
         break;
     }
 
-    final TextStyle activeStyle = baseHeaderStyle.copyWith(color: activeColor);
-    final TextStyle inactiveStyle = baseHeaderStyle.copyWith(color: inactiveColor);
-
-    final TextStyle hourStyle = mode == _TimePickerMode.hour ? activeStyle : inactiveStyle;
-    final TextStyle minuteStyle = mode == _TimePickerMode.minute ? activeStyle : inactiveStyle;
-
-    final TextStyle amStyle = headerTextTheme.subhead.copyWith(
-      color: selectedTime.period == DayPeriod.am ? activeColor: inactiveColor
-    );
-    final TextStyle pmStyle = headerTextTheme.subhead.copyWith(
-      color: selectedTime.period == DayPeriod.pm ? activeColor: inactiveColor
-    );
-
-    final Widget dayPeriodPicker = new GestureDetector(
-      onTap: Feedback.wrapForTap(_handleChangeDayPeriod, context),
-      behavior: HitTestBehavior.opaque,
-      child: new Column(
-        mainAxisSize: MainAxisSize.min,
-        children: <Widget>[
-          new Text('AM', style: amStyle),
-          const SizedBox(width: 0.0, height: 4.0),  // Vertical spacer
-          new Text('PM', style: pmStyle),
-        ]
-      )
-    );
-
-    final Widget hour = new GestureDetector(
-      onTap: Feedback.wrapForTap(() => _handleChangeMode(_TimePickerMode.hour), context),
-      child: new Text(selectedTime.hourOfPeriodLabel, style: hourStyle),
-    );
-
-    final Widget minute = new GestureDetector(
-      onTap: Feedback.wrapForTap(() => _handleChangeMode(_TimePickerMode.minute), context),
-      child: new Text(selectedTime.minuteLabel, style: minuteStyle),
-    );
-
-    final Widget colon = new Text(':', style: inactiveStyle);
-
-    EdgeInsets padding;
-    double height;
-    double width;
-
-    assert(orientation != null);
-    switch(orientation) {
-      case Orientation.portrait:
-        height = _kTimePickerHeaderPortraitHeight;
-        padding = const EdgeInsets.symmetric(horizontal: 24.0);
+    Color activeColor;
+    Color inactiveColor;
+    switch (themeData.primaryColorBrightness) {
+      case Brightness.light:
+        activeColor = Colors.black87;
+        inactiveColor = Colors.black54;
         break;
-      case Orientation.landscape:
-        width = _kTimePickerHeaderLandscapeWidth;
-        padding = const EdgeInsets.symmetric(horizontal: 16.0);
+      case Brightness.dark:
+        activeColor = Colors.white;
+        inactiveColor = Colors.white70;
         break;
     }
 
+    final TextTheme headerTextTheme = themeData.primaryTextTheme;
+    final TextStyle baseHeaderStyle = _getBaseHeaderStyle(headerTextTheme);
+    final _TimePickerFragmentContext fragmentContext = new _TimePickerFragmentContext(
+      headerTextTheme: headerTextTheme,
+      textDirection: Directionality.of(context),
+      selectedTime: selectedTime,
+      mode: mode,
+      activeColor: activeColor,
+      activeStyle: baseHeaderStyle.copyWith(color: activeColor),
+      inactiveColor: inactiveColor,
+      inactiveStyle: baseHeaderStyle.copyWith(color: inactiveColor),
+      onTimeChange: onChanged,
+      onModeChange: _handleChangeMode,
+    );
+
+    final _TimePickerHeaderFormat format = _buildHeaderFormat(timeOfDayFormat, fragmentContext);
+
     return new Container(
       width: width,
       height: height,
       padding: padding,
       color: backgroundColor,
       child: new CustomMultiChildLayout(
-        delegate: new _TimePickerHeaderLayout(orientation),
-        children: <Widget>[
-          new LayoutId(id: _TimePickerHeaderId.hour, child: hour),
-          new LayoutId(id: _TimePickerHeaderId.colon, child: colon),
-          new LayoutId(id: _TimePickerHeaderId.minute, child: minute),
-          new LayoutId(id: _TimePickerHeaderId.period, child: dayPeriodPicker),
-        ],
+        delegate: new _TimePickerHeaderLayout(orientation, format),
+        children: format.pieces
+          .expand<_TimePickerHeaderFragment>((_TimePickerHeaderPiece piece) => piece.fragments)
+          .map<Widget>((_TimePickerHeaderFragment fragment) {
+            return new LayoutId(
+              id: fragment.layoutId,
+              child: fragment.widget,
+            );
+          })
+          .toList(),
       )
     );
   }
@@ -364,10 +796,25 @@ List<TextPainter> _initPainters(TextTheme textTheme, List<String> labels) {
   return painters;
 }
 
