Question

I have been trying to make a text changed event handling mechanism for my JTextArea. For my purposes an event has to be fired whenever there is a change in the text of the JTextArea. I tried using the KeyListener interface and here is my code for that.

txtArea.addKeyListener(new KeyListener() {

    @Override
    public void keyTyped(KeyEvent arg0) {

    }

    @Override
    public void keyReleased(KeyEvent arg0) {
        // TODO Auto-generated method stub

    }

    @Override
    public void keyPressed(KeyEvent arg0) {
        currentText = text.getText();
        if (currentText == textString)
            JOptionPane.showMessageDialog(null, "Correct");

    }
});

Nothing happened when the textarea’s text matched the hardcoded text. How can an event changed event be made for this.
Can this objective be achieved with a PropertyChangedListener? If it can, then how?

Answer 1

I would get the JTextArea’s Document via getDocument() (a PlainDocument actually) and use a DocumentListener to listen for changes. This way you’d capture changes from key strokes and also from copy/paste/cut events.