Because ClockListener
is a nested class (lower), the enclosing instance (upper) can access the listener’s private fields. If you have a reference to an instance of ClockListener
,
ClockListener cl = new ClockListener();
you can use it to initialize your timer
Timer t = new Timer(1000, cl);
and you can use it in your test:
if (cl.count == 2) { t.stop(); }
Addendum: For reference, here’s a variation of your program that uses a JToggleButton
to control the timer. As suggested earlier, you had used Calendar
to minimize Timer
drift. Like you, I abandoned the approach as irrelevant in a low-resolution application.
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.JToggleButton;
import javax.swing.Timer;
/** @see https://stackoverflow.com/questions/5528939*/
class ClockExample extends JFrame {
private static final int N = 60;
private static final String stop = "Stop";
private static final String start = "Start";
private final ClockListener cl = new ClockListener();
private final Timer t = new Timer(1000, cl);
private final JTextField tf = new JTextField(3);
public ClockExample() {
t.setInitialDelay(0);
JPanel panel = new JPanel();
tf.setHorizontalAlignment(JTextField.RIGHT);
tf.setEditable(false);
panel.add(tf);
final JToggleButton b = new JToggleButton(stop);
b.addItemListener(new ItemListener() {
@Override
public void itemStateChanged(ItemEvent e) {
if (b.isSelected()) {
t.stop();
b.setText(start);
} else {
t.start();
b.setText(stop);
}
}
});
panel.add(b);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.add(panel);
this.setTitle("Timer");
this.pack();
this.setLocationRelativeTo(null);
this.setVisible(true);
}
public void start() {
t.start();
}
private class ClockListener implements ActionListener {
private int count;
@Override
public void actionPerformed(ActionEvent e) {
count %= N;
tf.setText(String.valueOf(count));
count++;
}
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
ClockExample clock = new ClockExample();
clock.start();
}
});
}
}