Why isn't it working? :confused:

[ocarabal]

Okay so I was working on some homework and I just completed this assignment, but I can't figure out why I can't get the submit button to work..

import javax.swing.*;
import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.JOptionPane;
import java.text.DecimalFormat;

public class SkateBoardDesigner extends JFrame
{
	private String[] boards = { "The Master Thrasher / $60","The Dictator / $45","The Street King / $50" };
	private String[] axles = { "7.75in axle / $35","8in axle / $40","8.5in axle / $45" };
	private String[] wheels = { "55mm / $20","55mm / $22","58mm / $24","61mm / $28" };
	private String[] misc = { "Grip Tape / $10","Bearings / $30","Riser Pads / $2","Nuts & Bolts kit / $3" };
	private int[][] prices = { {60, 45, 50}, //deck
					  {35, 40, 45}, //assembly
					  {20, 22, 24, 28}, //wheels
					  {10, 30,  2,  3} }; //Misc.

	private int deckPrice, assemblyPrice, wheelPrice, miscPrice=0;
	private int priceSTotal;
	private double priceTax, priceTotal;
	private JLabel name;

	private JPanel titlePanel;
	private JPanel choicePanel;
	private JPanel totalPanel;
	private JPanel bottomPanel;

	private JLabel deck, assembly, whel, mis;
	private JComboBox decks;
	private JComboBox assemblies;
	private JComboBox wheel;
	private JList other;

	private JButton total;

	public SkateBoardDesigner()
	{
		setTitle("Skate Board Designer");
		setSize(300, 270);
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		setLayout(new BorderLayout());

		titlePanel();
		choicePanel();
		totalPanel();

		add(titlePanel, BorderLayout.NORTH);
		add(choicePanel, BorderLayout.CENTER);
		add(totalPanel, BorderLayout.SOUTH);
		setVisible(true);
	}
	public void titlePanel()
	{
		name = new JLabel("The Skate Shop");
		titlePanel = new JPanel();
		titlePanel.add(name);
	}

	public void choicePanel()
	{
		deck = new JLabel("Decks");
		decks = new JComboBox(boards);
		decks.addActionListener(new DeckListener());//deck Listener
		assembly = new JLabel("Truck Assemblies");
		assemblies = new JComboBox(axles);
		assemblies.addActionListener(new AssemblyListener());//AssemblyListener
		whel = new JLabel("     Wheels");
		wheel = new JComboBox(wheels);
		wheel.addActionListener(new WheelListener());//WheelListner
		mis = new JLabel("               Miscellaneous");
		other = new JList(misc);
		other.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);

		choicePanel = new JPanel();
		choicePanel.setLayout(new FlowLayout(FlowLayout.RIGHT));
		choicePanel.add(deck);
		choicePanel.add(decks);
		choicePanel.add(assembly);
		choicePanel.add(assemblies);
		choicePanel.add(whel);
		choicePanel.add(wheel);
		choicePanel.add(mis);
		choicePanel.add(other);
	}

	private class DeckListener implements ActionListener
	{
		public void actionPerformed(ActionEvent e)
		{
			deckPrice = prices[0][decks.getSelectedIndex()];
		}
	}

	private class WheelListener implements ActionListener
	{
		public void actionPerformed(ActionEvent e)
		{
			wheelPrice = prices[1][wheel.getSelectedIndex()];
		}
	}

	private class AssemblyListener implements ActionListener
	{
		public void actionPerformed(ActionEvent e)
		{
			assemblyPrice = prices[1][assemblies.getSelectedIndex()];
		}
	}

	public void totalPanel()
	{
		total = new JButton("Total");
		total.addActionListener(new TotalListener()); //TotalListener

		totalPanel = new JPanel();
		totalPanel.add(total);
	}

	private class TotalListener implements ActionListener
	{
		public void actionPerformed(ActionEvent e)
		{
			int[] selections = other.getSelectedIndices();
			int size = selections.length;
			for (int index = 0; index<=size; index++)
			{
				miscPrice += prices[4][selections[index]];
			}
			priceSTotal = deckPrice+assemblyPrice+wheelPrice+miscPrice;
			priceTax = priceSTotal*.06;
			priceTotal = priceSTotal+priceTax;

			DecimalFormat USCurrency = new DecimalFormat("#,##0.00");
			JOptionPane.showMessageDialog(null, "Sub Total: $"+USCurrency.format(priceSTotal)+"\nTax: $"+USCurrency.format(priceTax)+"\nTotal Price: $"+USCurrency.format(priceTotal));
		}
	}
	public static void main(String[] args)
	{
		new SkateBoardDesigner();
	}
}

[Tolls]

What does "can't get the submit button to work" mean?
You need to be a bit more descriptive, including any exception messages.

[siva_vs_siva]

null pointer arises when you referring undefined values.. so you have to change your code as..

for (int index = 0; index<=size-1; index++)
{
miscPrice += prices[3][selections[index]];
System.out.println(miscPrice);
}

[ocarabal]

ummm, you're going to have to explain what exactly your code means. I'm not following. I don't want to use code without understanding it.

[ocarabal]

What does "can't get the submit button to work" mean?
You need to be a bit more descriptive, including any exception messages.

On my computer, when I hit the button it doesn't do anything.

[Tolls]

What siva is saying is indexes for an array run from 0 to length - 1.

Consequently prices[4] will cause an array index out of bounds exception, since there are only 4 entries in that array. In addition (and they missed this bit) "index <= size" will cause the same problem.

You would see this if you looked at the console of whatever it is you are using to run this.

[ocarabal]

Man, I feel dumb, now I understand what you mean. The same thing got me when I was first learning about arrays. In the book I think it was called off by one or something like that.

[j2me64]

Man, I feel dumb, now I understand what you mean. The same thing got me when I was first learning about arrays. In the book I think it was called off by one or something like that.

the WheelListener will also cause an runtime error when you select the last listitem from the weel combobox, because prices[1][wheel.getSelectedIndex()] has only 3 elements but the combobox returns 4 when you select the last item. so i guess the right code should be

wheelPrice = prices[2][wheel.getSelectedIndex()];