Avoiding the repaint of all components in an JApplet

Question

Hello everyone,
Thannks to all who gave me advices for the two JComboBoxes I had...finally I found two "if" conditions in the actionPerformed of the first JComboo which restricted the list of elements posted in the second one.
I have a much bigger problem now....The Applet contains an object which is an extension of JPanel, and in this extension there is a "paintComponent()" that creates a certain number of JButtons in a "for" loop. The problem I have is :
How could I avoid this panel to be repainted every time the page containing the Applet is resized? Is it even possible( because from what I've been reading a "paint()" of the applet always calls for all the components' "repaint()".....I haven't even definned a "paint()" for the applet, .....and then, each button has an action listener that simply won't work after a repaint() of the whole applet. And honestly i'm starting to lose my mind a bit over all this......Oh, I had almost forgotten....the problem after re-sizing is that within the borders of the Panel there are always buttons created by the "for" loop ....and they are smaller and appear high up "north" in the panel...it's horrible!!!!!
This is my code for the paintComponent() of the extension of the JPanel:
public void paintComponent(Graphics g){
       g.drawLine (130,50,130,450);
       g.drawLine (129,50,129,450);
       g.drawLine (270,50,270,450);
       g.drawLine (271,50,271,450);
       g.drawString("Plateau no.", 80,40);
       g.setColor(ballon);
       g.fillArc(100,434,200,100,45,-270);
       System.out.println("I've been through paint");
    for(int i=0;i<13;i++)
       System.out.println("buton ok"+i);
       plateaux=new JButton();
plateaux[i].setEnabled(true);
plateaux[i].addActionListener(this);
Color cri=new Color(240-15*i,0,0);
plateaux[i].setBounds(130,60+30*i,139,15);
plateaux[i].setBackground(cri);
add(plateaux[i], null);
g.drawString(" "+ (13-i),105,70+30*i);
There's nothing else in the extension....only the paint ...it implements ActionListener.....
Thankx in advance....I'd really apreciate it if someone could help me.....
Ruxi

Answer 1

To clear the background for each repaint add a call to super or use clearRect or fillRect (with the background color set, of course). If you don't do this you will get artifacts in your graphics.
class GraphicComponent extends JPanel {
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        // carry on...
}Paint code is the place to render graphics and images, not for adding components. Add your components to the GUI in or via init. Generally is is useful to keep your drawing component separate from your other components.
class GUIClass extends JApplet implements ActionListener {
    public void init() {
        JPanel buttonPanel = getButtonPanel();
        getContentPane().setLayout(new BorderLayout());
        getContentPane().add(buttonPanel, "South");
        getContentPane().add(new GraphicComponent());  // default center section
    private JPanel getButtonPanel() {
        JPanel panel = new JPanel(null);
        JButton[] plateaux = nw JButton[13];
        for(int i=0;i<plateaux.length;i++) {
            System.out.println("buton ok"+i);
            plateaux=new JButton("button " + i);
plateaux[i].setEnabled(true);
plateaux[i].addActionListener(this);
Color cri=new Color(240-15*i,0,0);
plateaux[i].setBounds(130,60+30*i,139,15);
plateaux[i].setBackground(cri);
panel.add(plateaux[i]);