[英]no luck with javax timer with Jlabel
我仍然無法使用計時器更新JLabel。 我似乎無法弄清楚我所缺少的。 全局第二個變量保持為零,所以我猜計時器正在工作,但沒有更新GUI窗口嗎?
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
class Globals
{
public static int seconds = 0;
}
class main
{
public static void main(String Args[])
{
//text timeline = new text();
JFrame testing = new JFrame();
frame textdes = new frame();
testing.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
testing.setSize(1000,1000);
testing.setVisible(true);
Countdown timer = new Countdown();
Timer countdown = new Timer(5000, timer);
countdown.start();
JLabel countdowntext = new JLabel();
countdowntext.setText("Now its :" + Globals.seconds);
testing.add(countdowntext);
testing.add(textdes);
}
}
class frame extends JFrame
{
class Countdown implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
Globals.seconds++;
}
}
}
您只需在程序中設置一次標簽文本。 然后,計時器更改變量的值,但不對標簽執行任何操作。 它應該做:
Globals.seconds++;
countdowntext.setText("Now its :" + Globals.seconds);
這是一個完整的示例:
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
class Globals {
public static int seconds = 0;
}
class Main {
public static void main(String Args[]) {
//text timeline = new text();
JFrame testing = new JFrame();
testing.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
testing.setSize(1000,1000);
testing.setVisible(true);
JLabel countDownLabel = new JLabel();
countDownLabel.setText("Now it's : " + Globals.seconds);
testing.add(countDownLabel);
CountDown countdown = new CountDown(countDownLabel);
Timer timer = new Timer(5000, countDown);
timer.start();
}
}
class CountDown implements ActionListener {
private JLabel countDownLabel;
public CountDown(JLabel countDownLabel) {
this.countDownLabel = countDownLabel;
}
@Override
public void actionPerformed(ActionEvent e) {
Globals.seconds++;
this.countDownLabel.setText("Now it's : " + Globals.seconds);
}
}
嘗試這個 -
public class MainFrame{
JFrame frame = new JFrame("Main frame");
JPanel panel = new JPanel();
JLabel countdownText = new JLabel();
int seconds = 0;
public MainFrame() {
Timer timer = new Timer(5000, new Countdown());
timer.start();
panel.add(countdownText);
frame.getContentPane().add(panel);
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.setPreferredSize(new Dimension(320,240));
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
countdownText.setText("Now its :" + seconds);
}
class Countdown implements ActionListener {
public void actionPerformed(ActionEvent e) {
seconds++;
countdownText.setText("Now its :" + seconds);
}
}
public static void main(String [] args){
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
new MainFrame();
}
});
}
}
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