Updating a JPanel from an array

Question

In this program, i have to create a GUI that saves objects of Contacts onto an array which then is turned into an array to be passed into the constructor of the default table model. I know i'm doing an extra step here.

The back up button actually saves whatever is in the Vector of contacts onto a binary file. The load button will load whatever file name you put in the username back into the vector. The view all contacts should display everything that is in the vector(well technically the contactListArray).

I'm having this problem where i can't get the JTable on the view card to update. If I load the contacts, and then click load contacts it shows, so i know the data is being written into the .dat file correctly. The problem seems to be that once i click on the view button the JTable is creating and won't change, even though i have it set to change in the method.

The problem, i think, is down at the where is says if(source == viewBut) that entire block i think may be the problem. Thank you for your help in advance, i really appreciate it.

/*
* Lab number: Final Project
* Robert Lopez
* Section number: 4
*/

import javax.swing.*;
import javax.swing.table.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.util.*;
import javax.swing.event.*;
import javax.swing.table.TableModel;


class Contact implements Serializable{ String firstName, lastName, eAddress, address, phoneNum; }

public class finalLab implements ActionListener{
    static CardLayout layout;

    static private JFrame frame = new JFrame("Address Book");

    static private JButton[] topMenuButton = new JButton[5];

    static private Vector<Contact> contactList = new Vector<Contact>();
    static private int contactSize = 0;

    static private String[] columnNames = {"First Name", "Last Name","E-Mail Address", "Address", "Phone Number"};

    static private String[][] contactListArray;

//START--------------------------Menu Card----------------------------------------------

        static JPanel menuCard = new JPanel(new BorderLayout());

    static JPanel menuTop = new JPanel( new GridLayout(2,1) );

    static private JLabel firstLabel = new JLabel("Use The Buttons Below To Manage Contacts");


    static JPanel menuMid = new JPanel(new FlowLayout());
    static private JLabel userName = new JLabel("User Name:");
    static private JTextField userNameField = new JTextField("", 15);
    static private JLabel numContacts = new JLabel("Number of Contacts:");
    static private JTextField numContactsField= new JTextField("", 15);


    static private JPanel menuLower = new JPanel(new GridLayout(2,8));
    static private JButton loadBut = new JButton("Load Contacts");
    static private JButton addBut = new JButton("Add New Contacts");
    static private JButton searchBut = new JButton("Search Contacts");
    static private JButton sortBut = new JButton("Sort Contacts");
    static private JButton deleteBut = new JButton("Delete Contacts");
    static private JButton viewBut = new JButton("View All Contacts");
    static private JButton backupBut = new JButton("Backup Contacts");
    static private JButton blankBut = new JButton("");

//END---------------------------------Menu Card------------------------------------




//START---------------------------------View Card------------------------------------

    //View Panel

    static private JPanel viewCard = new JPanel(new BorderLayout());
    static private JPanel viewCardLower = new JPanel();

    static private JLabel viewLabel = new JLabel("Contact List");

    static private JTable viewContacts;

    static private JPanel viewCardMid = new JPanel(new BorderLayout());
    static private JTableHeader header;
    static private JScrollPane scrollPane = new JScrollPane();


//END---------------------------------View Card------------------------------------




//START-----------------------------------Delete Card------------------------------------

         //Delete Panel
    static private JPanel deleteCard = new JPanel(new GridLayout (3,1));
    static private JPanel deleteMid = new JPanel();
    static private JPanel deleteLower = new JPanel();

    static private JLabel deleteLabel = new JLabel("Delete Contacts");
    static private JLabel contactInfoLabel = new JLabel("Contact Phone #");
    static private JTextField contactInfoField = new JTextField("", 15);

//END-----------------------------------Delete Card---------------------------------




//START-----------------------------------Add Contact-------------------------------

    static private JPanel addCard = new JPanel(new GridLayout(6,2));
    static private JLabel firstNameLabel = new JLabel("First Name");
    static private JLabel lastNameLabel = new JLabel("Last Name");
    static private JLabel eAddressLabel = new JLabel(" E-Mail Address");
    static private JLabel addressLabel = new JLabel("Address");
    static private JLabel phoneNumLabel = new JLabel("Phone No.");

    static private JTextField firstNameField = new JTextField("", 10);
    static private JTextField lastNameField = new JTextField("", 10);
    static private JTextField eAddressField = new JTextField("", 10);
    static private JTextField addressField = new JTextField("", 10);
    static private JTextField phoneNumField = new JTextField("", 10);

    static private JButton saveContactBut = new JButton("Save New Contact");

    static private JPanel addLowerLeft = new JPanel();
    static private JPanel addLowerRight = new JPanel();

