如何在JDialog上使用JTextArea时使关键事件起作用？

Question

What I have basicly created is a JDialog which has a key event on the form. So when for example space is pressed it does something. This worked fine until I created a JTextArea on the same dialog, which is editable. When I did this I can't remove the focus from the JTextArea and make the hot keys work. How do I allow both the key events and the JTextArea to function on the same JDialog?

Answer 1

Let's assume you already have defined your KeyListener for your JDialog object.

This is how you can get the components of a component:

dialog.getContentPane().getComponents();

This is how you can get the array of KeyListener s of your dialog :

KeyListener[] keyListeners = dialog.getKeyListeners();

Now, let's iterate the Component s and add the KeyListener s:

Component[] components = dialog.getContentPane().getComponents();
KeyListener[] keyListeners = dialog.getKeyListeners();
for (int componentIndex = 0; componentIndex < components.length; componentIndex++) {
    for (int keyListenerIndex = 0; keyListenerIndex < keyListeners.length; keyListenerIndex++) {
        components[componentindex].addKeyListener(keyListeners[keyListenerIndex]);
    }
}

Code is untested, if there are any typos, please, let me know. Also, this is not transitive, that is, it does not dwelve into the listeners of the Component s of Component s, it defines the key events for the child Component s solely.

Answer 2

What you need to do is add the KeyListener from the JDialog to the JTextArea .

Below is a SSCCE of this.

import java.awt.event.*;
import javax.swing.*;

public class DialogListener {

    public static void main(String[] args) {
        JDialog dialog = new JDialog();
        dialog.setSize(300, 400);
        dialog.setVisible(true);

        KeyListener listener = getKeyListener();

        dialog.addKeyListener(listener);

        JTextArea area = new JTextArea();
        area.addKeyListener(listener);

        dialog.add(area);
    }

    public static KeyListener getKeyListener(){
        return new KeyAdapter() {
            public void keyTyped(KeyEvent e) {
                System.out.println(e.getKeyChar());
            }
        };

    }
}