Pass full locale list with script and variant codes to framework

lib/ui/hooks.dart

@@ -42,14 +42,20 @@ void _updateWindowMetrics(double devicePixelRatio,
 
 typedef _LocaleClosure = String Function();
 
-String _localeClosure() => window._locale.toString();
+String _localeClosure() => window.locale.toString();
 
 @pragma('vm:entry-point')
 _LocaleClosure _getLocaleClosure() => _localeClosure;
 
 @pragma('vm:entry-point')
-void _updateLocale(String languageCode, String countryCode, String scriptCode, String variantCode) {
-  window._locale = new Locale(languageCode, countryCode);
+void _updateLocales(List<String> locales) {
+  const int stringsPerLocale = 4;
+  final int numLocales = locales.length ~/ stringsPerLocale;
+  window._locales = new List<Locale>(numLocales);
+  for (int localeIndex = 0; localeIndex < numLocales; localeIndex++) {
+    window._locales[localeIndex] = new Locale(locales[localeIndex * stringsPerLocale],
+                                   locales[localeIndex * stringsPerLocale + 1]);
+  }
   _invoke(window.onLocaleChanged, window._onLocaleChangedZone);
 }
 

lib/ui/window.dart

@@ -152,6 +152,9 @@ class Locale {
   /// the region subtag should be uppercase.
   const Locale(this._languageCode, [ this._countryCode ]) : assert(_languageCode != null);
 
+  /// Empty locale constant. This is an invalid locale.
+  static const Locale none = const Locale('', '');
+
   /// The primary language subtag for the locale.
   ///
   /// This must not be null.
@@ -426,19 +429,39 @@ class Window {
     _onMetricsChangedZone = Zone.current;
   }
 
-  /// The system-reported locale.
+  /// The system-reported default locale of the device.
+  ///
+  /// This establishes the language and formatting conventions that application
+  /// should, if possible, use to render their user interface.
+  ///
+  /// This is the first locale selected by the user and is the user's
+  /// primary locale (the locale the device UI is displayed in)
+  ///
+  /// This is equivalent to `locales.first` and will provide an empty non-null locale
+  /// if the [locales] list has not been set or is empty.
+  Locale get locale {
+    if (_locales != null && _locales.isNotEmpty) {
+      return _locales.first;
+    }
+    return Locale.none;
+  }
+
+  /// The full system-reported supported locales of the device.
   ///
   /// This establishes the language and formatting conventions that application
   /// should, if possible, use to render their user interface.
   ///
+  /// The list is ordered in order of priority, with lower-indexed locales being
+  /// preferred over higher-indexed ones. The first element is the primary [locale].
+  ///
   /// The [onLocaleChanged] callback is called whenever this value changes.
   ///
   /// See also:
   ///
   ///  * [WidgetsBindingObserver], for a mechanism at the widgets layer to
   ///    observe when this value changes.
-  Locale get locale => _locale;
-  Locale _locale;
+  List<Locale> get locales => _locales;
+  List<Locale> _locales;
 
   /// A callback that is invoked whenever [locale] changes value.
   ///

lib/ui/window/window.cc

@@ -162,21 +162,14 @@ void Window::UpdateWindowMetrics(const ViewportMetrics& metrics) {
                   });
 }
 
-void Window::UpdateLocale(const std::string& language_code,
-                          const std::string& country_code,
-                          const std::string& script_code,
-                          const std::string& variant_code) {
+void Window::UpdateLocales(const std::vector<std::string>& locales) {
   std::shared_ptr<tonic::DartState> dart_state = library_.dart_state().lock();
   if (!dart_state)
     return;
   tonic::DartState::Scope scope(dart_state);
-
-  DartInvokeField(library_.value(), "_updateLocale",
+  DartInvokeField(library_.value(), "_updateLocales",
                   {
-                      StdStringToDart(language_code),
-                      StdStringToDart(country_code),
-                      StdStringToDart(script_code),
-                      StdStringToDart(variant_code),
+                      tonic::ToDart<std::vector<std::string>>(locales),
                   });
 }
 

