Swing and Thread: repaint : Swing Thread « Threads « Java

Swing and Thread: repaint

Swing and Thread: repaint

import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.Font;
import java.lang.reflect.InvocationTargetException;
import java.text.DecimalFormat;

import javax.swing.BorderFactory;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.SwingConstants;
import javax.swing.SwingUtilities;

public class DigitalTimer extends JLabel {
  private volatile String timeText;

  private Thread internalThread;

  private volatile boolean noStopRequested;

  public DigitalTimer() {
    setFont(new Font("SansSerif", Font.BOLD, 16));
    setText("00000.0"); // use to size component

    timeText = "0.0";

    noStopRequested = true;
    Runnable r = new Runnable() {
      public void run() {
        try {
        } catch (Exception x) {

    internalThread = new Thread(r, "DigitalTimer");

  private void runWork() {
    long startTime = System.currentTimeMillis();
    int tenths = 0;
    long normalSleepTime = 100;
    long nextSleepTime = 100;
    DecimalFormat fmt = new DecimalFormat("0.0");

    Runnable updateText = new Runnable() {
      public void run() {

    while (noStopRequested) {
      try {

        long currTime = System.currentTimeMillis();
        long elapsedTime = currTime - startTime;

        nextSleepTime = normalSleepTime
            + ((tenths * 100) - elapsedTime);

        if (nextSleepTime < 0) {
          nextSleepTime = 0;

        timeText = fmt.format(elapsedTime / 1000.0);
      } catch (InterruptedException ix) {
        // stop running
      } catch (InvocationTargetException x) {

  public void stopRequest() {
    noStopRequested = false;

  public boolean isAlive() {
    return internalThread.isAlive();

  public static void main(String[] args) {

    JFrame f = new JFrame();
    f.getContentPane().setLayout(new FlowLayout());
    f.getContentPane().add(new DigitalTimer());
    f.setSize(250, 100);


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