Inventory GUI Assignment

Question

I can't figure out how to get this to work correctly. I need the GUI to display one product at a time and add buttons "next, previous, last, first". My main problem is not being able to step through displaying the arrat one product at a time. That of course prevents me from applying any button actions. Any help for this Java moron would be greatly appreciated.
import java.util.*;
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class Inventory7 // Main class
     //main method begins execution of java application
     public static void main(String args[])
          int i; // varialbe for looping
          double total = 0; // variable for total inventory
          final int dispProd = 0; // variable for actionEvents
          // Instantiate a product object
          final ProductAdd[] nwProduct = new ProductAdd[5];
          // Instantiate objects for the array
          for (i=0; i<5; i++)
               nwProduct[0] = new ProductAdd("Paper", 101, 10, 1.00, "Box");
               nwProduct[1] = new ProductAdd("Pen", 102, 10, 0.75, "Pack");
               nwProduct[2] = new ProductAdd("Pencil", 103, 10, 0.50, "Pack");
               nwProduct[3] = new ProductAdd("Staples", 104, 10, 1.00, "Box");
               nwProduct[4] = new ProductAdd("Clip Board", 105, 10, 3.00, "Two Pack");
          for (i=0; i<5; i++)
               total += nwProduct.calcValue(); // calculate total inventory cost
          final JButton firstBtn = new JButton("First"); // first button
          final JButton prevBtn = new JButton("Previous"); // previous button
          final JButton nextBtn = new JButton("Next"); // next button
          final JButton lastBtn = new JButton("Last"); // last button
          final JLabel label; // logo
          final JTextArea textArea; // text area for product list
          final JPanel buttonJPanel; // panel to hold buttons
          //JLabel constructor for logo
          Icon logo = new ImageIcon("C:/logo.jpg"); // load logo
          label = new JLabel(logo); // create logo label
          label.setToolTipText("Company Logo"); // create tooltip
          buttonJPanel = new JPanel(); // set up panel
          buttonJPanel.setLayout( new GridLayout(1, 4)); //set layout
          // add buttons to buttonPanel
          buttonJPanel.add(firstBtn);
          buttonJPanel.add(prevBtn);
          buttonJPanel.add(nextBtn);
          buttonJPanel.add(lastBtn);
          textArea = new JTextArea(nwProduct[3]+"\n"); // create textArea for product display
          // add total inventory value to GUI
          textArea.append("\nTotal value of Inventory "+new java.text.DecimalFormat("$0.00").format(total)+"\n\n");
          textArea.setEditable(false); // make text uneditable in main display
          JFrame invFrame = new JFrame(); // create JFrame container
          invFrame.setLayout(new BorderLayout()); // set layout
          invFrame.getContentPane().add(new JScrollPane(textArea), BorderLayout.CENTER); // add textArea to JFrame
          invFrame.getContentPane().add(buttonJPanel, BorderLayout.SOUTH); // add buttons to JFrame
          invFrame.getContentPane().add(label, BorderLayout.NORTH); // add logo to JFrame
          invFrame.setTitle("Office Min Inventory"); // set JFrame title
          invFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); // termination command
          //invFrame.pack();
          invFrame.setSize(400, 400); // set size of JPanel
          invFrame.setLocationRelativeTo(null); // set screem location
          invFrame.setVisible(true); // display window
          // assign actionListener and actionEvent for each button
          firstBtn.addActionListener(new ActionListener()
               public void actionPerformed(ActionEvent ae)
                    textArea.setText(nwProduct[0]+"\n");
               } // end firstBtn actionEvent
          }); // end firstBtn actionListener
          lastBtn.addActionListener(new ActionListener()
               public void actionPerformed(ActionEvent ae)
                    textArea.setText(nwProduct[4]+"n");
               } // end lastBtn actionEvent
          }); // end lastBtn actionListener
//          prevBtn.addActionListener(new ActionListener()
//               public void actionPerformed(ActionEvent ae)
//                    dispProd = (nwProduct.length+dispProd-1) % nwProduct.length;
//                    textArea.setText(nwProduct.display(dispProd)+"\n");
//               } // end prevBtn actionEvent
//          }); // end prevBtn actionListener
     } // end main
} // end class Inventory6
class Product
     protected String prodName; // name of product
     protected int itmNumber; // item number
     protected int units; // number of units
     protected double price; // price of each unit
     protected double value; // value of total units
     public Product(String name, int number, int unit, double each) // Constructor for class Product
          prodName = name;
          itmNumber = number;
          units = unit;
          price = each;
     } // end constructor
     public void setProdName(String name) // method to set product name
          prodName = name;
     public String getProdName() // method to get product name
          return prodName;
     public void setItmNumber(int number) // method to set item number
          itmNumber = number;
     public int getItmNumber() // method to get item number
          return itmNumber;
     public void setUnits(int unit) // method to set number of units
          units = unit;
     public int getUnits() // method to get number of units
          return units;
     public void setPrice(double each) // method to set price
          price = each;
     public double getPrice() // method to get price
          return price;
     public double calcValue() // method to set value
          return units * price;
} // end class Product
class ProductAdd extends Product
     private String feature; // variable for added feature
     public ProductAdd(String name, int number, int unit, double each, String addFeat)
          // call to superclass Product constructor
          super(name, number, unit, each);
          feature = addFeat;
     }// end constructor
          public void setFeature(String addFeat) // method to set added feature
               feature = addFeat;
          public String getFeature() // method to get added feature
               return feature;
          public double calcValueRstk() // method to set value and add restock fee
               return units * price * 0.05;
          public String toString()
               return String.format("Product: %s\nItem Number: %d\nIn Stock: %d\nPrice: $%.2f\nType: %s\nTotal Value of Stock: $%.2f\nRestock Cost: $%.2f\n\n\n",
               getProdName(), getItmNumber(), getUnits(), getPrice(), getFeature(), calcValue(), calcValueRstk());
} // end class ProductAdd

Answer 1

I just have one more question. I have intergrated the code example you gave me into my original code. Now I have a ton of errors that seem to pertain to the fact that I have numbers involved. Please help.
