How to listen to WindowEvent.WINDOW_SHOWN in scene graph nodes?

Question

It seems that WindowEvent.WINDOW_SHOWN never goes to any of the nodes in the scene graph and does not exist (what I can find) to know when the node is displayed / displayed / displayed. For example:

TestLauncher.java

package com.example.javafx.event; import javafx.application.Application; import javafx.fxml.FXMLLoader; import javafx.scene.Parent; import javafx.scene.Scene; import javafx.stage.Stage; public class TestLauncher extends Application { public static void main(String[] args) { Application.launch(TestLauncher.class, args); } @Override public void start(Stage stage) throws Exception { Parent root = FXMLLoader.load(TestController.class.getResource("TestView.fxml")); Scene scene = new Scene(root); stage.setScene(scene); stage.show(); } } 

TestController.java

 package com.example.javafx.event; import java.net.URL; import java.util.ResourceBundle; import javafx.event.EventHandler; import javafx.fxml.FXML; import javafx.fxml.Initializable; import javafx.scene.Parent; import javafx.scene.control.TextField; import javafx.stage.WindowEvent; public class TestController implements Initializable { @FXML private Parent root; @FXML private TextField serverAddressInput; @FXML private TextField usernameInput; @Override public void initialize(URL url, ResourceBundle rb) { serverAddressInput.setText("127.0.0.1"); //won't work because stage isn't visible yet trySetFocusOnUsernameInput1(); //apparently Stage never passes on any WindowEvents to the children... trySetFocusOnUsernameInput2(); } private void trySetFocusOnUsernameInput1() { usernameInput.requestFocus(); } private void trySetFocusOnUsernameInput2() { root.addEventFilter(WindowEvent.WINDOW_SHOWN, new EventHandler<WindowEvent>() { @Override public void handle(WindowEvent window) { usernameInput.requestFocus(); } }); root.addEventHandler(WindowEvent.WINDOW_SHOWN, new EventHandler<WindowEvent>() { @Override public void handle(WindowEvent window) { usernameInput.requestFocus(); } }); } public void handleWindowShownEvent() { usernameInput.requestFocus(); } } 

TestView.fxml

 <?xml version="1.0" encoding="UTF-8"?> <?import java.lang.*?> <?import javafx.scene.*?> <?import javafx.scene.control.*?> <?import javafx.scene.layout.*?> <VBox xmlns:fx="http://javafx.com/fxml" fx:id="root" fx:controller="com.example.javafx.event.TestController" prefHeight="150" prefWidth="200" > <children> <TextField fx:id="serverAddressInput" /> <TextField fx:id="usernameInput" /> </children> </VBox> 

So actually, how else can a node know that it is being displayed / displayed / displayed?

Answer 1

I think one possible solution is to add the following method to TestController.java

  public void handleWindowShownEvent() { usernameInput.requestFocus(); } 

and then change the start method in TestLauncher to the following:

  @Override public void start(Stage stage) throws Exception { FXMLLoader loader = new FXMLLoader(); Parent root = (Parent)loader.load(TestController.class.getResourceAsStream("TestView.fxml")); final TestController controller = (TestController)loader.getController(); stage.addEventHandler(WindowEvent.WINDOW_SHOWN, new EventHandler<WindowEvent>() { @Override public void handle(WindowEvent window) { controller.handleWindowShownEvent(); } }); Scene scene = new Scene(root); stage.setScene(scene); stage.show(); } 

I would really welcome other solutions as this one seems too awkward ...

Answer 2

Another solution that is admittedly not very sexy, but separates node from application:

 root.sceneProperty().addListener(new ChangeListener<Scene>() { @Override public void changed(ObservableValue<? extends Scene> observable, Scene oldValue, Scene newValue) { newValue.windowProperty().addListener(new ChangeListener<Window>() { @Override public void changed(ObservableValue<? extends Window> observable, Window oldValue, Window newValue) { newValue.addEventHandler(WindowEvent.WINDOW_SHOWN, new EventHandler<WindowEvent>() { @Override public void handle(WindowEvent event) { usernameInput.requestFocus(); } }); } }); } }); 

In my case, it made more sense.