-List<TextPainter> _initHours(TextTheme textTheme) {
-  return _initPainters(textTheme, <String>[
+enum _DialRing {
+  outer,
+  inner,
+}
+
+List<TextPainter> _initHours(TextTheme textTheme, _DialRing ring, bool is24h) {
+  const List<String> amHours = const <String>[
     '12', '1', '2', '3', '4', '5', '6', '7', '8', '9', '10', '11'
-  ]);
+  ];
+  const List<String> pmHours = const <String>[
+    '00', '13', '14', '15', '16', '17', '18', '19', '20', '21', '22', '23'
+  ];
+  switch (ring) {
+    case _DialRing.outer:
+      return _initPainters(textTheme, is24h ? pmHours : amHours);
+    case _DialRing.inner:
+      return is24h ? _initPainters(textTheme, amHours) : null;
+  }
+  return null;
 }
 
 List<TextPainter> _initMinutes(TextTheme textTheme) {
@@ -378,18 +825,24 @@ List<TextPainter> _initMinutes(TextTheme textTheme) {
 
 class _DialPainter extends CustomPainter {
   const _DialPainter({
-    this.primaryLabels,
-    this.secondaryLabels,
-    this.backgroundColor,
-    this.accentColor,
-    this.theta
+    @required this.primaryOuterLabels,
+    @required this.primaryInnerLabels,
+    @required this.secondaryOuterLabels,
+    @required this.secondaryInnerLabels,
+    @required this.backgroundColor,
+    @required this.accentColor,
+    @required this.theta,
+    @required this.activeRing,
   });
 
-  final List<TextPainter> primaryLabels;
-  final List<TextPainter> secondaryLabels;
+  final List<TextPainter> primaryOuterLabels;
+  final List<TextPainter> primaryInnerLabels;
+  final List<TextPainter> secondaryOuterLabels;
+  final List<TextPainter> secondaryInnerLabels;
   final Color backgroundColor;
   final Color accentColor;
   final double theta;
+  final _DialRing activeRing;
 
   @override
   void paint(Canvas canvas, Size size) {
@@ -399,28 +852,41 @@ class _DialPainter extends CustomPainter {
     canvas.drawCircle(centerPoint, radius, new Paint()..color = backgroundColor);
 
     const double labelPadding = 24.0;
-    final double labelRadius = radius - labelPadding;
-    Offset getOffsetForTheta(double theta) {
+    final double outerLabelRadius = radius - labelPadding;
+    final double innerLabelRadius = radius - labelPadding * 2.5;
+    Offset getOffsetForTheta(double theta, _DialRing ring) {
+      double labelRadius;
+      switch (ring) {
+        case _DialRing.outer:
+          labelRadius = outerLabelRadius;
+          break;
+        case _DialRing.inner:
+          labelRadius = innerLabelRadius;
+          break;
+      }
       return center + new Offset(labelRadius * math.cos(theta),
                                  -labelRadius * math.sin(theta));
     }
 