lib/ui/window/window.h

@@ -5,7 +5,9 @@
 #ifndef FLUTTER_LIB_UI_WINDOW_WINDOW_H_
 #define FLUTTER_LIB_UI_WINDOW_WINDOW_H_
 
+#include <string>
 #include <unordered_map>
+#include <vector>
 
 #include "flutter/fml/time/time_point.h"
 #include "flutter/lib/ui/semantics/semantics_update.h"
@@ -59,10 +61,7 @@ class Window final {
 
   void DidCreateIsolate();
   void UpdateWindowMetrics(const ViewportMetrics& metrics);
-  void UpdateLocale(const std::string& language_code,
-                    const std::string& country_code,
-                    const std::string& script_code,
-                    const std::string& variant_code);
+  void UpdateLocales(const std::vector<std::string>& locales);
   void UpdateUserSettingsData(const std::string& data);
   void UpdateSemanticsEnabled(bool enabled);
   void UpdateAccessibilityFeatures(int32_t flags);

runtime/runtime_controller.cc

@@ -124,8 +124,7 @@ std::unique_ptr<RuntimeController> RuntimeController::Clone() const {
 
 bool RuntimeController::FlushRuntimeStateToIsolate() {
   return SetViewportMetrics(window_data_.viewport_metrics) &&
-         SetLocale(window_data_.language_code, window_data_.country_code,
-                   window_data_.script_code, window_data_.variant_code) &&
+         SetLocales(window_data_.locale_data) &&
          SetSemanticsEnabled(window_data_.semantics_enabled) &&
          SetAccessibilityFeatures(window_data_.accessibility_feature_flags_);
 }
@@ -140,22 +139,15 @@ bool RuntimeController::SetViewportMetrics(const ViewportMetrics& metrics) {
   return false;
 }
 
-bool RuntimeController::SetLocale(const std::string& language_code,
-                                  const std::string& country_code,
-                                  const std::string& script_code,
-                                  const std::string& variant_code) {
-  window_data_.language_code = language_code;
-  window_data_.country_code = country_code;
-  window_data_.script_code = script_code;
-  window_data_.variant_code = variant_code;
+bool RuntimeController::SetLocales(
+    const std::vector<std::string>& locale_data) {
+  window_data_.locale_data = locale_data;
 
   if (auto window = GetWindowIfAvailable()) {
-    window->UpdateLocale(window_data_.language_code, window_data_.country_code,
-                         window_data_.script_code, window_data_.variant_code);
+    window->UpdateLocales(locale_data);
     return true;
   }
-
-  return false;
+  return true;
 }
 
 bool RuntimeController::SetUserSettingsData(const std::string& data) {

runtime/runtime_controller.h

@@ -6,6 +6,7 @@
 #define FLUTTER_RUNTIME_RUNTIME_CONTROLLER_H_
 
 #include <memory>
+#include <vector>
 
 #include "flutter/common/task_runners.h"
 #include "flutter/flow/layers/layer_tree.h"
@@ -15,6 +16,8 @@
 #include "flutter/lib/ui/window/pointer_data_packet.h"
 #include "flutter/lib/ui/window/window.h"
 #include "flutter/runtime/dart_vm.h"
+#include "rapidjson/document.h"
+#include "rapidjson/stringbuffer.h"
 
 namespace blink {
 class Scene;
@@ -40,10 +43,7 @@ class RuntimeController final : public WindowClient {
 
   bool SetViewportMetrics(const ViewportMetrics& metrics);
 
-  bool SetLocale(const std::string& language_code,
-                 const std::string& country_code,
-                 const std::string& script_code,
-                 const std::string& variant_code);
+  bool SetLocales(const std::vector<std::string>& locale_data);
 
   bool SetUserSettingsData(const std::string& data);
 
