Prevent Duplicate value from jlist to jlist by way of a jbutton

Here is what I have so far. Now I just get the "No duplicates please!" message whenever I add anything to lbSelection.

I need to recognize that there is a duplicate and prevent the value from being entered into the list!

Any help you can provide would be greatly appreciated! Thanks!

HERE is the whole program

* Listbox (JList, actually) demo
package ListBoxManiaPackage;

import java.awt.BorderLayout;

public class ListBoxMania extends JFrame {

private JPanel contentPane;
	private final JList lbChoices = new JList();
	
	// *** Initialize the Selections list box to use a Model that supports adding and removing ***
	private final JList lbSelection = new JList(new DefaultListModel());
	
	private final JButton btnAddToSelected = new JButton(">");
	private final JButton btnRemoveFromSelected = new JButton("<");
	private final JButton btnAddAll = new JButton(">>");
	private final JButton btnRemoveAll = new JButton("<<");
	private final JButton btnReport = new JButton("Report");
	private final JLabel lblSelectedCount = new JLabel("Count of Selected:");
	private final JTextField UserEntryBox = new JTextField();
	private final JLabel lblNamesSelected = new JLabel("Teams Selected:");
	private final JLabel jl = new JLabel();
	private final JLabel lblIcon = new JLabel("");
	ImageIcon image = new ImageIcon("resources/nfl.png");
	private final JSpinner sTotalPoints = new JSpinner();
	private final JRadioButton rdbtnTeam1 = new JRadioButton("Team 1");
	private final JRadioButton rdbtnTeam2 = new JRadioButton("Team 2");
	private final JLabel lblTotalPoints = new JLabel("Total Points");
	private final JLabel lblChooseWinner = new JLabel("Choose Winner");
	private final JButton btnSubmit = new JButton("Submit");
	private final JLabel lblSelectTwoTeams = new JLabel("Select Two Teams!");
	private final JFrame j = new JFrame("");
	private final JButton btnExit = new JButton("Quit");

/**
	 * Launch the application.
	 */
	public static void main(String[] args) {
		EventQueue.invokeLater(new Runnable() {
			public void run() {
				try {
					ListBoxMania frame = new ListBoxMania();
					frame.setVisible(true);
				} catch (Exception e) {
					e.printStackTrace();
				}
			}
		});
	}

/**
	 * Create the frame.
	 */
	public ListBoxMania() {
		setTitle("AFC Team Challenge");
					
		UserEntryBox.setBounds(31, 13, 136, 20);
		UserEntryBox.setColumns(10);
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		setBounds(100, 100, 471, 467);
		contentPane = new JPanel();
		contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
		contentPane.setBackground(Color.red);
		setContentPane(contentPane);
		contentPane.setLayout(null);
		
		lbChoices.setModel(new DefaultListModel() {
			String[] values = new String[] {"Bengals", "Steelers", "Browns", "Ravens"};
			public int getSize() {
				
				return values.length;
			
			}
			
			public Object getElementAt(int index) {
			
				return values[index];
			
			}
		
		});

lbChoices.setBounds(31, 44, 136, 133);
		lbChoices.setBackground(Color.blue);		
		lbChoices.setForeground(Color.white);			
		contentPane.add(lbChoices);
	
		lbSelection.setBounds(284, 44, 136, 133);
		lbSelection.setBackground(Color.blue);		
		lbSelection.setForeground(Color.white);			
		contentPane.add(lbSelection);
	
		btnAddToSelected.addMouseListener(new MouseAdapter() {
			@Override
			public void mouseClicked(MouseEvent e) {
			
				// Append an item from the choices ListBox to the selected ListBox.
				// This does not check for an item that has already been selected: it will be added again.
				DefaultListModel model = (DefaultListModel) lbSelection.getModel();
				
				int pos = lbSelection.getModel().getSize();
			
				model.addElement(lbChoices.getSelectedValue().toString());			
					
				if (model.contains(lbSelection.getSelectedIndices()));
				
