Adding array list to JList - MVC - Getting nothing but memory addresses!

[Anthony Gilke]

I have an array list in a separate class called "Bottle" and a "View" class with a method called InitView. I have a contentpane that displays a JList and it populates the bottles memory addresses, but i need it to to populate the string version so it's readable...

Any help would be greatly appreciated.



VIEW CLASS

package viewPackage;

import java.awt.BorderLayout;

public class View extends JFrame {

	static private JPanel contentPane;
	static ArrayList<Bottle> myBottles = new ArrayList<Bottle>();
	private final JButton btnQuit = new JButton("Quit");
	private final static JList list = new JList();
	private static final String String = null;
	private final JLabel lblVendingMachineOptions = new JLabel("Vending Machine Options");
	
	/**
	 * Launch the application.
	 */
	public static void main(String[] args) {
		EventQueue.invokeLater(new Runnable() {
			public void run() {
				try {
					InitSystem();
					View frame = new View();
					InitView(contentPane);
					frame.setVisible(true);
				} catch (Exception e) {
					e.printStackTrace();
				}
			}
		});
	}

	/**
	 * Create the frame.
	 */
	public View() {
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		setBounds(100, 100, 450, 300);
		contentPane = new JPanel();
		contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
		setContentPane(contentPane);
		contentPane.setLayout(null);
		btnQuit.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent arg0) {
				System.exit(0);
			}
		});
		btnQuit.setBounds(335, 228, 89, 23);

		contentPane.add(btnQuit);
		list.setFont(new Font("Tahoma", Font.PLAIN, 15));
		list.setBounds(28, 37, 221, 175);

		contentPane.add(list);
		lblVendingMachineOptions.setBounds(28, 22, 162, 14);
		
		contentPane.add(lblVendingMachineOptions);
	}

	private static void InitSystem() throws Exception{
		Model myModel = new Model();
		if (myModel.ConnectToDatabase()) {
			// Create an empty list of bottles
			myModel.ReadBottles(myBottles);

		} else {
			throw new Exception("View.InitSystem(): Unable to connect to database");
		}
	}
	private static void InitView(JPanel contentPane) {			
		
		DefaultListModel<String> model = new DefaultListModel<String>();

		for(Bottle i:myBottles) {

			model.addElement(i.toString());
			
		}

		list.setModel(model);
		list.setSelectedIndex(0);


	}
}

BOTTLE CLASS

package bottlePackage;

import config.Config;
import productPackage.Product;


public class Bottle extends Product{
	private double price;
	/**
	 * Constructor
	 * @param SKU The SKU of the product
	 * @param price The cost of the product
	 */
	public Bottle(String SKU, double price) throws Exception {
		super(SKU);
		setPrice(price);
		// TODO Auto-generated constructor stub
	}
	/**
	 * @param price The price of the SKU
	 * @return the price of the SKU
	 * @throws Exception if price is below Config.minimumPrice
	 */
	public double setPrice(double price) throws Exception {
		if (price >= Config.minimumPrice) {
			this.price = price; 
		} else {
			throw new Exception ("Bottle.setPrice(): price below minimum");
		}
		return price;
	}
	/**
	 * Get the price of the SKU
	 * @return The price of the SKU
	 */
	public double getPrice(){return price;}
	

}

[Darryl Burke]

By default, JList uses the toString() method of the objects populating it to obtain a String for display. You have two options: override Object's toString() in your Bottle class, or use a custom ListCellRenderer, probably extending DefaultListCellRenderer, that assembles the String you would like to display and sets it as the text of the renderer. For the latter approach, go through the Oracle tutorial on How to Use Lists which is linked from the API for JList.

edit On a closer look at your code, you're adding the values returned by toString() to a DefaultListModel<String>. You might want to consider using a DefaultListModel<Bottle> instead, as that can give you direct access to the selected Bottle via getSelectedItem().

[Anthony Gilke]

Darryl Burke wrote:By default, JList uses the toString() method of the objects populating it to obtain a String for display. You have two options: override Object's toString() in your Bottle class, or use a custom ListCellRenderer, probably extending DefaultListCellRenderer, that assembles the String you would like to display and sets it as the text of the renderer. For the latter approach, go through the Oracle tutorial on How to Use Lists which is linked from the API for JList.

edit On a closer look at your code, you're adding the values returned by toString() to a DefaultListModel<String>. You might want to consider using a DefaultListModel<Bottle> instead, as that can give you direct access to the selected Bottle via getSelectedItem().

I've added this but still get the memory addresses!

private static void InitView(JPanel contentPane) {
		// To Do: Display the list of bottles on the form. Somehow.
			
		
		DefaultListModel<Bottle> model = new DefaultListModel<Bottle>();

		for(Bottle i:myBottles) {

			model.addElement(i);
			
		}

		list.setModel(model);
		list.setSelectedIndex(0);


	}

[Darryl Burke]

1. Those aren't the memory addresses.
2. I've already told you what JList uses as the display value.

[Anthony Gilke]

Darryl Burke wrote:1. Those aren't the memory addresses.
2. I've already told you what JList uses as the display value.

Sorry I'm not sure of the proper term but it's not in a readable format. Just gives me bottlePackage.Bottle@15663a2 instead of the actual bottle data.

I think you told me to use getSelectedItem() but with the listModel I can't seem to pull that up.

I'll keep trying but appreciate any assistance. Thanks.