如何停止Java Applet中的图像闪烁？

Question

My problem is that whenever I use a Java Applet I just coded, my png images flicker repeatdly. I have already changed my thread sleep time to smaller, and that does not remove the problem.

Here is the code where I'm calling on the image to be shown:

    public void init(){
    setSize(854, 480);
    Thread th = new Thread(this);
    th.start();
    offscreen = createImage(854,480);
    d = offscreen.getGraphics();
    addKeyListener(this);
}
public void paint(Graphics g){

    g.clearRect(0, 0, 854, 480);
    g.drawImage(background, 0, 0, this);
    d.drawImage(offscreen, 0, 0, this);
    g.drawOval(x, y, 20, 20);
}
public void update(Graphics g){
    paint(g);
}

And this line of code is where I'm declaring the image if you like

    background = ImageIO.read(this.getClass().getResource("background.png"));

Answer 1

The flickering is caused by clearRect.

If your images cover entire applet, you can just remove clearRect call.

If they do not cover, you need to create an offscreen image, make all drawing to it, and then draw offscreen image by drawImage call to your applet.