-    void paintLabels(List<TextPainter> labels) {
+    void paintLabels(List<TextPainter> labels, _DialRing ring) {
+      if (labels == null)
+        return;
       final double labelThetaIncrement = -_kTwoPi / labels.length;
       double labelTheta = math.PI / 2.0;
 
       for (TextPainter label in labels) {
         final Offset labelOffset = new Offset(-label.width / 2.0, -label.height / 2.0);
-        label.paint(canvas, getOffsetForTheta(labelTheta) + labelOffset);
+        label.paint(canvas, getOffsetForTheta(labelTheta, ring) + labelOffset);
         labelTheta += labelThetaIncrement;
       }
     }
 
-    paintLabels(primaryLabels);
+    paintLabels(primaryOuterLabels, _DialRing.outer);
+    paintLabels(primaryInnerLabels, _DialRing.inner);
 
     final Paint selectorPaint = new Paint()
       ..color = accentColor;
-    final Offset focusedPoint = getOffsetForTheta(theta);
+    final Offset focusedPoint = getOffsetForTheta(theta, activeRing);
     final double focusedRadius = labelPadding - 4.0;
     canvas.drawCircle(centerPoint, 4.0, selectorPaint);
     canvas.drawCircle(focusedPoint, focusedRadius, selectorPaint);
@@ -433,17 +899,21 @@ class _DialPainter extends CustomPainter {
     canvas
       ..save()
       ..clipPath(new Path()..addOval(focusedRect));
-    paintLabels(secondaryLabels);
+    paintLabels(secondaryOuterLabels, _DialRing.outer);
+    paintLabels(secondaryInnerLabels, _DialRing.inner);
     canvas.restore();
   }
 
   @override
   bool shouldRepaint(_DialPainter oldPainter) {
-    return oldPainter.primaryLabels != primaryLabels
-        || oldPainter.secondaryLabels != secondaryLabels
+    return oldPainter.primaryOuterLabels != primaryOuterLabels
+        || oldPainter.primaryInnerLabels != primaryInnerLabels
+        || oldPainter.secondaryOuterLabels != secondaryOuterLabels
+        || oldPainter.secondaryInnerLabels != secondaryInnerLabels
         || oldPainter.backgroundColor != backgroundColor
         || oldPainter.accentColor != accentColor
-        || oldPainter.theta != theta;
+        || oldPainter.theta != theta
+        || oldPainter.activeRing != activeRing;
   }
 }
 
@@ -451,11 +921,13 @@ class _Dial extends StatefulWidget {
   const _Dial({
     @required this.selectedTime,
     @required this.mode,
+    @required this.is24h,
     @required this.onChanged
   }) : assert(selectedTime != null);
 
   final TimeOfDay selectedTime;
   final _TimePickerMode mode;
+  final bool is24h;
   final ValueChanged<TimeOfDay> onChanged;
 
   @override
@@ -480,9 +952,16 @@ class _DialState extends State<_Dial> with SingleTickerProviderStateMixin {
   @override
   void didUpdateWidget(_Dial oldWidget) {
     super.didUpdateWidget(oldWidget);
-    if (widget.mode != oldWidget.mode && !_dragging)
+    if (widget.mode != oldWidget.mode) {
+      if (!_dragging)
         _animateTo(_getThetaForTime(widget.selectedTime));
     }
+    if (widget.mode == _TimePickerMode.hour && widget.is24h && widget.selectedTime.period == DayPeriod.am) {
+      _activeRing = _DialRing.inner;
+    } else {
+      _activeRing = _DialRing.outer;
+    }
+  }
 
