Added a menu option for selecting the application language

es-app/src/guis/GuiMenu.cpp

@@ -473,6 +473,31 @@ void GuiMenu::openUIOptions()
     themeTransitionsFunc(Settings::getInstance()->getString("Theme"),
                          Settings::getInstance()->getString("ThemeTransitions"));
 
+    // Application language.
+    auto applicationLanguage = std::make_shared<OptionListComponent<std::string>>(
+        getHelpStyle(), "APPLICATION LANGUAGE", false);
+    std::string selectedApplicationLanguage {
+        Settings::getInstance()->getString("ApplicationLanguage")};
+    applicationLanguage->add("AUTOMATIC", "automatic", selectedApplicationLanguage == "automatic");
+    applicationLanguage->add("ENGLISH (AMERICAN)", "en_US", selectedApplicationLanguage == "en_US");
+    applicationLanguage->add("SWEDISH", "sv_SE", selectedApplicationLanguage == "sv_SE");
+    // If there are no objects returned, then there must be a manually modified entry in the
+    // configuration file. Simply set the application langauge to "automatic" in this case.
+    if (applicationLanguage->getSelectedObjects().size() == 0)
+        applicationLanguage->selectEntry(0);
+    s->addWithLabel("APPLICATION LANGUAGE", applicationLanguage);
+    s->addSaveFunc([this, applicationLanguage, s] {
+        if (applicationLanguage->getSelected() !=
+            Settings::getInstance()->getString("ApplicationLanguage")) {
+            Settings::getInstance()->setString("ApplicationLanguage",
+                                               applicationLanguage->getSelected());
+            Utils::Localization::setLocale();
+            s->setNeedsSaving();
+            s->setNeedsCloseMenu([this] { delete this; });
+            s->setNeedsRescanROMDirectory();
+        }
+    });
+
     // Quick system select (navigate between systems in the gamelist view).
     auto quickSystemSelect = std::make_shared<OptionListComponent<std::string>>(
         getHelpStyle(), "QUICK SYSTEM SELECT", false);

es-app/src/main.cpp

@@ -733,7 +733,7 @@ int main(int argc, char* argv[])
         return 0;
     }
 
-    Utils::Localization::setLocale(Utils::Localization::getLocale());
+    Utils::Localization::setLocale();
     Scripting::fireEvent("startup");
 
 #if defined(__EMSCRIPTEN__)

es-core/src/Settings.cpp

@@ -43,6 +43,7 @@ namespace
 
         // These options are only used internally during the application session:
         "PortableMode",
+        "DetectedLocale",
         "DebugGrid",
         "DebugText",
         "DebugImage",
@@ -168,6 +169,7 @@ void Settings::setDefaults()
     mStringMap["ThemeFontSize"] = {"", ""};
     mStringMap["ThemeAspectRatio"] = {"", ""};
     mStringMap["ThemeTransitions"] = {"automatic", "automatic"};
+    mStringMap["ApplicationLanguage"] = {"automatic", "automatic"};
     mStringMap["QuickSystemSelect"] = {"leftrightshoulders", "leftrightshoulders"};
     mStringMap["StartupSystem"] = {"", ""};
     mStringMap["SystemsSorting"] = {"default", "default"};
@@ -363,6 +365,7 @@ void Settings::setDefaults()
 
     mIntMap["ApplicationRelease"] = {0, 0};
     mStringMap["ApplicationUpdaterLastCheck"] = {"", ""};
+    mStringMap["DetectedLocale"] = {"", ""};
     mBoolMap["PortableMode"] = {false, false};
     mBoolMap["DebugFlag"] = {false, false};
     mBoolMap["DebugGrid"] = {false, false};

es-core/src/utils/LocalizationUtil.cpp

@@ -10,6 +10,7 @@
 #include "utils/LocalizationUtil.h"
 
 #include "Log.h"
+#include "Settings.h"
 #include "resources/ResourceManager.h"
 #include "utils/StringUtil.h"
 
@@ -72,8 +73,35 @@ namespace Utils
 #endif
         }
 
-        void setLocale(const std::pair<std::string, std::string>& localePair)
+        void setLocale()
         {
+            // Only detect locale once (on application startup).
+            if (Settings::getInstance()->getString("DetectedLocale") == "") {
+                const std::pair<std::string, std::string> detectedLocale {getLocale()};
+                if (detectedLocale.second == "")
+                    Settings::getInstance()->setString("DetectedLocale", detectedLocale.first);
+                else {
+                    Settings::getInstance()->setString(
+                        "DetectedLocale", detectedLocale.first + "_" + detectedLocale.second);
+                }
+            }
+
+            std::string languageSetting {Settings::getInstance()->getString("ApplicationLanguage")};
+            std::vector<std::string> localeVector;
+            std::pair<std::string, std::string> localePair;
+
+            if (languageSetting == "automatic") {
+                localeVector = Utils::String::delimitedStringToVector(
+                    Settings::getInstance()->getString("DetectedLocale"), "_");
+            }
+            else {
+                localeVector = Utils::String::delimitedStringToVector(languageSetting, "_");
+            }
+            if (localeVector.size() == 1)
+                localePair = std::make_pair(localeVector[0], "");
+            else
+                localePair = std::make_pair(localeVector[0], localeVector[1]);
+
             std::string locale;
             std::string localePairCombined;
 

es-core/src/utils/LocalizationUtil.h

@@ -24,7 +24,7 @@ namespace Utils
             {{"en"}, {"US"}}, {{"sv"}, {"SE"}}};
 
         std::pair<std::string, std::string> getLocale();
-        void setLocale(const std::pair<std::string, std::string>& localePair);
+        void setLocale();
 
     } // namespace Localization