@@ -78,12 +78,29 @@ class RuntimeController final : public WindowClient {
   std::pair<bool, uint32_t> GetRootIsolateReturnCode();
 
  private:
+  struct Locale {
+    Locale(std::string language_code_,
+           std::string country_code_,
+           std::string script_code_,
+           std::string variant_code_)
+        : language_code(language_code_),
+          country_code(country_code_),
+          script_code(script_code_),
+          variant_code(variant_code_) {}
+
+    std::string language_code;
+    std::string country_code;
+    std::string script_code;
+    std::string variant_code;
+  };
+
   struct WindowData {
     ViewportMetrics viewport_metrics;
     std::string language_code;
     std::string country_code;
     std::string script_code;
     std::string variant_code;
+    std::vector<std::string> locale_data;
     std::string user_settings_data = "{}";
     bool semantics_enabled = false;
     bool assistive_technology_enabled = false;

shell/common/engine.cc

@@ -7,6 +7,7 @@
 #include <memory>
 #include <string>
 #include <utility>
+#include <vector>
 
 #include "flutter/common/settings.h"
 #include "flutter/fml/eintr_wrapper.h"
@@ -325,17 +326,22 @@ bool Engine::HandleLocalizationPlatformMessage(
   if (args == root.MemberEnd() || !args->value.IsArray())
     return false;
 
-  const auto& language = args->value[0];
-  const auto& country = args->value[1];
-  const auto& script = args->value[2];
-  const auto& variant = args->value[3];
-
-  if (!language.IsString() || !country.IsString())
+  const size_t strings_per_locale = 4;
+  if (args->value.Size() % strings_per_locale != 0)
     return false;
+  std::vector<std::string> locale_data;
+  for (size_t locale_index = 0; locale_index < args->value.Size();
+       locale_index += strings_per_locale) {
+    if (!args->value[locale_index].IsString() ||
+        !args->value[locale_index + 1].IsString())
+      return false;
+    locale_data.push_back(args->value[locale_index].GetString());
+    locale_data.push_back(args->value[locale_index + 1].GetString());
+    locale_data.push_back(args->value[locale_index + 2].GetString());
+    locale_data.push_back(args->value[locale_index + 3].GetString());
+  }
 
-  return runtime_controller_->SetLocale(language.GetString(),
-                                        country.GetString(), script.GetString(),
-                                        variant.GetString());
+  return runtime_controller_->SetLocales(locale_data);
 }
 
 void Engine::HandleSettingsPlatformMessage(blink::PlatformMessage* message) {

shell/platform/android/io/flutter/view/FlutterView.java

@@ -37,6 +37,7 @@
 import org.json.JSONException;
 import org.json.JSONObject;
 
+import java.lang.reflect.Method;
 import java.net.URI;
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
@@ -170,7 +171,8 @@ public void surfaceDestroyed(SurfaceHolder holder) {
         mImm = (InputMethodManager) getContext().getSystemService(Context.INPUT_METHOD_SERVICE);
         mTextInputPlugin = new TextInputPlugin(this);
 
-        setLocale(getResources().getConfiguration().locale);
+
+        setLocales(getResources().getConfiguration());
         setUserSettings();
     }
 
@@ -316,14 +318,43 @@ private void setUserSettings() {
         mFlutterSettingsChannel.send(message);
     }
 
