JavaFX如何实现模态窗口

       JavaSE中，使用JOptionPane.show***window可以生产模态的对话框窗口，即用户必须点击对话框的按钮后，才能返回主窗口继续操作，否则无法进行其他操作。但是JavaFX
897d
中没有提供类似JOptionPane的静态类来生成弹出的对话框窗口，若自己写的话，应该如何实现模态呢？

       下面是一个实现dialog box：

import javafx.stage.*;
import javafx.scene.*;
import javafx.scene.paint.Color;
import javafx.scene.control.*;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;

public class ModalDialog {
Button btn;
public ModalDialog(final Stage stg) {
btn = new Button();

final Stage stage = new Stage();
//Initialize the Stage with type of modal
stage.initModality(Modality.APPLICATION_MODAL);
//Set the owner of the Stage
stage.initOwner(stg);
stage.setTitle("Top Stage With Modality");
Group root = new Group();
Scene scene = new Scene(root, 300, 250, Color.LIGHTGREEN);

btn.setOnAction(new EventHandler<ActionEvent>() {

public void handle(ActionEvent event) {
stage.hide();

}
});

btn.setLayoutX(100);
btn.setLayoutY(80);
btn.setText("OK");

root.getChildren().add(btn);
stage.setScene(scene);
stage.show();

}

}

import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.paint.Color;
import javafx.stage.Stage;

public class ModalTest extends Application {

/**
* @param args the command line arguments
*/
public static void main(String[] args) {
Application.launch(ModalTest.class, args);
}

@Override
public void start(final Stage primaryStage) {
primaryStage.setTitle("Hello World");
Group root = new Group();
Scene scene = new Scene(root, 500, 450, Color.LIGHTBLUE);
Button btn = new Button();
btn.setLayoutX(250);
btn.setLayoutY(240);
btn.setText("Show modal dialog");
btn.setOnAction(new EventHandler<ActionEvent>() {

public void handle(ActionEvent event) {
ModalDialog md = new ModalDialog(primaryStage);

}
});
root.getChildren().add(btn);
primaryStage.setScene(scene);
primaryStage.show();
}
}