由于ClockListener
是nested class(下),封闭实例(上)可以访问侦听器的私有字段。如果你有一个参考的ClockListener
一个实例,
ClockListener cl = new ClockListener();
,你可以用它来初始化定时器
Timer t = new Timer(1000, cl);
,您可以在您的测试中使用它:
if (cl.count == 2) { t.stop(); }
补遗:作为参考,这是您的程序的一个变体,它使用JToggleButton
来控制计时器。如建议earlier,您曾使用Calendar
来最小化Timer
漂移。和你一样,我放弃了在低分辨率应用中无关的方法。
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();
}
});
}
}
另外,'JPanel'的默认布局是'FlowLayout'。 – trashgod 2011-04-03 10:19:54