   @override
   void dispose() {
@@ -521,10 +1000,18 @@ class _DialState extends State<_Dial> with SingleTickerProviderStateMixin {
   TimeOfDay _getTimeForTheta(double theta) {
     final double fraction = (0.25 - (theta % _kTwoPi) / _kTwoPi) % 1.0;
     if (widget.mode == _TimePickerMode.hour) {
-      final int hourOfPeriod = (fraction * _kHoursPerPeriod).round() % _kHoursPerPeriod;
-      return widget.selectedTime.replacing(
-        hour: hourOfPeriod + widget.selectedTime.periodOffset
-      );
+      int newHour = (fraction * _kHoursPerPeriod).round() % _kHoursPerPeriod;
+      if (widget.is24h) {
+        if (_activeRing == _DialRing.outer) {
+          if (newHour != 0)
+            newHour = (newHour + _kHoursPerPeriod) % _kHoursPerDay;
+        } else if (newHour == 0) {
+          newHour = _kHoursPerPeriod;
+        }
+      } else {
+        newHour = newHour + widget.selectedTime.periodOffset;
+      }
+      return widget.selectedTime.replacing(hour: newHour);
     } else {
       return widget.selectedTime.replacing(
         minute: (fraction * _kMinutesPerHour).round() % _kMinutesPerHour
@@ -547,11 +1034,20 @@ class _DialState extends State<_Dial> with SingleTickerProviderStateMixin {
       _thetaTween
         ..begin = angle
         ..end = angle; // The controller doesn't animate during the pan gesture.
+      final RenderBox box = context.findRenderObject();
+      final double radius = box.size.shortestSide / 2.0;
+      if (widget.mode == _TimePickerMode.hour && widget.is24h) {
+        if (offset.distance * 1.5 < radius)
+          _activeRing = _DialRing.inner;
+        else
+          _activeRing = _DialRing.outer;
+      }
     });
   }
 
   Offset _position;
   Offset _center;
+  _DialRing _activeRing = _DialRing.outer;
 
   void _handlePanStart(DragStartDetails details) {
     assert(!_dragging);
@@ -592,16 +1088,22 @@ class _DialState extends State<_Dial> with SingleTickerProviderStateMixin {
     }
 
     final ThemeData theme = Theme.of(context);
-    List<TextPainter> primaryLabels;
-    List<TextPainter> secondaryLabels;
+    List<TextPainter> primaryOuterLabels;
+    List<TextPainter> primaryInnerLabels;
+    List<TextPainter> secondaryOuterLabels;
+    List<TextPainter> secondaryInnerLabels;
     switch (widget.mode) {
       case _TimePickerMode.hour:
-        primaryLabels = _initHours(theme.textTheme);
-        secondaryLabels = _initHours(theme.accentTextTheme);
+        primaryOuterLabels = _initHours(theme.textTheme, _DialRing.outer, widget.is24h);
+        secondaryOuterLabels = _initHours(theme.accentTextTheme, _DialRing.outer, widget.is24h);
+        primaryInnerLabels = _initHours(theme.textTheme, _DialRing.inner, widget.is24h);
+        secondaryInnerLabels = _initHours(theme.accentTextTheme, _DialRing.inner, widget.is24h);
         break;
       case _TimePickerMode.minute:
-        primaryLabels = _initMinutes(theme.textTheme);
-        secondaryLabels = _initMinutes(theme.accentTextTheme);
+        primaryOuterLabels = _initMinutes(theme.textTheme);
+        primaryInnerLabels = null;
+        secondaryOuterLabels = _initMinutes(theme.accentTextTheme);
+        secondaryInnerLabels = null;
         break;
     }
 
@@ -612,11 +1114,14 @@ class _DialState extends State<_Dial> with SingleTickerProviderStateMixin {
       child: new CustomPaint(
         key: const ValueKey<String>('time-picker-dial'), // used for testing.
         painter: new _DialPainter(
-          primaryLabels: primaryLabels,
-          secondaryLabels: secondaryLabels,
+          primaryOuterLabels: primaryOuterLabels,
+          primaryInnerLabels: primaryInnerLabels,
+          secondaryOuterLabels: secondaryOuterLabels,
+          secondaryInnerLabels: secondaryInnerLabels,
           backgroundColor: backgroundColor,
           accentColor: themeData.accentColor,
-          theta: _theta.value
+          theta: _theta.value,
+          activeRing: _activeRing,
         )
       )
     );
@@ -686,12 +1191,15 @@ class _TimePickerDialogState extends State<_TimePickerDialog> {
 