import java.util.*;
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class Inventory extends JFrame// Main class
     private JLabel prodNameLabel;
     private JLabel numberLabel;
     private JLabel unitLabel;
     private JLabel priceLabel;
     private JLabel featureLabel;
     private JLabel valueLabel;
     private JLabel rstkLabel;
     private JLabel totalLabel;
     private JTextField prodNameField;
     private JTextField numberField;
     private JTextField unitField;
     private JTextField priceField;
     private JTextField featureField;
     private JTextField valueField;
     private JTextField rstkField;
     private JTextField totalField;
     private JButton firstBtn;
     private JButton prevBtn;
     private JButton nextBtn;
     private JButton lastBtn;
     private JPanel buttonJPanel;
     private JPanel fieldJPanel;
     private JPanel fontJPanel;
     private List<ProductAdd> nwProduct;
     private int currProd = 0;
     private double total; // variable for total inventory
     public Inventory()
          initComponents();
     private void initComponents()
          prodNameLabel = new JLabel("Product Name:");
          numberLabel = new JLabel("Item Number:");
          unitLabel = new JLabel("In Stock:");
          priceLabel = new JLabel("Each Item Cost:");
          featureLabel = new JLabel("Type of Item:");
          valueLabel = new JLabel("Value of Item Inventory:");
          rstkLabel = new JLabel("Cost to Re-Stock Item:");
          totalLabel = new JLabel("Total Value of Inventory:");
          firstBtn = new JButton("First");
          prevBtn = new JButton("Previous");
          nextBtn = new JButton("Next");
          lastBtn = new JButton("Last");
          prodNameField = new JTextField();
          prodNameField.setEditable(false);
          numberField = new JTextField();
          numberField.setEditable(false);
          unitField = new JTextField();
          unitField.setEditable(false);
          priceField = new JTextField();
          priceField.setEditable(false);
          featureField = new JTextField();
          featureField.setEditable(false);
          valueField = new JTextField();
          valueField.setEditable(false);
          rstkField = new JTextField();
          rstkField.setEditable(false);
          totalField = new JTextField();
          totalField.setEditable(false);
          prodNameLabel.setSize(200, 20);
          numberLabel.setSize(200, 20);
          unitLabel.setSize(200, 20);
          priceLabel.setSize(200, 20);
          featureLabel.setSize(200, 20);
          valueLabel.setSize(200, 20);
          rstkLabel.setSize(200, 20);
          totalLabel.setSize(200, 20);
          prodNameField.setSize(100, 20);
          numberField.setSize(100, 20);
          unitField.setSize(100, 20);
          priceField.setSize(100, 20);
          featureField.setSize(100, 20);
          valueField.setSize(100, 20);
          rstkField.setSize(100, 20);
          totalField.setSize(100, 20);
          buttonJPanel = new JPanel(); // set up panel
          buttonJPanel.setLayout( new GridLayout(1, 4)); //set layout
          // add buttons to buttonJPanel
          buttonJPanel.add(firstBtn);
          buttonJPanel.add(prevBtn);
          buttonJPanel.add(nextBtn);
          buttonJPanel.add(lastBtn);
          nwProduct = new ArrayList<ProductAdd>();
          nwProduct.add(new ProductAdd("Paper", 101, 10, 1.00, "Box"));
          nwProduct.add(new ProductAdd("Pen", 102, 10, 0.75, "Pack"));
          nwProduct.add(new ProductAdd("Pencil", 103, 10, 0.50, "Pack"));
          nwProduct.add(new ProductAdd("Staples", 104, 10, 1.00, "Box"));
          nwProduct.add(new ProductAdd("Clip Board", 105, 10, 3.00, "Two Pack"));
          total = (nwProduct.size() += calcValue());
          prodNameField.setText(nwProduct.get(currProd).getProdName());
          numberField.setInt(nwProduct.get(currProd).getItmNumber());
          unitField.setInt(nwProduct.get(currProd).getUnits());
          priceField.setInt(nwProduct.get(currProd).getPrice());
          featureField.setText(nwProduct.get(currProd).getFeature());
          valueField.setInt(nwProduct.get(currProd).calcValue());
          rstkField.setInt(nwProduct.get(currProd).calcValueRstk());
          totalField.setInt(total);
          fieldJPanel = new JPanel();
          fieldJPanel.setLayout(new GridLayout(8, 2));
          fieldJPanel.add(prodNameLabel);
          fieldJPanel.add(prodNameField);
          fieldJPanel.add(numberLabel);
          fieldJPanel.add(numberField);
