display "language" chooser in general preferences

src/main/java/org/cryptomator/launcher/SupportedLanguages.java

@@ -0,0 +1,12 @@
+package org.cryptomator.launcher;
+
+import java.util.List;
+
+public class SupportedLanguages {
+
+	// these are BCP 47 language codes, not ISO. Note the "-" instead of the "_":
+	public static List<String> LANGUAGAE_TAGS = List.of("ar", "bn", "bs", "ca", "cs", "de", "el", "es", "fil", "fr", "gl", "he", //
+			"hi", "hr", "hu", "id", "it", "ja", "ko", "lv", "mk", "nb", "nl", "nn", "no", "pa", "pl", "pt", "pt-BR", "ro", "ru", //
+			"sk", "sr", "sr-Latn", "sv", "ta", "te", "th", "tr", "uk", "zh", "zh-HK", "zh-TW");
+
+}

src/main/java/org/cryptomator/ui/preferences/GeneralPreferencesController.java

@@ -1,5 +1,6 @@
 package org.cryptomator.ui.preferences;
 
+import com.google.common.base.Strings;
 import org.cryptomator.common.Environment;
 import org.cryptomator.common.LicenseHolder;
 import org.cryptomator.common.settings.Settings;
@@ -7,6 +8,7 @@ import org.cryptomator.common.settings.UiTheme;
 import org.cryptomator.integrations.autostart.AutoStartProvider;
 import org.cryptomator.integrations.autostart.ToggleAutoStartFailedException;
 import org.cryptomator.integrations.keychain.KeychainAccessProvider;
+import org.cryptomator.launcher.SupportedLanguages;
 import org.cryptomator.ui.common.FxController;
 import org.cryptomator.ui.fxapp.FxApplicationWindows;
 import org.cryptomator.ui.traymenu.TrayMenuComponent;
@@ -27,6 +29,7 @@ import javafx.scene.control.Toggle;
 import javafx.scene.control.ToggleGroup;
 import javafx.stage.Stage;
 import javafx.util.StringConverter;
+import java.util.Locale;
 import java.util.Optional;
 import java.util.ResourceBundle;
 import java.util.Set;
@@ -53,6 +56,7 @@ public class GeneralPreferencesController implements FxController {
 	public CheckBox showMinimizeButtonCheckbox;
 	public CheckBox showTrayIconCheckbox;
 	public CheckBox startHiddenCheckbox;
+	public ChoiceBox<String> preferredLanguageChoiceBox;
 	public CheckBox debugModeCheckbox;
 	public CheckBox autoStartCheckbox;
 	public ToggleGroup nodeOrientation;
@@ -90,6 +94,11 @@ public class GeneralPreferencesController implements FxController {
 
 		startHiddenCheckbox.selectedProperty().bindBidirectional(settings.startHidden());
 
+		preferredLanguageChoiceBox.getItems().add(null);
+		preferredLanguageChoiceBox.getItems().addAll(SupportedLanguages.LANGUAGAE_TAGS);
+		preferredLanguageChoiceBox.valueProperty().bindBidirectional(settings.languageProperty());
+		preferredLanguageChoiceBox.setConverter(new LanguageTagConverter(resourceBundle));
+
 		debugModeCheckbox.selectedProperty().bindBidirectional(settings.debugMode());
 
 		autoStartProvider.ifPresent(autoStart -> autoStartCheckbox.setSelected(autoStart.isEnabled()));
@@ -183,6 +192,32 @@ public class GeneralPreferencesController implements FxController {
 
 	}
 
+	private static class LanguageTagConverter extends StringConverter<String> {
+
+		private final ResourceBundle resourceBundle;
+
+		LanguageTagConverter(ResourceBundle resourceBundle) {
+			this.resourceBundle = resourceBundle;
+		}
+
+		@Override
+		public String toString(String tag) {
+			if (tag == null) {
+				return resourceBundle.getString("preferences.general.language.auto");
+			} else {
+				var locale = Locale.forLanguageTag(tag);
+				var lang = locale.getDisplayLanguage(locale);
+				var region = locale.getDisplayCountry(locale);
+				return lang + (Strings.isNullOrEmpty(region) ? "" : " (" + region + ")");
+			}
+		}
+
+		@Override
+		public String fromString(String displayLanguage) {
+			throw new UnsupportedOperationException();
+		}
+	}
+
 	private class KeychainProviderDisplayNameConverter extends StringConverter<KeychainAccessProvider> {
 
 		@Override

src/main/resources/fxml/preferences_general.fxml

@@ -38,6 +38,11 @@
 
 		<CheckBox fx:id="startHiddenCheckbox" text="%preferences.general.startHidden" />
 
+		<HBox spacing="6" alignment="CENTER_LEFT">
+			<Label text="%preferences.general.language"/>
+			<ChoiceBox fx:id="preferredLanguageChoiceBox"/>
+		</HBox>
+
 		<HBox spacing="6" alignment="CENTER_LEFT">
 			<CheckBox fx:id="debugModeCheckbox" text="%preferences.general.debugLogging"/>
 			<Hyperlink styleClass="hyperlink-underline" text="%preferences.general.debugDirectory" onAction="#showLogfileDirectory"/>

src/main/resources/i18n/strings.properties

@@ -199,6 +199,8 @@ preferences.general.unlockThemes=Unlock dark mode
 preferences.general.showMinimizeButton=Show minimize button
 preferences.general.showTrayIcon=Show tray icon (requires restart)
 preferences.general.startHidden=Hide window when starting Cryptomator
+preferences.general.language=Language (requires restart)
+preferences.general.language.auto=System Default
 preferences.general.debugLogging=Enable debug logging
 preferences.general.debugDirectory=Reveal log files
 preferences.general.autoStart=Launch Cryptomator on system start