Removing new line function when enter button is pressed Java

Question

Hi

I have a text area that I would like to become blank when the enter button is pressed. I know this would normally be done with a setText method. However when I do this, the text is removed but the new line function created by the return key being pressed. My question is, is the anyway of stopping this default action from happening?

thanks

Answer 1

Hi

I have a text area that I would like to become blank when the enter button is pressed.

This, I understand. Here's how you can do that:

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

public class Main {
    public static void main(String[]args) {
        final JFrame frame = new JFrame();
        final JTextArea area = new JTextArea();
        area.setPreferredSize(new Dimension(200, 200));
        area.addKeyListener(new KeyAdapter(){
            @Override
            public void keyReleased(KeyEvent e) {
                if(e.getKeyCode() == KeyEvent.VK_ENTER) {
                    area.setText("");
                }
            }
        });
        frame.add(area);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setVisible(true);
    }
}

I know this would normally be done with a setText method. However when I do this, the text is removed but the new line function created by the return key being pressed. My question is, is the anyway of stopping this default action from happening?

That, I don't understand.

Answer 2

Are you listening for the ENTER key on the text area and then clearing it? The following works for me:

final JTextArea ta = new JTextArea();
ta.addKeyListener(new KeyListener() {

    @Override
    public void keyTyped(KeyEvent e) {
    }

    @Override
    public void keyReleased(KeyEvent e) {
        if(e.getKeyCode() == KeyEvent.VK_ENTER){
            ta.setText("");
        }
    }

    @Override
    public void keyPressed(KeyEvent e) {
    }
});

Answer 3

The problem is probably that you are not consuming the keystroke event, and although the text area is cleared, the normal processing of the keystroke ends up inserting a newline.

Rather than trapping the keystroke event (which isn't necessarily portable) I would recommend using a DocumentFilter. There is a tutorial here that shows you how to write one. Implement the filter so that when there is a 'newline' in the insert or replace string, replace the entire contents of the document with "".

However this approach can't tell the difference between a newline typed at the keyboard and one pasted into the text area.