JavaFX stop opening URL in WebView - open in browser instead

Question

The embedded WebView browser I am using needs special handling for particular URLs, to open them in the native default browser instead of WebView. The actual browsing part w

Answer 1

There is another method for handling this.

You can add an event listener to the DOM elements and intercept it that way.

Example:

NodeList nodeList = document.getElementsByTagName("a");
            for (int i = 0; i < nodeList.getLength(); i++)
            {
                Node node= nodeList.item(i);
                EventTarget eventTarget = (EventTarget) node;
                eventTarget.addEventListener("click", new EventListener()
                {
                    @Override
                    public void handleEvent(Event evt)
                    {
                        EventTarget target = evt.getCurrentTarget();
                        HTMLAnchorElement anchorElement = (HTMLAnchorElement) target;
                        String href = anchorElement.getHref();
                        //handle opening URL outside JavaFX WebView
                        System.out.println(href);
                        evt.preventDefault();
                    }
                }, false);
            }

Where document is the DOM document object. Make sure this is done after the document has finished loading.

Answer 2

I found another solution:

1. Register a CreatePopupHandler that returns a different WebEngine than the main one
2. The main WebEngine sends the load-call to the secondary WebEngine
3. Register a LocationChangeListener on the secondary WebEngine and catch the location change (including the address) and open it in our external browser
4. Finally clean up the secondary WebEngine: stop loading & unload the URL

I implemented it so the secondary WebEngine is initialized lazy. It may also be initialized in the constructor. Both has pros and contras.

Note: This only triggers for Links which open as a popup. This usually is the case when an a-element has a target-attribute that is not "_self" or with JS: window.open(...).

Here is the Magic ...

Register it like this:

engine.setCreatePopupHandler(new BrowserPopupHandler());

The core class:

public static class BrowserPopupHandler implements Callback<PopupFeatures, WebEngine>
{

    private WebEngine popupHandlerEngine;

    public WebEngine call(PopupFeatures popupFeatures)
    {
        // by returning null here the action would be canceled
        // by returning a different WebEngine (than the main one where we register our listener) the load-call will go to that one
        // we return a different WebEngine here and register a location change listener on it (see blow)
        return getPopupHandler();
    }

    private WebEngine getPopupHandler()
    {
        if (popupHandlerEngine == null) // lazy init - so we only initialize it when needed ...
        {
            synchronized (this) // double checked synchronization
            {
                if (popupHandlerEngine == null)
                {
                    popupHandlerEngine = initEngine();
                }
            }
        }
        return popupHandlerEngine;
    }

    private WebEngine initEngine()
    {
        final WebEngine popupHandlerEngine = new WebEngine();

        // this change listener will trigger when our secondary popupHandlerEngine starts to load the url ...
        popupHandlerEngine.locationProperty().addListener(new ChangeListener<String>()
        {

            public void changed(ObservableValue<? extends String> observable, String oldValue, String location)
            {
                if (!location.isEmpty())
                {
                    Platform.runLater(new Runnable()
                    {

                        public void run()
                        {
                            popupHandlerEngine.loadContent(""); // stop loading and unload the url
                            // -> does this internally: popupHandlerEngine.getLoadWorker().cancelAndReset();
                        }

                    });

                    try
                    {
                        // Open URL in Browser:
                        Desktop desktop = Desktop.getDesktop();
                        if (desktop.isSupported(Desktop.Action.BROWSE))
                        {
                            URI uri = new URI(location);
                            desktop.browse(uri);
                        }
                        else
                        {
                            System.out.println("Could not load URL: " + location);
                        }
                    }
                    catch (Exception e)
                    {
                        e.printStackTrace();
                    }
                }
            }

        });
        return popupHandlerEngine;
    }

}

Answer 3

2017 version - still very hacky but much more concise:

class AboutDialog extends Dialog {
    private final Controller controller;
    private final String url;

