javafx点击鼠标出现弹窗，demo

在学习javafx的过程中，不知道怎么出现一个弹窗，如，点击一个按钮出现一个修改信息的列表选项

终于在javafx文档示例中发现了类似的东西，记录一下，备忘
package demo9_button;

import javafx.application.Application;
import static javafx.application.Application.launch;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;


public class Test extends Application {
    
    @Override
    public void start(Stage primaryStage) {
        //button一个----------------------------------   
       final Button b2 = new Button("  O K  ");
        
        b2.setOnAction(new EventHandler() {//鼠标点击
            public void handle(ActionEvent e) {
                   Stage stage = new Stage();
                   Label l = new Label("显示出来了");
                   Scene s = new Scene(l,200,100);
                   stage.setScene(s);
                   stage.show();
            }
        });
        StackPane root = new StackPane();
        root.getChildren().add(b2);
        
        Scene scene = new Scene(root, 500, 350);
        
        primaryStage.setTitle("Hello World!");
        primaryStage.setScene(scene);
        primaryStage.show();
    }
    public static void main(String[] args) {
        launch(args);
    }
}