Adding dynamic components

Question

i have a frame cannot be resized. i have used box layout as the top level layout and on that i have used five panels with components having gridbag layout. Out of five panel one panel has set visible false, which is suppsed to get visible on the trigger of a Button.
Problem : When i m clicking the button i m setting the visibility of the panel as true... but the panel is not showing on the screen(ideally should automatically get adjusted in the screen). i have done validate(). the problem which i could fig out was that its not getting adjusted in the given size as the resizable option of the frame is set to false. Now if i increase the size of the window dynamically i m able to see the component but i m get a flicking effect in the frame. Please ... suggest me some solution that enable me to add a panel in a frame that has a rezibale switched off.
or some way by which i can setsize the frame , add the component without a flickering effect.

Answer 1

example code:
import java.awt.event.*;
import java.awt.*;
import java.util.Vector;
public class AvoidFlicker extends Panel
implements MouseMotionListener, MouseListener
   Vector lines = new Vector();
   int x, y;
   public AvoidFlicker()
      addMouseMotionListener (this);
      addMouseListener(this);
   public void mouseClicked  (MouseEvent e) { }
   public void mouseEntered  (MouseEvent e) { }
   public void mouseExited   (MouseEvent e) { }
   public void mouseMoved    (MouseEvent e) { }
   public void mouseReleased (MouseEvent e) { }
   public void mousePressed  (MouseEvent e)
      x = e.getX();
      y = e.getY();
   public void mouseDragged (MouseEvent e)
      lines.addElement (new Rectangle (x, y, e.getX(), e.getY()));
      x = e.getX();
      y = e.getY();
      repaint();
   protected void paintBackground (Graphics g)
      Dimension size = getSize();
      for (int y = 0; y < size.height; y += 2)
         int blue = 255 - (y % 256);
         Color color = new Color (255, 255, blue);
         g.setColor (color);
         g.fillRect (0, y, size.width, 2);
   public void paintForeground (Graphics g)
      g.setColor (Color.black);
      int numberOfPoints = lines.size();
      for (int i = 0; i < numberOfPoints; i++)
         Rectangle p = (Rectangle) lines.elementAt (i);
         g.drawLine (p.x, p.y, p.width, p.height);
   public void paint (Graphics g)
      paintBackground (g);
      paintForeground (g);
   public void update (Graphics g)
      // override to not clear the background first
      // paint (g);
      paintForeground (g);
   public static void main (String[] args)
      AvoidFlicker panel = new AvoidFlicker();
      Frame f = new Frame ("Avoiding Flicker");
      f.add ("Center", panel);
      f.setSize (300, 300);
      f.show();
}