Support for Thai language

lib/src/date_picker_theme.dart

@@ -20,7 +20,7 @@ const double DATETIME_PICKER_ITEM_HEIGHT = 36.0;
 const TextStyle DATETIME_PICKER_ITEM_TEXT_STYLE =
     const TextStyle(color: Color(0xFF000046), fontSize: 16.0);
 
-class DateTimePickerTheme with DiagnosticableMixin {
+class DateTimePickerTheme with Diagnosticable {
   final cancelDefault = const Text('OK');
 
   /// DateTimePicker theme.

lib/src/i18n/date_picker_i18n.dart

@@ -24,6 +24,7 @@ part 'strings_fr.dart';
 part 'strings_sr_cyr.dart';
 part 'strings_sr_lat.dart';
 part 'strings_nl.dart';
+part 'strings_th.dart';
 
 abstract class _StringsI18n {
   const _StringsI18n();
@@ -119,6 +120,9 @@ enum DateTimePickerLocale {
 
   /// Dutch (NL)
   nl,
+
+  /// Thai (TH)
+  th_th,
 }
 
 /// Default value of date locale
@@ -150,6 +154,7 @@ const Map<DateTimePickerLocale, _StringsI18n> datePickerI18n = {
   DateTimePickerLocale.sr_cyrl: const _StringsSrCyrillic(),
   DateTimePickerLocale.sr_latn: const _StringsSrLatin(),
   DateTimePickerLocale.nl: const _StringsNl(),
+  DateTimePickerLocale.th_th: const _StringsTh(),
 };
 
 class DatePickerI18n {

lib/src/i18n/strings_th.dart

@@ -0,0 +1,78 @@
+part of 'date_picker_i18n.dart';
+
+/// Thai (TH)
+class _StringsTh extends _StringsI18n {
+  const _StringsTh();
+
+  @override
+  String getCancelText() {
+    return "ยกเลิก";
+  }
+
+  @override
+  String getDoneText() {
+    return "เรียบร้อย";
+  }
+
+  @override
+  List<String> getMonths() {
+    return [
+      "มกราคม",
+      "กุมภาพันธ์",
+      "มีนาคม",
+      "เมษายน",
+      "พฤษภาคม",
+      "มิถุนายน",
+      "กรกฎาคม",
+      "สิงหาคม",
+      "กันยายน",
+      "ตุลาคม",
+      "พฤศจิกายน",
+      "ธันวาคม",
+    ];
+  }
+
+  @override
+  List<String> getMonthsShort() {
+    return [
+      "ม.ค.",
+      "ก.พ.",
+      "มี.ค.",
+      "เม.ย.",
+      "พ.ค.",
+      "มิ.ย.",
+      "ก.ค.",
+      "ส.ค.",
+      "ก.ย.",
+      "ต.ค.",
+      "พ.ย.",
+      "ธ.ค.",
+    ];
+  }
+
+  @override
+  List<String> getWeeksFull() {
+    return [
+      "จันทร์",
+      "อังคาร",
+      "พุธ",
+      "พฤหัสบดี",
+      "ศุกร์",
+      "เสาร์",
+      "อาทิตย์",
+    ];
+  }
+
+  @override
+  List<String> getWeeksShort() {
+    return [
+      "จ",
+      "อ",
+      "พ",
+      "พฤ",
+      "ศ",
+      "ส",
+      "อา",
+    ];
+  }
+}