				JOptionPane.showMessageDialog(btnReport, "No duplicates please!");
//		
			}
		});
	
		btnAddToSelected.setBounds(179, 80, 95, 25);
		
		contentPane.add(btnAddToSelected);
	
		btnRemoveFromSelected.addActionListener(new ActionListener() {
		
			public void actionPerformed(ActionEvent e) {
			
			}
	
		});
		btnRemoveFromSelected.addMouseListener(new MouseAdapter() {
			@Override
			public void mouseClicked(MouseEvent e) {
				
				DefaultListModel model = (DefaultListModel) lbSelection.getModel();
		
				model.removeElementAt(lbSelection.getSelectedIndex());
			
			}
	
		});
		
		btnRemoveFromSelected.setBounds(179, 116, 95, 25);
		
		contentPane.add(btnRemoveFromSelected);
		btnAddAll.addMouseListener(new MouseAdapter() {
			@Override
			public void mouseClicked(MouseEvent e) {
				// Add all items to the selection list box
					
				DefaultListModel choicesModel  = (DefaultListModel) lbChoices.getModel();
				
				DefaultListModel selectionModel  = (DefaultListModel) lbSelection.getModel();
				
				int max = choicesModel.getSize();
			
				for (int i = 0; i < max; i++) {
		
					selectionModel.addElement(choicesModel.getElementAt(i));	
									
//				JOptionPane.showMessageDialog(btnReport, "No duplicates please!");
					
				}	
			}
		});
	
		btnAddAll.setBounds(179, 44, 95, 25);
		
		contentPane.add(btnAddAll);
		
		btnRemoveAll.addMouseListener(new MouseAdapter() {
			@Override
			public void mouseClicked(MouseEvent e) {
		
				ClearSelection();
			}
		});
	
		btnRemoveAll.setBounds(179, 152, 95, 25);
		
		contentPane.add(btnRemoveAll);
		
		btnReport.addActionListener(new ActionListener() {
		
			public void actionPerformed(ActionEvent arg0) {
				
				int selected[] = lbSelection.getSelectedIndices();
				
				if (selected.length <= 0){
					
					JOptionPane.showMessageDialog(btnReport, "Must select at least one team to report!");
					
				}
				
				for (int i = 0; i < selected.length; i++) {
				
					Object item = lbSelection.getModel();
				
					lblNamesSelected.setText("The Teams Selected are: " + item);
					
				}
				
				int size = lbSelection.getModel().getSize();
				
				for (int i = 0; i < size; i++){

lblSelectedCount.setText("The Count of Teams is " + lbSelection.getModel().getSize());
				
				}
			}
		});
		btnReport.setBounds(179, 186, 95, 23);
		
		contentPane.add(btnReport);
		lblSelectedCount.setBounds(118, 222, 215, 14);
		lblSelectedCount.setForeground(Color.white);		
		contentPane.add(lblSelectedCount);
		
		contentPane.add(UserEntryBox);
		lblNamesSelected.setBounds(10, 237, 410, 14);
		
		contentPane.add(lblNamesSelected);
		contentPane.add(jl);
		lblNamesSelected.setForeground(Color.white);		
		lblIcon.setBounds(40, 288, 186, 141);
		
		
		lblIcon.setIcon(image);
		contentPane.add(lblIcon);
		sTotalPoints.setModel(new SpinnerNumberModel(2, 2, 200, 1));
		sTotalPoints.setForeground(Color.white);
		sTotalPoints.setBounds(389, 324, 47, 20);
		
		contentPane.add(sTotalPoints);
		sTotalPoints.setBackground(Color.red);
		sTotalPoints.setForeground(Color.white);
		rdbtnTeam1.setBounds(327, 253, 109, 23);
		rdbtnTeam1.setForeground(Color.white);		
		rdbtnTeam1.setBackground(Color.red);		
		rdbtnTeam2.setForeground(Color.white);		
		rdbtnTeam2.setBackground(Color.red);		
		
