Javafx: button handler in a button handler

Question

Button a=new Button();
...
a.setOnAction(new EventHandler<ActionEvent>()
 {
 public void handle(ActionEvent e)
 {
 Button []b=new Button();
 ...
 }
 }); 

After clicking the button a, the other buttons b will show up. I want to make an event handler for the buttons b. What should I do?

• Mark: I don't understand the question. What's the problem with doing exactly what you want and just creating event handlers for the buttons b?
• fabian: The problem is probably caused by the attempt to assign a Button instance to a Button[] array, which the compiler will tell you in the message for the compilation error.

Answer 1

It's called adding a Node(button) dynamically. You can practice with this approach.

import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
public class JavaFXApplication91 extends Application
{
 int idControl = 0;
 @Override
 public void start(Stage primaryStage)
 { 
 VBox root = new VBox();
 Button btn = new Button();
 btn.setText("Add New Button");
 btn.setId("Button " + idControl);
 btn.setOnAction(new EventHandler<ActionEvent>()
 { 
 @Override
 public void handle(ActionEvent event)
 {
 idControl++;
 Button tempButton = new Button();
 tempButton.setText("Button " + idControl);
 tempButton.setId("Button " + idControl);
 tempButton.setOnAction(new EventHandler<ActionEvent>(){
 @Override
 public void handle(ActionEvent event2)
 {
 System.out.println("You clicked: " + ((Button)event2.getSource()).getId());
 } 
 });
 root.getChildren().add(tempButton); 
 }
 });
 root.getChildren().add(btn);
 Scene scene = new Scene(root, 300, 250);
 primaryStage.setTitle("Hello World!");
 primaryStage.setScene(scene);
 primaryStage.show();
 }
 /**
 * @param args the command line arguments
 */
 public static void main(String[] args)
 {
 launch(args);
 } 
}

This app creates a button on start up. If you click the button it creates a new button. Each new button, when clicked, shows the id of the button being clicked.

Answer 2

You dont have to have a button handler inside a button handler, if the Button b shows up only after clicking Button a, you could add another Button b handler (outside Button a handler), Button b cannot not fire a click event if its not visible