Listen to CaretEvent with CaretListener : CaretListener « Swing Event « Java Tutorial

1. Java Tutorial
2. Swing Event
3. CaretListener

import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.event.CaretEvent;
import javax.swing.event.CaretListener;

public class Main implements ActionListener {
  JTextField jtf = new JTextField(10);

  JButton jbtnGetTextUpper = new JButton("Get Text In Uppercase");

  Main() {
    JFrame jfrm = new JFrame("Demonstrate a Text Field");
    jfrm.setLayout(new FlowLayout());
    jfrm.setSize(240, 140);
    jfrm.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    jtf.setActionCommand("TF");

    jtf.addActionListener(this);
    jbtnGetTextUpper.addActionListener(this);

    jtf.addCaretListener(new CaretListener() {
      public void caretUpdate(CaretEvent ce) {
        System.out.println("Text in real time: " + jtf.getText());
      }
    });

    jfrm.add(jtf);
    jfrm.add(jbtnGetTextUpper);
    jfrm.setVisible(true);
  }

  public void actionPerformed(ActionEvent ae) {
    if (ae.getActionCommand().equals("TF")) {
      System.out.println("ENTER key pressed: " + jtf.getText());
    } else {
      String str = jtf.getText().toUpperCase();
      System.out.println("Button pressed: " + str);
    }
  }

  public static void main(String args[]) {
    new Main();
  }
}

15.8.CaretListener
	15.8.1.	Caret Events and Listeners
	15.8.2.	Listen to CaretEvent with CaretListener