JavaFX Modal Confirm Dialog Box Example

modal-dialog.css

/**
 * modal-dialog.css
 * place in same directory as WebViewConfirm.java
 * ensure your build system copies the file to your build output directory
 */

.root {
  -fx-glass-color: rgba(95, 158, 160, 0.9);
}

.modal-dialog {
  -fx-padding: 20;
  -fx-spacing: 10;
  -fx-alignment: center;
  -fx-font-size: 20;
  -fx-background-color: linear-gradient(to bottom, derive(-fx-glass-color, 20%), -fx-glass-color);
  -fx-border-color: derive(-fx-glass-color, -20%);
  -fx-border-width: 5;
  -fx-background-insets: 12;
  -fx-border-insets: 10;
  -fx-border-radius: 6;
  -fx-background-radius: 6;
}

.modal-dialog:pressed {
  -fx-cursor: move;
}

.modal-dialog .button:pressed {
  -fx-cursor: default;
}

ModalConfirmExample.java

import javafx.application.Application;
import javafx.beans.value.*;
import javafx.concurrent.Worker;
import javafx.event.*;
import javafx.scene.*;
import javafx.scene.control.*;
import javafx.scene.effect.BoxBlur;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.*;
import javafx.scene.paint.Color;
import javafx.scene.web.WebView;
import javafx.stage.*;

/**
 * Demonstrates a modal confirm box in JavaFX.
 * Dialog is rendered upon a blurred background.
 * Dialog is translucent.
 */
public class ModalConfirmExample extends Application {
  public static void main(String[] args) { launch(args); }
  @Override public void start(final Stage primaryStage) {
    // initialize the stage
    primaryStage.setTitle("Modal Confirm Example");
    final WebView webView = new WebView(); webView.getEngine().load("http://docs.oracle.com/javafx/");
    primaryStage.setScene(new Scene(webView));
    primaryStage.show();

    // initialize the confirmation dialog
    final Stage dialog = new Stage(StageStyle.TRANSPARENT);
    dialog.initModality(Modality.WINDOW_MODAL);
    dialog.initOwner(primaryStage);
    dialog.setScene(
      new Scene(
        HBoxBuilder.create().styleClass("modal-dialog").children(
          LabelBuilder.create().text("Will you like this page?").build(),
          ButtonBuilder.create().text("Yes").defaultButton(true).onAction(new EventHandler<ActionEvent>() {
            @Override public void handle(ActionEvent actionEvent) {
              // take action and close the dialog.
              System.out.println("Liked: " + webView.getEngine().getTitle());
              primaryStage.getScene().getRoot().setEffect(null);
              dialog.close();
            }
          }).build(),
          ButtonBuilder.create().text("No").cancelButton(true).onAction(new EventHandler<ActionEvent>() {
            @Override public void handle(ActionEvent actionEvent) {
              // abort action and close the dialog.
              System.out.println("Disliked: " + webView.getEngine().getTitle());
              primaryStage.getScene().getRoot().setEffect(null);
              dialog.close();
            }
          }).build()
        ).build()
        , Color.TRANSPARENT
      )
    );
    dialog.getScene().getStylesheets().add(getClass().getResource("modal-dialog.css").toExternalForm());

    // allow the dialog to be dragged around.
    final Node root = dialog.getScene().getRoot();
    final Delta dragDelta = new Delta();
    root.setOnMousePressed(new EventHandler<MouseEvent>() {
      @Override public void handle(MouseEvent mouseEvent) {
        // record a delta distance for the drag and drop operation.
        dragDelta.x = dialog.getX() - mouseEvent.getScreenX();
        dragDelta.y = dialog.getY() - mouseEvent.getScreenY();
      }
    });
    root.setOnMouseDragged(new EventHandler<MouseEvent>() {
      @Override public void handle(MouseEvent mouseEvent) {
        dialog.setX(mouseEvent.getScreenX() + dragDelta.x);
        dialog.setY(mouseEvent.getScreenY() + dragDelta.y);
      }
    });

    // show the confirmation dialog each time a new page is loaded.
    webView.getEngine().getLoadWorker().stateProperty().addListener(new ChangeListener<Worker.State>() {
      @Override public void changed(ObservableValue<? extends Worker.State> observableValue, Worker.State state, Worker.State newState) {
        if (newState.equals(Worker.State.SUCCEEDED)) {
          primaryStage.getScene().getRoot().setEffect(new BoxBlur());
          dialog.show();
        }
      }
    });
  }

  // records relative x and y co-ordinates.
  class Delta { double x, y; }
}

This code is now quite old and uses deprecated API features. Before using this code, I recommend reading the answer to the StackOverflow question Block program execution until user clicks button and considering adopting one of the solutions recommended in that answer.

Standard Dialog classes added will be added to JavaFX as part of Java 8u40. See the fxexperience post on bringing dialogs to JavaFX.