   @override
   Widget build(BuildContext context) {
+    final TimeOfDayFormat timeOfDayFormat = MaterialLocalizations.of(context).timeOfDayFormat;
+
     final Widget picker = new Padding(
       padding: const EdgeInsets.all(16.0),
       child: new AspectRatio(
         aspectRatio: 1.0,
         child: new _Dial(
           mode: _mode,
+          is24h: _getHourFormat(timeOfDayFormat) != _TimePickerHourFormat.h,
           selectedTime: _selectedTime,
           onChanged: _handleTimeChanged,
         )

packages/flutter/lib/src/widgets/viewport.dart

@@ -43,7 +43,7 @@ AxisDirection _getDefaultCrossAxisDirection(BuildContext context, AxisDirection
 /// example, if the [axisDirection] is [AxisDirection.down], the first sliver
 /// before [center] is placed above the [center]. The slivers that are later in
 /// the child list than [center] are placed in order in the [axisDirection]. For
-/// example, in the preceeding scenario, the first sliver after [center] is
+/// example, in the preceding scenario, the first sliver after [center] is
 /// placed below the [center].
 ///
 /// [Viewport] cannot contain box children directly. Instead, use a

packages/flutter/test/material/time_picker_test.dart

@@ -2,19 +2,24 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
+import 'package:flutter/rendering.dart';
+import 'package:flutter/widgets.dart';
 import 'package:flutter_test/flutter_test.dart';
 
 import 'feedback_tester.dart';
 
 class _TimePickerLauncher extends StatelessWidget {
-  const _TimePickerLauncher({ Key key, this.onChanged }) : super(key: key);
+  const _TimePickerLauncher({ Key key, this.onChanged, this.locale }) : super(key: key);
 
   final ValueChanged<TimeOfDay> onChanged;
+  final Locale locale;
 
   @override
   Widget build(BuildContext context) {
     return new MaterialApp(
+      locale: locale,
       home: new Material(
         child: new Center(
           child: new Builder(
@@ -36,15 +41,18 @@ class _TimePickerLauncher extends StatelessWidget {
   }
 }
 
-Future<Offset> startPicker(WidgetTester tester, ValueChanged<TimeOfDay> onChanged) async {
-  await tester.pumpWidget(new _TimePickerLauncher(onChanged: onChanged));
+Future<Offset> startPicker(WidgetTester tester, ValueChanged<TimeOfDay> onChanged,
+    { Locale locale: const Locale('en', 'US') }) async {
+  await tester.pumpWidget(new _TimePickerLauncher(onChanged: onChanged, locale: locale,));
   await tester.tap(find.text('X'));
   await tester.pumpAndSettle(const Duration(seconds: 1));
   return tester.getCenter(find.byKey(const Key('time-picker-dial')));
 }
 
 Future<Null> finishPicker(WidgetTester tester) async {
-  await tester.tap(find.text('OK'));
+  final Element timePickerElement = tester.element(find.byElementPredicate((Element element) => element.widget.runtimeType.toString() == '_TimePickerDialog'));
+  final MaterialLocalizations materialLocalizations = MaterialLocalizations.of(timePickerElement);
+  await tester.tap(find.text(materialLocalizations.okButtonLabel));
   await tester.pumpAndSettle(const Duration(seconds: 1));
 }
 
