Java Applet code works in browser but not in AppletViewer

Question

This applet works fine when I use it in a browser, but why doesn't it work with the applet viewer?

I have tried using both jGRASP and Eclipse to view the applet but whatever I do, I get this:

java.lang.NumberFormatException: null on this line of code

int paramCount = Integer.parseInt( getParameter( "count" ) );

I dont understand why it is doing this.

//file: AppletParameters.java

import javax.swing.JApplet;
import javax.swing.JApplet;
import javax.swing.JPanel;
import javax.swing.JLabel;
import javax.swing.ImageIcon;
import java.awt.GridLayout;

public class AppletParameters extends JApplet
{
    private JPanel panel; // panel to display pictures

    public void init( )
    {
        // get the parameter count from the html 'count' parameter
        int paramCount = Integer.parseInt( getParameter( "count" ) );
        // create an array
        ImageIcon [] image = new ImageIcon[paramCount];
        // get each file name from the html 'file' parameter and put into array
        for ( int k=0; k<paramCount; k++ )
            image[k] = new ImageIcon( getImage( getDocumentBase( ), getParameter( "file"+k ) ) );
        // build a new JPanel with GridLayout
        panel = new JPanel( new GridLayout( 2, 5 ) );
        // add images to the panel
        for ( int k=0; k<paramCount; k++ )
            panel.add( new JLabel( image[k] ) );
        // add panel to me (this applet object)
        add( panel );
    }  // end init method
}  // end class

Hovercraft Full Of Eels · Answer 1 · 2012-09-30T03:48:12.520

1

Are you passing in parameters to the applet via AppletViewer? I doubt you are.

In Eclipse you would do this via the Run menu Run Configurations... sub menu item, then the Parameters tab.

enter image description here

edited Sep 30 '12 at 03:48

answered Sep 30 '12 at 03:41

Hovercraft Full Of Eels

283,665
25
256
373

what parameters would I pass? I found where to pass them but not sure what would go there. Would i pass the "count" and the image files there? – biff_24_2000 Sep 30 '12 at 03:49
@biff: your code tells you exactly what parameters are need. What parameters are you using in the code? There are two of them. – Hovercraft Full Of Eels Sep 30 '12 at 03:53
@biff: even the code comments tell you what parameters you need. But yes you need `count` for the number of images, and `file` for the base name of the image files. Give it a try, as you've got nothing to lose. – Hovercraft Full Of Eels Sep 30 '12 at 03:55
@biff: no biggie. I was just pulling your leg. – Hovercraft Full Of Eels Sep 30 '12 at 04:06

Java Applet code works in browser but not in AppletViewer

1 Answers1