JFrame / JPanel不更新重新绘制或重新验证

Question

Im trying to update my panel once each second but i don't get it to work. i tried almost everything even using revalidate and repaint but it still doesn't work. What am i doing wrong?

The code for refreshing each second and getting te time does work perfectly but i only cant get it to work with the GUI. It only appears once and after that i wont update anymore. This is how it looks like

Here is my JFrame code..

public class MainFrame extends JFrame{
WeatherWidget weatherWidget = new WeatherWidget();
DateTimeWidget dateTimeWidget = new DateTimeWidget();

Timer weatherRefreshTimer = new Timer(1000*60, new ActionListener() {
    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == weatherRefreshTimer){
           // weatherWidget.retreatWeatherInformation();
            weatherWidget.updateWeatherUI();
            repaint();
            System.out.println("Updated weather");
        }
    }
});


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

    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == dateTimeRrefreshTimer){

            dateTimeWidget.retreatDateTimeInformation();
            dateTimeWidget.updateDateTimeUI();

            repaint();
            System.out.println("Updated Time and Date");
        }
    }
});

public MainFrame(){
    this.setSize(540, 950);
    this.getContentPane().setBackground(new Color(0,0,0));
    this.setDefaultCloseOperation(EXIT_ON_CLOSE);
    this.getContentPane().setLayout(null);
    this.setResizable(false);

    addWeatherComponents();
    addDateTimeComponents();

    this.setVisible(true);

    weatherRefreshTimer.start();
    dateTimeRrefreshTimer.start();
}

public void addWeatherComponents(){
    this.add(weatherWidget.getWeerIconLabel());
    this.add(weatherWidget.getTemperatureLabel());
    this.add(weatherWidget.getPlaatsLabel());
}

public void addDateTimeComponents(){
    this.add(dateTimeWidget.getTimeLabel());
}

public void repaint(){
    this.getContentPane().revalidate();
    this.getContentPane().repaint();
}


}

And this is where i have my JLabels

public class DateTimeWidget {
private String time;
private String date;

private int hour;
private int minutes;
private int seconds;
private int day;
private int month;
private int year;

private JLabel timeLabel;
private JLabel dateLabel;

public DateTimeWidget(){
    retreatDateTimeInformation();
    updateDateTimeUI();
}

public void updateDateTimeUI(){
    timeLabel = new JLabel();
    timeLabel.setText(time);
    timeLabel.setBounds(350, 10, 200, 30);
    timeLabel.setForeground(new Color(255,255,255));
    timeLabel.setHorizontalAlignment(SwingConstants.LEFT);
    timeLabel.setBackground(new Color(Transparency.TRANSLUCENT));
    timeLabel.setFont(new Font("Tahoma", Font.BOLD, 30));
    timeLabel.setOpaque(false);

}

public void retreatDateTimeInformation(){
    LocalDateTime now = LocalDateTime.now();
    hour = now.getHour();
    minutes = now.getMinute();
    seconds = now.getSecond();
    day = now.getDayOfMonth();
    month = now.getMonthValue();
    year = now.getYear();

    time =    Integer.toString(hour)+":"+Integer.toString(minutes)+":"+Integer.toString(seconds);

    System.out.println(time);

}

public JLabel getTimeLabel() {
    return timeLabel;
}
}

Answer 1

public void updateDateTimeUI(){
    timeLabel = new JLabel();
    timeLabel.setText(time);
    timeLabel.setBounds(350, 10, 200, 30);
    timeLabel.setForeground(new Color(255,255,255));
    timeLabel.setHorizontalAlignment(SwingConstants.LEFT);
    timeLabel.setBackground(new Color(Transparency.TRANSLUCENT));
    timeLabel.setFont(new Font("Tahoma", Font.BOLD, 30));
    timeLabel.setOpaque(false);

}

Don't keep creating new components!!!

The label should be created once and added to the frame once.

Then when the Timer fires to change the data you simply invoke:

timeLabel.setText(....);

in the ActionListener code (after you determine the new date/time).

Also, there is no need for the if statement in the Timer ActionListener. The listener is only added to one Timer so the code will only be executed when the Timer fires.