jlist

[Jeff Barker]

I am having trouble with a college asignment. I need to fill in the blanks to the code below.

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
public class Lab37B {
JFrame frame;
JList size;
JLabel message;
String[] sizes = {"Small", "Medium", "Large"};
public static void main(String[] args) {
Lab37B me = new Lab37B();
me.go();
}
public void go() {
frame = new JFrame("Change text size");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(300, 200);
size = new JList(__________);
size.set_____________Index(0);
size.add_________________Listener(new SizeListener());
frame.getContentPane().add(size, BorderLayout.WEST);
message = new JLabel("Hello World!", JLabel.CENTER);
message.setFont(new Font("Serif", Font.PLAIN, 12));
frame.getContentPane().add(message);
frame.setVisible(true);
}
class SizeListener implements ListSelectionListener {
public void ______________(ListSelectionEvent e) {
int i = size.get_________Index();
int ptSize = 12 + (12 * i);
message.setFont(new Font("Serif", Font.PLAIN, ptSize));
}
}
}
This (code below)is how I have filled them in. The program will compile but will not run and I can't figur it out. I think the problem is in the line "size = new JList();" But have done everything I can think of trying.
Thanks

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
public class Lab37B {
JFrame frame;
JList size;
JLabel message;
String[] sizes = {"Small", "Medium", "Large"};
public static void main(String[] args) {
Lab37B me = new Lab37B();
me.go();
}
public void go() {
frame = new JFrame("Change text size");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(300, 200);
size = new JList();
size.setSelectedIndex(0);
size.addListSelectionListener(new SizeListener());
frame.getContentPane().add(size, BorderLayout.WEST);
message = new JLabel("Hello World!", JLabel.CENTER);
message.setFont(new Font("Serif", Font.PLAIN, 12));
frame.getContentPane().add(message);
frame.setVisible(true);
}
class SizeListener implements ListSelectionListener {
public void valueChanged(ListSelectionEvent e) {
int i = size.getSelectedIndex();
int ptSize = 12 + (12 * i);
message.setFont(new Font("Serif", Font.PLAIN, ptSize));
}
}
}

[Michael Dunn]

you've missed completing this line

size = new JList(__________);

[Michael Dunn]

Hi Jeff,

responding here to your email.

It is much better if I point you to where you can find the solution,
which will help when researching future problems.

here's a link to the api docs for JList, scroll down to the 'Constructor Summary' section
there a 4 constructors for JList, and one of them matches your requirements.

http://java.sun.com/j2se/1.5.0/docs/api/javax/swing/JList.html

post back if you have a further problem.

might also be worthwhile downloading the api docs, and have them handy on your PC

http://java.sun.com/j2se/1.5.0/download.jsp
(scroll down a bit to "J2SE 5.0 Documentation"), and click the download link