-    private void setLocale(Locale locale) {
+    private void setLocales(Configuration config) {
+        if (Build.VERSION.SDK_INT >= 24) {
+            try {
+                // Passes the full list of locales for android API >= 24 with reflection.
+                Object localeList = config.getClass().getDeclaredMethod("getLocales").invoke(config);
+                Method localeListGet = localeList.getClass().getDeclaredMethod("get", int.class);
+                Method localeListSize = localeList.getClass().getDeclaredMethod("size");
+                int localeCount = (int)localeListSize.invoke(localeList);
+                List<String> data = new ArrayList<String>();
+                for (int index = 0; index < localeCount; ++index) {
+                    Locale locale = (Locale)localeListGet.invoke(localeList, index);
+                    data.add(locale.getLanguage());
+                    data.add(locale.getCountry());
+                    data.add(locale.getScript());
+                    data.add(locale.getVariant());
+                }
+                mFlutterLocalizationChannel.invokeMethod("setLocale", data);
+                return;
+            } catch (Exception exception) {
+                // Any exception is a failure. Resort to fallback of sending only one locale.
+            }
+        }
+        // Fallback single locale passing for android API < 24. Should work always.
+        Locale locale = config.locale;
+        List<String> data = new ArrayList<String>();
+        data.add(locale.getLanguage());
+        data.add(locale.getCountry());
+        data.add(locale.getScript());
+        data.add(locale.getVariant());
         mFlutterLocalizationChannel.invokeMethod("setLocale", Arrays.asList(locale.getLanguage(), locale.getCountry(), locale.getScript(), locale.getVariant()));
+
     }
 
     @Override
     protected void onConfigurationChanged(Configuration newConfig) {
         super.onConfigurationChanged(newConfig);
-        setLocale(newConfig.locale);
+        setLocales(newConfig);
         setUserSettings();
     }
 

shell/platform/darwin/ios/framework/Source/FlutterViewController.mm

@@ -905,19 +905,26 @@ - (void)onMemoryWarning:(NSNotification*)notification {
 #pragma mark - Locale updates
 
 - (void)onLocaleUpdated:(NSNotification*)notification {
-  NSLocale* currentLocale = [NSLocale currentLocale];
-  NSString* languageCode = [currentLocale objectForKey:NSLocaleLanguageCode];
-  NSString* countryCode = [currentLocale objectForKey:NSLocaleCountryCode];
-  NSString* scriptCode = [currentLocale objectForKey:NSLocaleScriptCode];
-  NSString* variantCode = [currentLocale objectForKey:NSLocaleVariantCode];
-  if (languageCode && countryCode)
-    // We pass empty strings for undefined scripts and variants to ensure the JSON encoder/decoder
-    // functions properly.
-    [_localizationChannel.get() invokeMethod:@"setLocale"
-                                   arguments:@[
-                                     languageCode, countryCode, scriptCode ? scriptCode : @"",
-                                     variantCode ? variantCode : @""
-                                   ]];
+  NSArray<NSString*>* preferredLocales = [NSLocale preferredLanguages];
+  NSMutableArray<NSString*>* data = [NSMutableArray new];
+  for (NSString* localeID in preferredLocales) {
+    NSLocale* currentLocale = [[NSLocale alloc] initWithLocaleIdentifier:localeID];
+    NSString* languageCode = [currentLocale objectForKey:NSLocaleLanguageCode];
+    NSString* countryCode = [currentLocale objectForKey:NSLocaleCountryCode];
+    NSString* scriptCode = [currentLocale objectForKey:NSLocaleScriptCode];
+    NSString* variantCode = [currentLocale objectForKey:NSLocaleVariantCode];
+    if (!languageCode || !countryCode) {
+      continue;
+    }
+    [data addObject:languageCode];
+    [data addObject:countryCode];
+    [data addObject:(scriptCode ? scriptCode : @"")];
+    [data addObject:(variantCode ? variantCode : @"")];
+  }
+  if (data.count == 0) {
+    return;
+  }
+  [_localizationChannel.get() invokeMethod:@"setLocale" arguments:data];
 }
 
 #pragma mark - Set user settings

testing/dart/window_hooks_integration_test.dart

@@ -100,7 +100,7 @@ void main() {
         };
       });
 
-      _updateLocale('en', 'US', '', '');
+      _updateLocales(<String>['en', 'US', '', '']);
       expect(runZone, isNotNull);
       expect(runZone, same(innerZone));
       expect(locale, equals(const Locale('en', 'US')));