I have to create a CD inventory program for my first Java class. The book is poorly written and extremely verbose. I have created 4 frames to handle each requirement of the assignment. But the book doesn’t explain how to write arrays to a .dat file. If I could get an idea of how to add data to an array from my TextFields then write to a .dat file I could stumble through the rest. Here is what I have so far. How do I take my JTextFields from my Add CD listener and write to a .dat file so I can view it later.
import java.util.*;
import java.text.DecimalFormat;
import java.text.NumberFormat;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.lang.SecurityException;
import java.util.Formatter;
import java.util.FormatterClosedException;
import java.util.NoSuchElementException;
import java.util.Scanner;
import javax.swing.border.Border;
import javax.swing.border.LineBorder;
class CDinventoryItem extends JFrame implements Comparable <CDinventoryItem> {
private String sPtitle;
private String genreCD;
private int iPitemNumber;
private int iPnumberofUnits;
private double dPunitPrice;
private double dEvalue;
private JFrame frame2= new JFrame();
private JFrame frame3= new JFrame();
private JFrame frame4= new JFrame();
private JPanel panel1 = new JPanel();
private JPanel panel2 = new JPanel();
private JPanel panel3 = new JPanel();
private JPanel panel4 = new JPanel();
private JPanel panel5 = new JPanel();
private JPanel panel6 = new JPanel();
private JLabel[] label = new JLabel[20];
private JTextField titleField;
private JTextField itemNField;
private JTextField numofunitsField;
private JTextField priceField;
private JButton next;
private JButton prev;
private JButton addCD = new JButton ("Add CD");
private JButton save = new JButton ("Save");
private JButton delete;
private JButton modify;
private JButton search = new JButton ("Search for CD");
private JButton mainmenu;
private JButton displayCD = new JButton ("Display Inventory");
private CDinventoryItem [] inven;
private DataOutputStream outFile;
private DataInputStream inputFile;
public CDinventoryItem (String title, int itemNumber, int numberofUnits,
double unitPrice, String genre){
sPtitle = title;
iPitemNumber = itemNumber;
iPnumberofUnits = numberofUnits;
dPunitPrice = unitPrice;
genreCD = genre;
for(int i = 0; i < label.length; i++) {
label[i] = new JLabel();
}
setResizable(false);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
panel1.add(label[0]);
Icon bug = new ImageIcon( getClass().getResource( "mylogo.JPG" ) );
label[0].setIcon( bug );
label[0].setPreferredSize(new Dimension(400, 150));
panel1.add(label[1]);
label[1].setText("Press button to choose option:");
label[1].setPreferredSize(new Dimension(400, 50));
panel1.add(panel2);
panel2.setPreferredSize(new Dimension(400, 50));
ButtonListerner inputNewCD = new ButtonListerner();
panel2.add(addCD);
addCD.addActionListener(inputNewCD);
ButtonListerner searchCD = new ButtonListerner();
panel2.add(search);
search.addActionListener(searchCD);
ButtonListerner display = new ButtonListerner();
panel2.add(displayCD);
displayCD.addActionListener(display);
setContentPane(panel1);
}
private class ButtonListerner implements ActionListener
{
public void actionPerformed ( ActionEvent event) {
if (event.getActionCommand().equals("Add CD"))
{
frame2.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
frame2.setLocation(525,100);
frame2.setSize(425, 425);
frame2.setVisible( true );
frame2.add(panel3);
panel3.add(label[0]);
panel3.add(label[2]);
label[2].setText("Enter title of CD:");
label[2].setPreferredSize(new Dimension(100, 25));
JTextField titleText = new JTextField(20);
panel3.add (titleText);
sPtitle.equals(titleText);
label[2].setPreferredSize(new Dimension(175, 25));
panel3.add(label[3]);
label[3].setText("Enter number of CDs:");
JTextField numCDText = new JTextField(5);
panel3.add(numCDText);
label[3].setPreferredSize(new Dimension(275, 25));
panel3.add(label[4]);
label[4].setText("Enter price of CD:");
JTextField priceCDText = new JTextField(6);
panel3.add(priceCDText);
label[4].setPreferredSize(new Dimension(274, 25));
panel3.add(label[5]);
label[5].setText("Pick genre:");
String stringBox[] = {"Drama","Action","Comedy"};
JComboBox comboBox = new JComboBox(stringBox);
comboBox.setEditable(false);
panel3.add(comboBox);
panel3.add(save);
}
if (event.getActionCommand().equals("Search for CD")){
frame3.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
frame3.setLocation(100,525);
frame3.setSize(425, 425);
frame3.setVisible( true );
frame3.add(panel4);
panel4.add(label[0]);
panel4.add(label[6]);
label[6].setText("Enter name of CD you want to search for:");
JTextField searchName = new JTextField(20);
panel4.add(searchName);
panel4.add(label[7]);
label[7].setText("Or search by genre:");
JCheckBox checkB1 = new JCheckBox("Drama");
JCheckBox checkB2 = new JCheckBox("Action");
JCheckBox checkB3 = new JCheckBox("Comedy");
panel4.add(checkB1);
panel4.add(checkB2);
panel4.add(checkB3);
}
if (event.getActionCommand().equals("Display Inventory")){
frame4.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
frame4.setLocation(525,525);
frame4.setSize(425, 425);
frame4.setVisible( true );
frame4.add(panel5);
panel5.add(label[0]);
panel5.add(label[8]);
label[8].setText("List of CDs:");
}
if (event.getActionCommand().equals("Save")){
String dataFile = "inventory.dat";
try{
outFile = new DataOutputStream(new BufferedOutputStream(
new FileOutputStream(dataFile)));
}
catch(FileNotFoundException fileNotFoundException ){
}
}
}}
public int compareTo(CDinventoryItem otherItem) {
return this.sPtitle.compareTo(otherItem.getTitle());
}
@Override
public String getTitle() {
return sPtitle;
}
}
public class CDinventoryprogram {
public static void main(String[] args) {
JOptionPane.showMessageDialog( null, "Welcome to my CD inventory program!!"
, "Inventory", JOptionPane.INFORMATION_MESSAGE);
CDinventoryItem initem = new CDinventoryItem ("", 0, 0, 0.0,"" );
initem.setDefaultCloseOperation( JFrame.DISPOSE_ON_CLOSE );
initem.setLocation(100,100);
initem.setSize(425, 425);
initem.setVisible( true );
}
In the method ButtonListerner.actionPerformed(), when the Add CD button is pressed (checked by event.getActionCommand().equals(“Add CD”)), you are creating a local text field:
The first thing you need to do is use the one in the outer class (so you can get the values later):
After this, when Save button is clicked, now your fields will hold the user input, so you can now get those values:
Now to write to a file, you need to use an OutputStream. There are many OutputStream subclasses, each one has it’s own use. BufferedWriter is for writing text, DataOutputStream is for writing binary data, you should not use both together like you are doing now. Assuming you want to write binary data, you can do this:
Note: To keep things simple, I didn’t added proper error handling (the outFile.close() should be in a finally statement).