Rendering Canvas with Images - Display is flashing

Question

Hello everybody.
I have created a Canvas within a Frame. This canvas contains many static pictures (.jpg and .png) and static texts. I also print out next to some of these images and static texts some values as strings using drawString.
These values are changed depending on some calculations taking place.
The problem is that the overall GUI is flashing periodically, and it does not look very nice.
How can I render the whole GUI without these flashing problems?
I write down my way:
public class myCanvas extends Canvas implements Runnable
public myCanvas()
//This is a THREAD
        Thread t=new Thread(this);
        t.start(); //start it
public void paint(Graphics g)
        //Static image and static text
        g.drawImage(image2, 1,5, this);
        Font font=new Font("Tahome",Font.BOLD,14);
        g.setFont(font);
        g.drawString("Value:",62,40);
public void update(Graphics g)
        Font font=new Font("Tahome",Font.BOLD,20);
        g.setFont(font);
// I 'd like to update only the values next to static image and static text from paint()
        g.drawString(cntTester+" bpm",148,42);
        cntTester++;
public void run()
        //Firts wait for the images to fully load and paint
        try
            for (int i=0;i<4;i++)
                mediaTracker.waitForID(i);
        catch (Exception ex)
  while (isPlay == true)
            try
                Thread.sleep(2000); //2 secs
            catch(Exception ie)
            this.repaint(140,25,80,25); //Repaint specific sections
        }The above Canvas is instantiated within a Frame.
I really appreciate nay help and guidelines.
Regards,
kalgik

Answer 1

The flashing is really depends on the Thread.sleep() timeout.
import java.awt.*;
public class myCanvas extends Canvas implements Runnable
    //Declaration of variables
    private int cntTester=0; //It used only for test, to update values for parameters
    private MediaTracker mediaTracker;
    private Color colour;
    private Font font14;
    private Font font20;
    private Thread t;
    public myCanvas()
        colour=new Color(0x000000); //-> Black colour for letters
        font14=new Font("Tahome",Font.BOLD,14);
        font20=new Font("Tahome",Font.BOLD,20);
        this.setVisible(true);
        this.setBounds(2,2,235,315);
        init();
        //This is a THREAD
        t=new Thread(this);
        t.start(); //start it
   public void run()
        //First wait for the images to fully load and paint
        try
            for (int i=0;i<1;i++)
                mediaTracker.waitForID(i);
        catch (Exception ex)
        while (isPlay == true)
            try
                Thread.sleep(2000);//The flashing depends on this timeout (2 seconds).
            catch(Exception ie)
            myupdate();
            repaint(500,69,20,170,134); //repaint specific area of Canvas
    //I got rid of the overidden method update(Graphics g)
    public void myupdate()//Graphics g)
        cntTester++; //Simply increment the value of this variable
    public void init()
       mediaTracker = new MediaTracker(this);
        //Image Heart rate
        String imageHeartRateName="Images/Icons/HeartRate/heart-64x64.png";
        imageHeartRate = Toolkit.getDefaultToolkit().createImage(imageHeartRateName);
        mediaTracker.addImage(imageHeartRate, 0);
   public void paint(Graphics g)
        super.paint(g);
        System.out.println("Passing from [paint]");
        g.setColor(colour);
        //Heart rate:
        g.drawImage(this.imageHeartRate, 1,5, this);
        g.setFont(font14);
        g.drawString("Heart Rate:",62,40);//String , coordinates
        g.setFont(font20);
        g.drawString(cntTester+" bpm",148,42);//String , coordinates
}