Java Swing: How to get TextArea value including the char just typed?

Question

What\'s the best way to get a value of a TextArea after a key is typed, including this character?

If I do it in the even listener, textarea.getText() return

Answer 1

Have you considered a document listener? possibly armed by the typing event?

class TheListener implements DocumentListener, KeyListener {
  boolean armed;

  void keyPressed(KeyEvent ignore) { }
  void keyReleased(KeyEvent ignore) { }
  void keyTyped(KeyEvent e) {
    armed = true;
    SwingUtilities.invokeLater(new Runnable() { public void run() {
      armed = false;
    }
  }

  void deleteUpdate(DocumentEvent e) {
    changeUpdate(e);
  }
  void insertUpdate(DocumentEvent e) {
    changeUpdate(e);
  }
  void changedUpdate(DocumentEvent e) {
    if (armed) {
      String s = ((JTextComponent)e.getSource()).getText();
      //.... whatever you want to do now
    }
  }
}

//...
TheListener aListener = new TheListener();
textArea.addKeyListener(aListener);
textArea.getDocument().addDocumentListener(aListener);

The theory is to arm the document change listener on a key typed, then add an EDT event to disarm it. The document changes will occur first before disarmed. Once armed, you can assume that any document changes were caused in some part by the key typing event. (warning, I haven't compiled this code, YMMV).