Re: adding canvas to applet

Question

Hi
I am trying to add a canvas to an applet. I am successful in doing so. There is a JMenuBar added to the applet. when I click on the file menu The contents are being displayed behind the canvas and as a result I am neither able to see the buttons nor select them. Could some one help me with this.
Note: Once you compile the code you wouldn't be able to see the contents right away. Click on left top,immidiately below the applet menu. This will repaint the contentpane. This is some thing I am working on.
applet class
package aple;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Shape;
import java.awt.geom.AffineTransform;
import java.util.ArrayList;
import javax.swing.JApplet;
public class NewJApplet extends JApplet{
    public Graphics2D g2;
    AffineTransform atf = new AffineTransform();
    sketch sk = new sketch();   
        @Override
    public void init() {      
        getContentPane().add(sk);
       Gui gui = new Gui();
        // menubar
        this.setJMenuBar(gui.Gui());     
    @Override
gui class
package aple;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
public class Gui {
    JMenuBar menuBar;
    JMenu file,edit,insert,view,draw,circle;
    JMenuItem nu,close,saveAs,open,centreandradius,line,rectangle,point,arc;
    public JMenuBar Gui(){
        //Menubar
        menuBar = new JMenuBar();
        //Menus
        file = new JMenu("File");
        menuBar.add(file);
        edit = new JMenu("Edit");
        menuBar.add(edit);
        view = new JMenu("View");
        menuBar.add(view);
        insert = new JMenu("Insert");       
        draw = new JMenu("Draw");
        circle = new JMenu("Circle");
        draw.add(circle);
        insert.add(draw);       
        menuBar.add(insert);
        //MenuItems
        nu = new JMenuItem("New");
        file.add(nu);
        open = new JMenuItem("Open");
        file.add(open);
        saveAs = new JMenuItem("SaveAs");
        file.add(saveAs);
        close = new JMenuItem("Close");
        file.add(close);
        line = new JMenuItem("Line");
        draw.add(line);
        centreandradius = new JMenuItem("Centre and Radius");
        circle.add(centreandradius);
        rectangle = new JMenuItem("Rectangle");
        draw.add(rectangle);
        point = new JMenuItem("Point");
        draw.add(point);
        arc = new JMenuItem("arc");
        draw.add("Arc");
        return(menuBar);
sketch class
package aple;
import java.awt.Canvas;
import java.awt.Color;
import java.awt.Graphics;
public class sketch extends Canvas{
    public void sketch(){
        this.setBackground(Color.green);
    @Override
    public void paint(Graphics g){
     // g.fillRect(50,50, 50, 50); 
}

Answer 1

When you were using JPanel, your "setBackground" didn't work because you were overriding its paint(Graphics) method without calling "super.paint(g);". If you don't do this, the panel won't paint its background.
You should also override "protected void paintComponent(Graphics g)" in any JComponent, such as JPanel, instead of just "paint(Graphics)". (And don't forget to call super.paintComponent(g) FIRST in your subclass's overridden method, if you want the background painted):
class MyJPanelSubclass extends JPanel {
   protected void paintComponent(Graphics g) {
      super.paintComponent(g); // Paints background and any other stuff normally painted.
      // Do your custom painting here.
}