Help needed in getting applet working

Question

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class murali1 extends JApplet{
     private Container contain;
     private GridBagLayout grid;
     private GridBagConstraints c;
* Create the GUI and show it.
public murali1() {
          //super("Assignment 1");
//Create and set up the window.
JFrame frame = new JFrame("Assignment 1");
          //Menu
          JMenuBar bar = new JMenuBar();
          JMenu file = new JMenu("File");
          bar.add(file);
          JMenuItem open = new JMenuItem("Open");
          file.add(open);
          open.addActionListener(new ActionListener(){
          public void actionPerformed (ActionEvent e)
          JMenuItem save = new JMenuItem("Save Random");
          file.add(save);
          save.addActionListener(new ActionListener(){
          public void actionPerformed (ActionEvent e)
          JMenuItem exit1 = new JMenuItem("Exit");
          file.add(exit1);
          exit1.addActionListener(new ActionListener(){
          public void actionPerformed (ActionEvent e)
               System.exit(0);
          //Create 4 panels
          JPanel panel1,panel2,panel3,panel4;
          /*Adding components to Panel 1
          Panel 1 contains one Label and a ComboBox
          Panel 1 is a GridLayout
          panel1=new JPanel();
          String method[] = {"Random","Ascending","Descending"};
          JComboBox combo = new JComboBox(method);//Combo Box
          combo.setMaximumRowCount(3);
          combo.addItemListener(new ItemListener(){
          public void itemStateChanged(ItemEvent comboevent)
          JLabel combolabel;
          combolabel = new JLabel("Choose Prioritization Heuristic");
          //panel1.setLayout( new GridLayout (2,1));
          panel1.add(combolabel);
          panel1.add(combo);
          /*Adding components to panel 2
          Panel 2 contains one label and one text area
          Panel 2 is a GridLayout
          panel2 = new JPanel();
          JLabel textlabel = new JLabel("Evaluator Results");
          JTextArea evalarea = new JTextArea();
          panel2.add(textlabel);
          //panel1.setLayout( new GridLayout (2,1));
          panel2.add(evalarea);
          /*Adding components to panel 3
          Panel 3 contains 5 labels,3 textfields, 1 button
          Panel 3 is a GridLayout
          panel3 = new JPanel();
          JLabel label1,label2,label3,label4,label5;
          label1 = new JLabel("Use the Fields only for Random Heuristic");
          label2 = new JLabel("Enter Maximum # of Tries");
          label3 = new JLabel("Enter # of Tests in TS");
          label4 = new JLabel("Enter ID# of Tests in TS(d) (Separated by Comma)");
          label5 = new JLabel("Please Press SUBMIT");
          JTextField tf1,tf2,tf3;
          tf1 = new JTextField();
          tf2 = new JTextField();
          tf3 = new JTextField();
          JButton submit = new JButton("Submit");
          //panel1.setLayout( new GridLayout (9,1));
          panel3.add(label1);
          panel3.add(label2);
          panel3.add(tf1);
          panel3.add(label3);
          panel3.add(tf2);
          panel3.add(label4);
          panel3.add(tf3);
          panel3.add(label5);
          panel3.add(submit);
          /*Adding components to panel 4
          Panel 4 contains 4 labels,1 textfields, 3 button
          Panel 4 is a GridLayout
          panel4 = new JPanel();
          JLabel label6,label7,label8,label9;
          label6 = new JLabel("Press RUN to start evaluation");
          label7 = new JLabel("Press Exit to Terminate Program");
          label8 = new JLabel("MLP(d) and RP(d) are:");
          label9 = new JLabel("Press CLEAR to start new evaluation");
          JButton run = new JButton("Run");
          JButton exit = new JButton("Exit");
          JButton clear = new JButton("Clear");
          JTextArea area1 = new JTextArea();
          panel4.add(label6);
          panel4.add(run);
          panel4.add(label7);
          panel4.add(exit);
          panel4.add(label8);
          panel4.add(area1);
          panel4.add(label9);
          panel4.add(clear);
          /*panel1.setVisible(true);
          panel2.setVisible(true);
          panel3.setVisible(true);
          panel4.setVisible(true);*/
          /* set Grid Bag Layout
          Add all the panels to the GridBag Layout
          contain = frame.getContentPane();
          grid = new GridBagLayout();
          contain.setLayout(new GridBagLayout());
          c = new GridBagConstraints();
          addComponent(panel1,0,0);
          addComponent(panel2,0,4);
          addComponent(panel3,4,0);
          addComponent(panel4,4,6);
          //setSize(1200,100);
          this.setVisible(true);
          /*Method to Add Components*/
          private void addComponent(Component co,int row,int column)
                    c.gridx = column;
                    c.gridy = row;
                    grid.setConstraints(co,c);
                    contain.add(co);
/*Set up the content pane.
addComponentsToPane(frame.getContentPane());*/
//Display the window.
//frame.pack();
//frame.setVisible(true);
public static void main(String[] args) {
murali1 g = new murali1();
               //g.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
The Compliation is totally fine,applet loads, but the gui components are not diaplyed.Any suggestions.
Thank you.

Answer 1

That's not really an applet. Or it's a half-done one. It looks like you just took a standalone app (with its own frame and everything), added "extends JApplet", commented out a few things that absolutely shouldn't work, and otherwise changed almost nothing.
The browser won't invoke the applet's main() method. I guess that's not a problem, but are you aware that it's not being invoked?
An applet is a kind of panel. You shouldn't be creating frames. You should put all the GUI elments in the panel...which it appears you did, but can you actually get rid of the irrelevant code? Furthermore, when you post code on these forums, you should wrap it in [code][/code] tags; it makes it much easier to read.
An applet shouldn't call System.exit(). You'll probably get a security exception if you try running that.
That addComponent method looks suspicious to me. You're changing the columns and row of the same object over and over again. I'm not a GUI expert, so maybe I'm wrong, but that seems really wrong.
You shouldn't need to call this.setVisible(true) for an applet.
I'd suggest cleaning your code up, and maybe moving some of that stuff out of the constructor anyway. In an applet it might be better placed in init().
Message was edited by:
paulcw