//END------------------------------------Add Contact-----------------------------





//******************************   MAIN METHOD   *******************************




    static JPanel contentPane = (JPanel)frame.getContentPane();


    static private JPanel mainPanel = new JPanel();

    public static void main(String[] args){
        ActionListener AL = new finalLab();




        mainPanel.setLayout(layout = new CardLayout() );

        contentPane.setLayout(new BorderLayout());


        //Buttons, Labels
        loadBut.addActionListener(AL);
        for(int i = 0; i < 5; i++){
            topMenuButton[i] = new JButton("Top Menu");
            topMenuButton[i].addActionListener(AL);
        }
        backupBut.addActionListener(AL);
        viewBut.addActionListener(AL);
        addBut.addActionListener(AL);
        deleteBut.addActionListener(AL);
        saveContactBut.addActionListener(AL);

//-------------------------------------------------------

        //Top Menu

        firstLabel.setHorizontalAlignment(JTextField.CENTER);
        firstLabel.setFont(new Font( "serif", Font.BOLD, 25 ));
        menuTop.add(firstLabel);

        numContactsField.setEditable(false);
        numContactsField.setText("" + contactSize);

        //Adding Middle Content
        menuMid.add(userName);
        menuMid.add(userNameField);
        menuMid.add(numContacts);
        menuMid.add(numContactsField);


        //Adding Lower Content
        menuLower.add(loadBut);
        menuLower.add(addBut);
        menuLower.add(searchBut);
        menuLower.add(sortBut);
        menuLower.add(deleteBut);
        menuLower.add(viewBut);
        menuLower.add(backupBut);
        menuLower.add(blankBut);

        menuCard.add(menuTop, BorderLayout.NORTH);
        menuCard.add(menuMid, BorderLayout.CENTER);
        menuCard.add(menuLower, BorderLayout.SOUTH);

//-------------------------------------------------------

        //Delete Card
        deleteLabel.setHorizontalAlignment(JTextField.CENTER);
        deleteLabel.setFont(new Font( "serif", Font.BOLD, 25 ));
        deleteCard.add(deleteLabel);
        deleteMid.add(contactInfoLabel);
        deleteMid.add(contactInfoField);
        deleteCard.add(deleteMid);
        deleteLower.add(topMenuButton[0]);
        deleteCard.add(deleteLower);

//-------------------------------------------------------


        //Add Card
        firstNameLabel.setHorizontalAlignment(JTextField.RIGHT);
        lastNameLabel.setHorizontalAlignment(JTextField.RIGHT);
        eAddressLabel.setHorizontalAlignment(JTextField.RIGHT);
        addressLabel.setHorizontalAlignment(JTextField.RIGHT);
        phoneNumLabel.setHorizontalAlignment(JTextField.RIGHT);

        addCard.add(firstNameLabel);
        addCard.add(firstNameField);
        addCard.add(lastNameLabel);
        addCard.add(lastNameField);
        addCard.add(eAddressLabel);
        addCard.add(eAddressField);
        addCard.add(addressLabel);
        addCard.add(addressField);
        addCard.add(phoneNumLabel);
        addCard.add(phoneNumField);

        addLowerLeft.add(saveContactBut);
        addLowerRight.add(topMenuButton[1]);

        addCard.add(addLowerLeft);
        addCard.add(addLowerRight);

//----------------------------------------------------------

        //View Card

        viewLabel.setHorizontalAlignment(JTextField.CENTER);
        viewLabel.setFont(new Font( "serif", Font.BOLD, 25 ));
        viewCard.add(viewLabel, BorderLayout.NORTH);
        viewCardLower.add(topMenuButton[2]);
        viewCard.add(viewCardLower, BorderLayout.SOUTH);











        //Adding to frame

        mainPanel.add("Menu Card", menuCard);
        mainPanel.add("Delete Card", deleteCard);
        mainPanel.add("Add Card", addCard);
        //mainPanel.add("View Card", viewCard);

        contentPane.add(mainPanel); 
        layout.show(mainPanel, "Menu Card");

        frame.pack();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(700, 275);
        frame.setResizable(false);
        frame.setVisible(true);


    }


public void actionPerformed(ActionEvent e){
    Object source =e.getSource();


    if(source == loadBut){
        try {
            FileInputStream fis = new FileInputStream (userNameField.getText());
            ObjectInputStream ois = new ObjectInputStream(fis);
            contactList.clear();
            contactSize = 0;
            for(; true; contactSize++){
                 contactList.add( (Contact) ois.readObject() );

            numContactsField.setText("" + (contactSize+1) );