		
		contentPane.add(rdbtnTeam1);
		rdbtnTeam2.setBounds(327, 288, 109, 23);
		rdbtnTeam2.setForeground(Color.white);		
		rdbtnTeam2.setBackground(Color.red);		
		
		contentPane.add(rdbtnTeam2);
		lblTotalPoints.setBounds(302, 326, 79, 14);
		lblTotalPoints.setForeground(Color.white);
		
		contentPane.add(lblTotalPoints);
		lblChooseWinner.setBounds(211, 276, 117, 14);
		
		contentPane.add(lblChooseWinner);
		lblChooseWinner.setForeground(Color.white);		
		lblChooseWinner.setBackground(Color.red);		
		btnSubmit.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent arg0) {
				
				JOptionPane.showMessageDialog(btnReport, "Thank you!  Your Picks Have Been Submitted!");				
			}
		});
		
		btnSubmit.setBounds(238, 391, 95, 25);
		
		contentPane.add(btnSubmit);
		lblSelectTwoTeams.setForeground(Color.WHITE);
		lblSelectTwoTeams.setFont(new Font("Rockwell Extra Bold", Font.PLAIN, 20));
		lblSelectTwoTeams.setBounds(199, 17, 244, 14);
		
		contentPane.add(lblSelectTwoTeams);
		btnExit.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				
				System.exit(0);
			}
		});
		btnExit.setBounds(348, 391, 95, 25);
		
		contentPane.add(btnExit);

}
	/**
	 * Clear all the selected items by erasing the lbSelected listBox
	 */
	private void ClearSelection() {
		DefaultListModel selectionModel  = (DefaultListModel) lbSelection.getModel();
		selectionModel.clear();
	}
}

do you really need to retain all the teams on the left?

Most similar-concept programs I've seen move the selection from the left to the right (or back),
meaning no possibility of duplicates.

Michael Dunn wrote:do you really need to retain all the teams on the left?

Most similar-concept programs I've seen move the selection from the left to the right (or back),
meaning no possibility of duplicates.

I guess I don't need them but the text box above lbChoices is for a user to enter another team so I think I would need to keep them in the left side list.

> Here is what I have so far. Now I just get the "No duplicates please!" message whenever I add anything to lbSelection.

OK, this bit looks easily fixable

now it shouldn't 'always' show.

do you still need help on duplicates? or was this all you were after?

Michael Dunn wrote:> Here is what I have so far. Now I just get the "No duplicates please!" message whenever I add anything to lbSelection.

OK, this bit looks easily fixable

if (model.contains(lbSelection.getSelectedIndices()));//<---remove the ; JOptionPane.showMessageDialog(btnReport, "No duplicates please!");

now it shouldn't 'always' show.

do you still need help on duplicates? or was this all you were after?

I was hoping that line would prevent my duplicates but it didn't! So yes, still need help preventing duplicates!

this is just for the add single button
(comment out your old method, in case you need it later)

replace with this

Michael Dunn wrote:this is just for the add single button
(comment out your old method, in case you need it later)

replace with this

btnAddToSelected.addMouseListener(new MouseAdapter() { //public void mouseClicked(MouseEvent e) {//poor choice - mouseClicked doesn't always fire @Override public void mousePressed(MouseEvent e) { DefaultListModel model = (DefaultListModel) lbSelection.getModel(); if (model.contains(lbChoices.getSelectedValue())) { JOptionPane.showMessageDialog(btnReport, "No duplicates please!"); } else model.addElement(lbChoices.getSelectedValue()); } });

Thanks so much! I couldn't stare at it any longer. This also helped me get the add all button working as well! Now if I can just figure out how to add text to the jlist from the jtextfield on a focuslost!

> Now if I can just figure out how to add text to the jlist from the jtextfield on a focuslost!

really a bad idea (many reasons why accidental loss of focus),
better to add a little 'add' button beside the textfield

Michael Dunn wrote:> Now if I can just figure out how to add text to the jlist from the jtextfield on a focuslost!

really a bad idea (many reasons why accidental loss of focus),
better to add a little 'add' button beside the textfield

100% agree with you! Thanks again for your help.