How to I18n in Javafx and IntelliJ IDEA

Yesterday I noticed there is an important topic missing in my JavaFX workshop: Internationalization. So here is a SSCCE for that. It’s basically a copy of my recent commit to my JavaFX workshop.

This simple sample consists of two UI parts. In the north, there is a combo box with languages to choose from. In the center, there is a label that gets translated according to the selection in the combo box.

Internationalization

This is the main class that loads the simple UI and implements the language switch:

package de.stevenschwenke.java.javafx.workshop.chapter_3_advanced_basics;
 
import java.io.IOException;
import java.util.Locale;
import java.util.ResourceBundle;
 
import javafx.application.Application;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.fxml.FXMLLoader;
import javafx.scene.Scene;
import javafx.scene.control.ComboBox;
import javafx.scene.control.ListCell;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.Pane;
import javafx.stage.Stage;
import javafx.util.StringConverter;
 
/**
 * JavaFX offers a simple way to translate UI components. In this example, a simple gui implements
 * a language switch. The switch is basically a {@link ComboBox} with two languages to choose. The
 * content-part of the UI is loaded from an fxml file. In this file, the label's text is set to
 * "%label" which means that the text is going to be translated to whatever the set resource
 * bundle provides.
 */
public class E_13_Internationalization extends Application {
 
  BorderPane borderPane = new BorderPane();
 
  public static void main(String[] args) {
    launch(args);
  }
 
  @Override
  public void start(Stage stage) throws Exception {
    loadView(new Locale("en", "EN"));
    borderPane.setTop(createComboBox());
    stage.setScene(new Scene(borderPane));
    stage.setTitle("Internationalization");
    stage.show();
  }
 
  private ComboBox<Locale> createComboBox() {
    ComboBox<Locale> comboBox = new ComboBox<>();
    ObservableList<Locale> options = FXCollections.observableArrayList(Locale.ENGLISH, Locale.GERMAN);
    comboBox.setItems(options);
    comboBox.setConverter(new StringConverter<Locale>() {
      @Override
      public String toString(Locale object) {
        return object.getDisplayLanguage();
      }
 
      @Override
      public Locale fromString(String string) {
        return null;
      }
    });
    comboBox.setCellFactory(p -> new LanguageListCell());
    comboBox.getSelectionModel().selectFirst();
 
    comboBox.setOnAction(event -> loadView(comboBox.getSelectionModel().getSelectedItem()));
    return comboBox;
  }
 
  private void loadView(Locale locale) {
    try {
      FXMLLoader fxmlLoader = new FXMLLoader();
 
      // Here, just the resource bundles name is mentioned. You can add support for more languages
      // by adding more properties-files with language-specific endings like
      // "E_13_Internationalization_fr.properties".
      fxmlLoader.setResources(ResourceBundle.getBundle("E_13_Internationalization", locale));
 
      Pane pane = (BorderPane) fxmlLoader.load(this.getClass().getResource("/E_13_Internationalization.fxml").openStream());
      borderPane.setCenter(pane);
    } catch (IOException ex) {
      ex.printStackTrace();
    }
  }
 
  class LanguageListCell extends ListCell<Locale> {
    @Override protected void updateItem(Locale item, boolean empty) {
      super.updateItem(item, empty);
      if (item != null) {
        setText(item.getDisplayLanguage());
      }
    }
  }
}

This fxml-file is the center part of the UI. It just holds a label that gets translated:

<?xml version="1.0" encoding="UTF-8"?>
 
<?import javafx.scene.control.Label?>
<?import javafx.scene.layout.BorderPane?>
<BorderPane maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="400.0" prefWidth="600.0" xmlns="http://javafx.com/javafx/8.0.45" xmlns:fx="http://javafx.com/fxml/1" fx:controller="de.stevenschwenke.java.javafx.workshop.chapter_3_advanced_basics.E_13_Internationalization">
   <center>
 
      <!--  The "%" in the text-tag means that the text is going to be translated -->
      <Label text="%label" BorderPane.alignment="CENTER" />
   </center>
</BorderPane>

And finally the two properties-files for english and german language support:

label="Hier steht ein Text"
label="This is a text"

Intellij IDEA provides a really nice resource bundle editor for managing your translations. This thing allows you to manage the text of all your languages without having to crawl through your properties-files:

how to i18n in javafx and intellij idea

TL;DR

JavaFX provides an easy way to translate your UI texts in different languages. When using the resource bundle editor of IntelliJ IDEA, the management of UI texts is a piece of cake.