@@ -197,4 +205,78 @@ void main() {
       expect(feedback.hapticCount, 3);
     });
   });
+
+  group('localization', () {
+    testWidgets('can localize the header in all known formats', (WidgetTester tester) async {
+      // TODO(yjbanov): also test `HH.mm` (in_ID), `a h:mm` (ko_KR) and `HH:mm น.` (th_TH) when we have .arb files for them
+      final Map<Locale, List<String>> locales = <Locale, List<String>>{
+        const Locale('en', 'US'): const <String>['hour h', 'string :', 'minute', 'period'], //'h:mm a'
+        const Locale('en', 'GB'): const <String>['hour HH', 'string :', 'minute'], //'HH:mm'
+        const Locale('es', 'ES'): const <String>['hour H', 'string :', 'minute'], //'H:mm'
+        const Locale('fr', 'CA'): const <String>['hour HH', 'string h', 'minute'], //'HH \'h\' mm'
+        const Locale('zh', 'ZH'): const <String>['period', 'hour h', 'string :', 'minute'], //'ah:mm'
+      };
+
+      for (Locale locale in locales.keys) {
+        final Offset center = await startPicker(tester, (TimeOfDay time) { }, locale: locale);
+        final List<String> actual = <String>[];
+        tester.element(find.byType(CustomMultiChildLayout)).visitChildren((Element child) {
+          final LayoutId layout = child.widget;
+          final String fragmentType = '${layout.child.runtimeType}';
+          final dynamic widget = layout.child;
+          if (fragmentType == '_MinuteControl') {
+            actual.add('minute');
+          } else if (fragmentType == '_DayPeriodControl') {
+            actual.add('period');
+          } else if (fragmentType == '_HourControl') {
+            actual.add('hour ${widget.hourFormat.toString().split('.').last}');
+          } else if (fragmentType == '_StringFragment') {
+            actual.add('string ${widget.value}');
+          } else {
+            fail('Unsupported fragment type: $fragmentType');
+          }
+        });
+        expect(actual, locales[locale]);
+        await tester.tapAt(new Offset(center.dx, center.dy - 50.0));
+        await finishPicker(tester);
+      }
+    });
+
+    testWidgets('uses single-ring 12-hour dial for h hour format', (WidgetTester tester) async {
+      // Tap along the segment stretching from the center to the edge at
+      // 12:00 AM position. Because there's only one ring, no matter where you
+      // tap the time will be the same. See the 24-hour dial test that behaves
+      // differently.
+      for (int i = 1; i < 10; i++) {
+        TimeOfDay result;
+        final Offset center = await startPicker(tester, (TimeOfDay time) { result = time; });
+        final Size size = tester.getSize(find.byKey(const Key('time-picker-dial')));
+        final double dy = (size.height / 2.0 / 10) * i;
+        await tester.tapAt(new Offset(center.dx, center.dy - dy));
+        await finishPicker(tester);
+        expect(result, equals(const TimeOfDay(hour: 0, minute: 0)));
+      }
+    });
+
+    testWidgets('uses two-ring 24-hour dial for H and HH hour formats', (WidgetTester tester) async {
+      const List<Locale> locales = const <Locale>[
+        const Locale('en', 'GB'), // HH
+        const Locale('es', 'ES'), // H
+      ];
+      for (Locale locale in locales) {
+        // Tap along the segment stretching from the center to the edge at
+        // 12:00 AM position. There are two rings. At ~70% mark, the ring
+        // switches between inner ring and outer ring.
+        for (int i = 1; i < 10; i++) {
+          TimeOfDay result;
+          final Offset center = await startPicker(tester, (TimeOfDay time) { result = time; }, locale: locale);
+          final Size size = tester.getSize(find.byKey(const Key('time-picker-dial')));
+          final double dy = (size.height / 2.0 / 10) * i;
+          await tester.tapAt(new Offset(center.dx, center.dy - dy));
+          await finishPicker(tester);
+          expect(result, equals(new TimeOfDay(hour: i < 7 ? 12 : 0, minute: 0)));
+        }
+      }
+    });
+  });
 }