Актуализиране на етикет от отделна нишка

Съвсем наскоро взех Java и работя върху приложение за отчитане на времето (всички имаме онези страховити таблици за време, които трябва да попълваме в наши дни...).

Напредвам добре и намирам Window Builder в Eclipse за доста страхотен, но бях напълно объркан от последното нещо в моя списък със задачи. Опитвам се да актуализирам етикет в потребителския интерфейс с времеви низ, който съм изчислил въз основа на начално времево клеймо минус текущо времево клеймо, което се изчислява всяка секунда. Това ще покаже колко време отнема текущата задача.

Това е моят код досега и всичко останало работи освен актуализирането на етикета в потребителския интерфейс. Това е 20 (иш) реда от дъното на кода.

import java.io.FileWriter;
import java.io.IOException;

import javax.swing.*;

import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.TableColumn;
import org.eclipse.swt.widgets.TableItem;
import org.eclipse.swt.SWT;
import org.eclipse.swt.widgets.Text;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.wb.swt.SWTResourceManager;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.events.MouseAdapter;
import org.eclipse.swt.events.MouseEvent;
import org.eclipse.swt.widgets.Table;

public class mainDisplay {
private static Text txtTask;
static boolean timerRunning = false;
static long timePassed = 0;
static long startTime = 0;
static long currTime = 0;
static String timeString = "";

/**
 * Launch the application.
 * @param args
 */

public static String timeString(long timePassed) {
    if(timePassed < 10) {
        timeString = "00:00:0"+String.valueOf(timePassed);
    }
    else if(timePassed < 60 && timePassed >= 10){
        timeString = "00:00:"+String.valueOf(timePassed);
    }
    else if(timePassed >= 60 && timePassed < 600){
        timeString = "00:0" + String.valueOf(timePassed/60) + ":";
        if(timePassed % 60 < 10){
            timeString = timeString + "0"+String.valueOf(timePassed%60);
        }
        else{
            timeString = timeString + String.valueOf(timePassed%60);
        }
    }
    else if(timePassed >= 600 && timePassed < 3600){
        timeString = "00:" + String.valueOf(timePassed/60) + ":";
        if(timePassed % 60 < 10){
            timeString = timeString + "0"+String.valueOf(timePassed%60);
        }
        else{
            timeString = timeString + String.valueOf(timePassed%60);
        }
    }
    else if(timePassed >= 3600 && timePassed < 36000){
        // Hours
        timeString = "0" + String.valueOf(timePassed/3600) + ":";
        // Mins
        if((timePassed%3600)/60 < 10){
            timeString = timeString + "0" + String.valueOf((timePassed%3600)/60) + ":";
        }
        else if((timePassed%3600)/60 >= 10){
            timeString = timeString + String.valueOf((timePassed%3600)/60) + ":";
        }
        // Secs
        if((timePassed%3600)%60 < 10){
            timeString = timeString + "0" + String.valueOf((timePassed%3600)%60);
        }
        else if((timePassed%3600)%60 >= 10){
            timeString = timeString + String.valueOf((timePassed%3600)%60);
        }
    }
    return timeString;
}

public static void main(final String[] args) {
    Display display = Display.getDefault();
    final Shell shlSot = new Shell();
    shlSot.setBackground(SWTResourceManager.getColor(SWT.COLOR_TITLE_BACKGROUND));
    shlSot.setSize(455, 299);
    shlSot.setText("SOT 1.0");

    txtTask = new Text(shlSot, SWT.BORDER);
    txtTask.addMouseListener(new MouseAdapter() {
        @Override
        public void mouseUp(MouseEvent e) {
            txtTask.setText("");
        }
    });
    txtTask.setFont(SWTResourceManager.getFont("Segoe UI", 11, SWT.NORMAL));
    txtTask.setText("Add a task...");
    txtTask.setBounds(10, 62, 198, 27);

    Label lblTitle = new Label(shlSot, SWT.NONE);
    lblTitle.setFont(SWTResourceManager.getFont("Script MT Bold", 22, SWT.BOLD));
    lblTitle.setBackground(SWTResourceManager.getColor(SWT.COLOR_TITLE_BACKGROUND));
    lblTitle.setBounds(45, 15, 175, 37);
    lblTitle.setText("Sands of Time");

    final Table tblTasks = new Table(shlSot, SWT.BORDER | SWT.FULL_SELECTION);
    tblTasks.setBounds(10, 107, 417, 144);
    tblTasks.setHeaderVisible(true);
    tblTasks.setLinesVisible(true);

    TableColumn clmTask = new TableColumn(tblTasks, SWT.NONE);
    clmTask.setText("Task");
    TableColumn clmTime = new TableColumn(tblTasks, SWT.NONE);
    clmTime.setText("Time");

    tblTasks.getColumn(0).pack();
    tblTasks.getColumn(1).pack();

