Question

I’m trying to make an applet which I can simply drag an image. And I want image object to listen events. So here is the applet code which simple run in a thread:

import java.awt.*;
import java.net.URL;
import javax.swing.JApplet;

public class Client extends JApplet implements Runnable {
    private static final long serialVersionUID = 1L;
    MediaTracker mediaTracker;
    Image [] imgArray;
    Tas t1;

    public void init() 
    { 
        mediaTracker = new MediaTracker(this);
        imgArray = new Image[1];

        URL base = getCodeBase(); 
        imgArray[0] = getImage(base,"okey.png");
        mediaTracker.addImage(imgArray[0],1);

        try {
            mediaTracker.waitForAll();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

        t1 = new Tas(this, new Rectangle(0, 0, imgArray[0].getWidth(this), imgArray[0].getHeight(this)), imgArray[0]);

        Thread t = new Thread(this);
        t.start();
    }

    public void paint(Graphics g) 
    {
        t1.paint(g);
    }

    @Override
    public void run() {
        while(true){
            //System.out.println("run");
            repaint();
            try {
                Thread.sleep(200);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}

And the class of object which holds image is:

import java.awt.Graphics;
import java.awt.Image;
import java.awt.Rectangle;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import javax.swing.JPanel;

@SuppressWarnings("serial")
public class Movable extends JPanel implements MouseListener {

public Client mainObj;
public Rectangle rect;
public Image image;

public Movable(Client mainObj, Rectangle rect, Image image) {
    this.mainObj = mainObj;
    this.rect = rect;
    this.image = image;
    addMouseListener(this);
}

public void paint(Graphics g) {
    g.drawImage(image, rect.x, rect.y, rect.width, rect.height, this);
}

@Override
public void mouseClicked(MouseEvent arg0) {
    System.out.println("clicked");
}

@Override
public void mouseEntered(MouseEvent arg0) {

}

@Override
public void mouseExited(MouseEvent arg0) {

}

@Override
public void mousePressed(MouseEvent arg0) {
    System.out.println("pressed");
}

@Override
public void mouseReleased(MouseEvent arg0) {

}
}

@SuppressWarnings("serial")
class Tas extends Movable{
    public String name = "";

    public Tas(Client mainObj, Rectangle rect, Image image) {
        super(mainObj, rect, image);
    }


}

I can see the image in my applet but nothing happens when I click in or out of the image. So what’s wrong with this code.

Answer 1

Assuming that Tas in code #1 is Moveable in code #2…

You don’t actually use the Moveable as a Component, but instead ask it to paint itself onto the Applet’s graphics context, here:

public void paint(Graphics g) 
{
    t1.paint(g);
}

Instead you should add an instance of Moveable onto the Applet’s container, wherein painting will become automatic, and it will start to receive mouse events. You can also remove that paint() method then too.