    AboutDialog() {
        super();

        this.controller = Controller.getInstance();

        this.setTitle(controller.getProperty("about_title"));
        this.setHeaderText(null);

        this.url = getClass().getResource("/about_dialog.html").toExternalForm();

        this.setWebView();

        this.getDialogPane().getButtonTypes().add(new ButtonType(controller.getProperty("close"), ButtonBar.ButtonData.CANCEL_CLOSE));
        this.getDialogPane().setPrefWidth(600);
    }

    private void setWebView() {
        final WebView webView = new WebView();
        webView.getEngine().load(url);

        webView.getEngine().locationProperty().addListener((observable, oldValue, newValue) -> {
            controller.getMainFxApp().getHostServices().showDocument(newValue);
            Platform.runLater(this::setWebView);
        });

        this.getDialogPane().setContent(webView);
    }
}

Answer 4

Sorry for digging out this old thread but I found another solution that I wanted to share with others who struggle with the same problem. I found a library that has a nice wrapper around the entire issue, see its docs at github.

Edit: Oh, sry for not telling what the project does: The linked library contains a class that actually implemented all of the code discussed in this thread. The user can simply create a new instance of the WebViewHyperlinkListener-interface that gets automatically called when something (mouse enter, mouse quit, mouse click) happens with the link. Once the handler terminates, it returns a boolean: If the handler returns true, the WebView will not navigate to the linked web page. If the handler returns false, it will.

Answer 5

I finally found a working solution that worked for me:

import javafx.beans.value.ChangeListener;
import javafx.beans.value.ObservableValue;
import javafx.concurrent.Worker;
import javafx.scene.web.WebView;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.w3c.dom.events.Event;
import org.w3c.dom.events.EventListener;
import org.w3c.dom.events.EventTarget;
import org.w3c.dom.html.HTMLAnchorElement;

import java.awt.*;
import java.net.URI;

public class HyperLinkRedirectListener implements ChangeListener<Worker.State>, EventListener
{
    private static final String CLICK_EVENT = "click";
    private static final String ANCHOR_TAG = "a";

    private final WebView webView;

    public HyperLinkRedirectListener(WebView webView)
    {
        this.webView = webView;
    }

    @Override
    public void changed(ObservableValue<? extends Worker.State> observable, Worker.State oldValue, Worker.State newValue)
    {
        if (Worker.State.SUCCEEDED.equals(newValue))
        {
            Document document = webView.getEngine().getDocument();
            NodeList anchors = document.getElementsByTagName(ANCHOR_TAG);
            for (int i = 0; i < anchors.getLength(); i++)
            {
                Node node = anchors.item(i);
                EventTarget eventTarget = (EventTarget) node;
                eventTarget.addEventListener(CLICK_EVENT, this, false);
            }
        }
    }

    @Override
    public void handleEvent(Event event)
    {
        HTMLAnchorElement anchorElement = (HTMLAnchorElement) event.getCurrentTarget();
        String href = anchorElement.getHref();

        if (Desktop.isDesktopSupported())
        {
            openLinkInSystemBrowser(href);
        } else
        {
            // LOGGER.warn("OS does not support desktop operations like browsing. Cannot open link '{}'.", href);
        }

        event.preventDefault();
    }

    private void openLinkInSystemBrowser(String url)
    {
        // LOGGER.debug("Opening link '{}' in default system browser.", url);

        try
        {
            URI uri = new URI(url);
            Desktop.getDesktop().browse(uri);
        } catch (Throwable e)
        {
            // LOGGER.error("Error on opening link '{}' in system browser.", url);
        }
    }
}

Usage:

webView.getEngine().getLoadWorker().stateProperty().addListener(new HyperLinkRedirectListener(webView));

Answer 6

When wrapping the d.browse call into a Runnable Object the runtime error never occured again. The strange thing was without that wrapping the ChangeListener was called a second time after some seconds with the same new location and this second call crashed the JVM.