import org.w3c.dom.NodeList;
import org.w3c.dom.events.Event;
import org.w3c.dom.events.EventListener;
import org.w3c.dom.events.EventTarget;
import javafx.application.Application;
import javafx.application.Platform;
import javafx.beans.value.ObservableValue;
import javafx.concurrent.Worker;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.layout.Pane;
import javafx.scene.layout.VBox;
import javafx.scene.web.WebView;
import javafx.stage.Stage;
public class JavaFxNpe extends Application {
private final EventListener listener = this::onButtonClicked;
private WebView webView;
public static void main(String[] args) {
launch(args);
}
@Override
public void start(Stage primaryStage) {
primaryStage.setTitle("NPE on WebView event");
Pane root = new VBox();
webView = new WebView();
final Button button = new Button("Open Page");
button.setOnAction(event -> loadWebPage());
root.getChildren().add(button);
root.getChildren().add(webView);
Scene scene = new Scene(root);
primaryStage.setScene(scene);
primaryStage.show();
webView.getEngine().getLoadWorker().stateProperty().addListener(this::onStateChanged);
}
private void loadWebPage() {
webView.getEngine().loadContent(
" Submit Test ");
}
private void onStateChanged(ObservableValue observable,
Worker.State oldState,
Worker.State newState) {
if (newState != Worker.State.SUCCEEDED) {
return;
}
final NodeList nodeList = webView.getEngine().getDocument().getElementsByTagName("button");
for (int i = 0; i < nodeList.getLength(); i++) {
final EventTarget eventTarget = (EventTarget) nodeList.item(i);
eventTarget.addEventListener("click", this.listener, true);
}
}
private void onButtonClicked(Event event) {
// On JFX thead
webView.getEngine().load("about:blank");
// Need to delay the GC to after this event is handled, but we also want a GC before we open
// the page again.
Platform.runLater(System::gc);
}
}