Java 刷新的日期

Question

我想在 JFrame 中显示 java.util.Date，并且始终刷新以查看新日期。

package pro;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JOptionPane;
import javax.swing.Timer;

public class Date {

public static Timer t;


public static void main(String [] args){

    time();

}
public static Timer time(){

t = new Timer(1000, new ActionListener(){

@SuppressWarnings("deprecation")

@Override
public void actionPerformed(ActionEvent arg0) {
// TODO Auto-generated method stub
JOptionPane.showMessageDialog(null, new java.util.Date().toGMTString());

        }

    });     

    t.setRepeats(true);

    t.start();

    return t;
}
}

我想我在计时器方法中犯了一些错误

我也尝试过编辑它

package pro;

import java.awt.FlowLayout;
import java.util.Date;
import javax.swing.JFrame;
import javax.swing.JLabel;

public class date {

private static JLabel l;
private static Date d = new Date();
private static JFrame f;

@SuppressWarnings("deprecation")

public static void main(String [] args){

    f = new JFrame("Date program");

    f.setVisible(true);
    f.pack();
    f.revalidate();
    f.setLayout(new FlowLayout(FlowLayout.LEFT));
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    l = new JLabel(d.toGMTString());


    f.add(l);
    while(true){

    l.revalidate();

    }
}

}

任何回复将不胜感激。

Answer 1

"when I just write it like this it gets the date in the second I run it without being changed."

只需将 JLabel 添加到 JOPtionPane 中，并仅更新 Timer 中的 JLabel。不要将 JOptionPane 放在 Timer 代码中。这是一个例子

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Date;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.SwingUtilities;
import javax.swing.Timer;

public class Clock {
    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable(){
            public void run() {
                final Date date = new Date();
                final JLabel timeLabel = new JLabel(date.toString());
                Timer timer = new Timer(1000, new ActionListener(){
                    public void actionPerformed(ActionEvent e) {
                        date.setTime(System.currentTimeMillis());
                        timeLabel.setText(date.toString());
                    }
                });
                timer.start();
                JOptionPane.showMessageDialog(null, timeLabel);
            }
        });
    }
}