            }
        } catch(EOFException e2){
        } catch(Exception e2){ 
            e2.printStackTrace();
        } 



    }
    if(source == addBut)
        layout.show(mainPanel, "Add Card");

    if(source == viewBut){
        contactListArray = new String[contactSize][5];

        for(int i = 0; i < contactSize; i++){
            contactListArray[i][0] = contactList.get(i).firstName;
            contactListArray[i][1] = contactList.get(i).lastName;
            contactListArray[i][2] = contactList.get(i).eAddress;
            contactListArray[i][3] = contactList.get(i).address;
            contactListArray[i][4] = contactList.get(i).phoneNum;
        }



        DefaultTableModel model = new DefaultTableModel(contactListArray,columnNames);
        viewContacts = new JTable(model);

        header = viewContacts.getTableHeader();

        viewContacts.setFillsViewportHeight(true);

        viewContacts.revalidate();
        viewCardMid.add(header, BorderLayout.NORTH);
        viewCardMid.add(viewContacts, BorderLayout.CENTER);

        viewCard.add(viewCardMid, BorderLayout.CENTER);

        mainPanel.add("View Card", viewCard);

        layout.show(mainPanel, "View Card");
    }

    if(source == deleteBut)
        layout.show(mainPanel, "Delete Card");


    if(source == saveContactBut){
        contactList.add(new Contact());

        contactList.get(contactSize).firstName = firstNameField.getText();
        contactList.get(contactSize).lastName = lastNameField.getText();
        contactList.get(contactSize).eAddress = eAddressField.getText();
        contactList.get(contactSize).address = addressField.getText();
        contactList.get(contactSize).phoneNum = phoneNumField.getText();

        contactSize++;

        firstNameField.setText("");
        lastNameField.setText("");
        eAddressField.setText("");
        addressField.setText("");
        phoneNumField.setText("");
    }


    if(source == backupBut){
        try{
            FileOutputStream fos = new FileOutputStream (userNameField.getText(), false);
            ObjectOutputStream oos = new ObjectOutputStream(fos);

            for(int i = 0; i < contactSize; i++)
                oos.writeObject(contactList.get(i));
            oos.close();
        }
        catch (IOException e2){
            System.out.println("IO Exception " + e2);
        }
    }

    for(int i = 0; i < 5; i++)
        if(source == topMenuButton[i]){
            layout.show(mainPanel, "Menu Card");
            numContactsField.setText("" + contactSize);
        }
}
}   

Answer 1

The problem revolves around you lack of understanding in how tables and the CardLayout works..

// This is good...
DefaultTableModel model = new DefaultTableModel(contactListArray, columnNames);
// This is bad...
viewContacts = new JTable(model);

// This is bad...and raises some eyebrows
header = viewContacts.getTableHeader();

// This okay, but doesn't belong here, and is pointless given the following code...
viewContacts.setFillsViewportHeight(true);

// Pointless, you've not added the component to anything yet..
viewContacts.revalidate();
// ??  What ??
viewCardMid.add(header, BorderLayout.NORTH);
// Not good.  The table should be added to a JScrollPane first and the scroll
// pane added to the card
viewCardMid.add(viewContacts, BorderLayout.CENTER);

// Okay, but wrong place...
viewCard.add(viewCardMid, BorderLayout.CENTER);

// Here is your main problem.  The card layout only allows one component to exist
// for a given name.  If you try and add another card, it is discarded and the first
// component with that name remains
mainPanel.add("View Card", viewCard);

// Not bad...
layout.show(mainPanel, "View Card");

Instead of creating the table view when the view button is pressed, you should initalise and the view when you first create the UI and replace/update the table model when you click the view button...

In your constructor you should add...

viewContacts = new JTable(); // Don't need the model at this stage
viewContacts.setFillsViewportHeight(true);
viewCardMid.add(new JScrollPane(viewContacts), BorderLayout.CENTER);
mainPanel.add("View Card", viewCard);

And in your view button action code...

DefaultTableModel model = new DefaultTableModel(contactListArray, columnNames);
viewContacts.setModel(model);
mainPanel.add("View Card", viewCard);

Also, as has begin pointed about, you should not be using static class fields, it's not required in your case and will cause you issues as the complexity of your program grows.

You should be using if-else statements in you action performed method, this will reduce the possibility of logic errors and help improve performance

You should also investigate moving the logic for each view into it's own class, so as to reduce the clutter in your main class

Take the time to read through Creating a GUI With JFC/Swing, in particular, I'd looking into How to use Tables and How to use CardLayout

Answer 2

You make your variables static. The memory for static variables is not allocated on the stack but in regular memory. I didnt look at your code in detail but i would try to remove all static variables in your class and try again from there.