JavaFX WebView grow to fill entire area

One approach is to add the WebView to a StackPane, which "will attempt to resize each child to fill its content area." I've given the enclosing JFXPanel to an arbitrary preferred size of 640 x 480; resize the frame to see how the StackPane reflows the WebView content based on the default Pos.CENTER.

import java.awt.BorderLayout;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;
import javafx.application.Platform;
import javafx.embed.swing.JFXPanel;
import javafx.scene.Scene;
import javafx.scene.layout.StackPane;
import javafx.scene.web.WebEngine;
import javafx.scene.web.WebView;

/** @see https://stackoverflow.com/a/31576647/230513 */
public class WebViewTest {

    private void initAndShowGUI() {
        // This method is invoked on the EDT thread
        JFrame frame = new JFrame("Swing and JavaFX");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        final JFXPanel fxPanel = new JFXPanel(){

            @Override
            public Dimension getPreferredSize() {
                return new Dimension(640, 480);
            }
        };
        frame.add(fxPanel, BorderLayout.CENTER);
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);

        Platform.runLater(() -> {
            initFX(fxPanel);
        });
    }

    private void initFX(JFXPanel fxPanel) {
        // This method is invoked on the JavaFX thread
        Scene scene = createScene();
        fxPanel.setScene(scene);
    }

    private Scene createScene() {
        StackPane root = new StackPane();
        Scene scene = new Scene(root);
        WebView  webView = new WebView();
        WebEngine webEngine = webView.getEngine();
        webEngine.load("http://www.example.com");
        root.getChildren().add(webView);
        return scene;
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new WebViewTest()::initAndShowGUI);
    }
}

Actually, I think I got a solution based off http://docs.oracle.com/javafx/2/webview/WebViewSample.java.htm:

import java.awt.BorderLayout;

import javax.swing.JFrame;
import javax.swing.JPanel;

import javafx.application.Platform;
import javafx.embed.swing.JFXPanel;
import javafx.geometry.HPos;
import javafx.geometry.VPos;
import javafx.scene.Scene;
import javafx.scene.layout.Region;
import javafx.scene.paint.Color;
import javafx.scene.web.WebEngine;
import javafx.scene.web.WebView;
import javafx.stage.Stage;


public class WebViewSample {

    public static void main(String[] args) {

        JFrame frame = new JFrame("Swing and JavaFX");
        frame.setSize(1000, 1000);
        frame.setVisible(true);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JPanel panel = new JPanel(new BorderLayout(0, 0));
        frame.getContentPane().add(panel, BorderLayout.CENTER);

        final JFXPanel jfxPanel = new JFXPanel();
        panel.add(jfxPanel);

        Platform.runLater(new Runnable() {
            @Override
            public void run() {
                initFx(jfxPanel);
            }
       });
    }

    private static void initFx(JFXPanel fxPanel) {
        Stage stage = new Stage();
        stage.setTitle("Web View");
        Scene scene = new Scene(new Browser(), 1000, 1000, Color.web("#666970"));
        stage.setScene(scene);
        fxPanel.setScene(scene);
    }

}

class Browser extends Region {

    final WebView browser = new WebView();
    final WebEngine webEngine = browser.getEngine();

    public Browser() {
        // load the home page
        webEngine.load("http://www.google.com");

        //add components
        getChildren().add(browser);
    }

    @Override
    protected void layoutChildren() {
        double w = getWidth();
        double h = getHeight();
        layoutInArea(browser,0,0,w,h,0,HPos.CENTER,VPos.CENTER);
    }

}

I think the trick is to subclass Region, so that you can layout the WebView where you want it manually.