    Label lblHourGlass = new Label(shlSot, SWT.NONE);
    lblHourGlass.setBackground(SWTResourceManager.getColor(SWT.COLOR_TITLE_BACKGROUND));
    lblHourGlass.setFont(SWTResourceManager.getFont("Wingdings", 30, SWT.NORMAL));
    lblHourGlass.setBounds(14, 11, 32, 46);
    lblHourGlass.setText("6");

    final Label lblTimer = new Label(shlSot, SWT.NONE);
    lblTimer.setAlignment(SWT.CENTER);
    lblTimer.setFont(SWTResourceManager.getFont("Segoe UI", 19, SWT.NORMAL));
    lblTimer.setBackground(SWTResourceManager.getColor(SWT.COLOR_TITLE_BACKGROUND));
    lblTimer.setBounds(268, 17, 113, 32);
    lblTimer.setText("00:00:00");

    final Button btnExport = new Button(shlSot, SWT.NONE);
    final Button btnClear = new Button(shlSot, SWT.NONE);
    final Button btnStart = new Button(shlSot, SWT.NONE);
    final Button btnStop = new Button(shlSot, SWT.NONE);

    btnClear.addSelectionListener(new SelectionAdapter() {
        @Override
        public void widgetSelected(SelectionEvent e) {
            int dialogButton = 0;
            // Prompt the user whether to go ahead or not
            int dialogResult = JOptionPane.showConfirmDialog (null, "Are you sure you want to clear all progress?","Warning",dialogButton);
            if(dialogResult == JOptionPane.YES_OPTION){
                // Stop the timer
                timerRunning = false;

                // Clear the timer on the UI
                lblTimer.setText("00:00:00");

                // Enable/Disable buttons and reset text
                btnStop.setEnabled(false);
                btnExport.setEnabled(true);
                btnStart.setEnabled(true);
                txtTask.setEnabled(true);
                txtTask.setText("Add a task...");

                // Empty the list on the UI
                tblTasks.removeAll();
            }
        }
    });
    btnClear.setBounds(370, 63, 57, 25);
    btnClear.setText("Clear");


    btnExport.addSelectionListener(new SelectionAdapter() {
        @Override
        public void widgetSelected(SelectionEvent e) {
            // Export the contents of the list to CSV
            try{
                FileWriter writer = new FileWriter("sotExport.csv");

                writer.append("Task");
                writer.append(',');
                writer.append("Time");
                writer.append('\n');

                TableItem [] items = tblTasks.getItems ();
                for(int i=0; i<items.length; i++) {                     
                    writer.append(items[i].getText(0));
                    writer.append(',');
                    writer.append(items[i].getText(1));
                    writer.append('\n');
                }

                writer.flush();
                writer.close();
            }
            catch(IOException e1){
                 e1.printStackTrace();
            }
        }
    });
    btnExport.setBounds(319, 63, 46, 25);
    btnExport.setText("Export");

    btnStop.addSelectionListener(new SelectionAdapter() {
        @Override
        public void widgetSelected(SelectionEvent e) {
            // Stop button stuff

            // Add contents of txtTask to list
            //lstTasks.add(txtTask.getText());
            TableItem item = new TableItem(tblTasks, SWT.NONE);
            item.setText(0, txtTask.getText());
            item.setText(1, timeString);
            tblTasks.getColumn(0).pack();
            tblTasks.getColumn(1).pack();

            btnStop.setEnabled(false);
            btnClear.setEnabled(true);
            btnExport.setEnabled(true);
            btnStart.setEnabled(true);
            txtTask.setEnabled(true);
            timerRunning = false;
        }
    });
    btnStop.setBounds(267, 63, 46, 25);
    btnStop.setText("Stop");
    btnStop.setEnabled(false);


    btnStart.addSelectionListener(new SelectionAdapter() {
        @Override
        public void widgetSelected(SelectionEvent e) {
            // Update UI options
            btnStop.setEnabled(true);
            btnStart.setEnabled(false);
            txtTask.setEnabled(false);
            btnClear.setEnabled(false);
            btnExport.setEnabled(false);

            // Start timer and update lblTimer
            timerRunning = true;
            startTime = (System.currentTimeMillis() / 1000L);
            System.out.println(startTime);

            new Thread(new Runnable(){ 
                public void run(){ 
                    while (timerRunning){ 
                        // Get current time and calculate timer                     
                        currTime = System.currentTimeMillis() / 1000L;
                        timePassed = currTime - startTime;
                        timeString = timeString(timePassed);

                        try {
                            // Why do you not work?!!?!? >:(
                            lblTimer.setText(timeString);

                            Thread.sleep(1000);
                        } catch (InterruptedException e1) {
                            e1.printStackTrace();
                        }
                    } 
                } 
            }).start();
        }
    });
    btnStart.setBounds(214, 63, 46, 25);
    btnStart.setText("Start");

    shlSot.open();
    shlSot.layout();
    while (!shlSot.isDisposed()) {
        if (!display.readAndDispatch()) {
            display.sleep();
        }
    }
}
}

Когато щракна върху старт, получавам следното изключение;

Exception in thread "Thread-0" org.eclipse.swt.SWTException: Invalid thread access
    at org.eclipse.swt.SWT.error(SWT.java:4397)
    at org.eclipse.swt.SWT.error(SWT.java:4312)
    at org.eclipse.swt.SWT.error(SWT.java:4283)
    at org.eclipse.swt.widgets.Widget.error(Widget.java:472)
    at org.eclipse.swt.widgets.Widget.checkWidget(Widget.java:363)
    at org.eclipse.swt.widgets.Label.setText(Label.java:386)
    at mainDisplay$5$1.run(mainDisplay.java:246)
    at java.lang.Thread.run(Unknown Source)

Не знам защо изключи изключението за първи път, но го има.

Това проблем с нишката ли е? Мога ли да нямам достъп до нишката за показване от моята нова нишка, за да актуализирам етикета? Някаква идея как да го заобиколя?

Благодаря

Стив