          fieldJPanel.add(unitLabel);
          fieldJPanel.add(unitField);
          fieldJPanel.add(priceLabel);
          fieldJPanel.add(priceField);
          fieldJPanel.add(featureLabel);
          fieldJPanel.add(featureField);
          fieldJPanel.add(valueLabel);
          fieldJPanel.add(valueField);
          fieldJPanel.add(rstkLabel);
          fieldJPanel.add(rstkField);
          fieldJPanel.add(totalLabel);
          fieldJPanel.add(totalField);
          JFrame invFrame = new JFrame();
          invFrame.setLayout( new BorderLayout());
          invFrame.setTitle("Office Min Inventory");
          invFrame.getContentPane().add(fontJPanel, BorderLayout.NORTH);
          invFrame.getContentPane().add(buttonJPanel, BorderLayout.SOUTH);
          invFrame.getContentPane().add(fieldJPanel, BorderLayout.CENTER);
          invFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); // termination command
          invFrame.setSize(400, 400); // set size of JPanel
          invFrame.setLocationRelativeTo(null); // set screem location
          invFrame.setVisible(true); // display window
          firstBtn.addActionListener(new ActionListener()
               public void actionPerformed(ActionEvent evt)
                    goFirst();
          lastBtn.addActionListener(new ActionListener()
               public void actionPerformed(ActionEvent evt)
                    goLast();
          prevBtn.addActionListener(new ActionListener()
               public void actionPerformed(ActionEvent evt)
                    goBack();
          nextBtn.addActionListener(new ActionListener()
               public void actionPerformed(ActionEvent evt)
                    goNext();
     private void goFirst()
          prodNameField.setText(nwProduct.get(0).getProdName());
          numberField.setInt(nwProduct.get(0).getItmNumber());
          unitField.setInt(nwProduct.get(0).getUnits());
          priceField.setInt(nwProduct.get(0).getPrice());
          featureField.setText(nwProduct.get(0).getFeature());
          valueField.setInt(nwProduct.get(0).calcValue());
          rstkField.setInt(nwProduct.get(0).calcValueRstk());
          totalField.setInt(total);
     private void goLast()
          prodNameField.setText(nwProduct.get(nwProduct.size() - 1).getProdName());
          numberField.setInt(nwProduct.get(nwProduct.size() - 1).getItmNumber());
          unitField.setInt(nwProduct.get(nwProduct.size() - 1).getUnits());
          priceField.setInt(nwProduct.get(nwProduct.size() - 1).getPrice());
          featureField.setText(nwProduct.get(nwProduct.size() - 1).getFeature());
          valueField.setInt(nwProduct.get(nwProduct.size() - 1).calcValue());
          rstkField.setInt(nwProduct.get(nwProduct.size() - 1).calcValueRstk());
          totalField.setInt(total);
     private void goBack()
          if(currProd > 0)
               currProd--;
               prodNameField.setText(nwProduct.get(currProd).getProdName());
               numberField.setInt(nwProduct.get(currProd).getItmNumber());
               unitField.setInt(nwProduct.get(currProd).getUnits());
               priceField.setInt(nwProduct.get(currProd).getPrice());
               featureField.setText(nwProduct.get(currProd).getFeature());
               valueField.setInt(nwProduct.get(currProd).calcValue());
               rstkField.setInt(nwProduct.get(currProd).calcValueRstk());
               totalField.setInt(total);
     private void goNext()
          if(currProd < nwProduct.size() - 1)
               currProd++;
               prodNameField.setText(nwProduct.get(currProd).getProdName());
               numberField.setInt(nwProduct.get(currProd).getItmNumber());
               unitField.setInt(nwProduct.get(currProd).getUnits());
               priceField.setInt(nwProduct.get(currProd).getPrice());
               featureField.setText(nwProduct.get(currProd).getFeature());
               valueField.setInt(nwProduct.get(currProd).calcValue());
               rstkField.setInt(nwProduct.get(currProd).calcValueRstk());
               totalField.setInt(total);
     //main method begins execution of java application
          public static void main(String args[])
               new Inventory().setVisible(true);
          } // end main method
} // end class Inventory
class Product
     protected String prodName; // name of product
     protected int itmNumber; // item number
     protected int units; // number of units
     protected double price; // price of each unit
     protected double value; // value of total units
     public Product(String name, int number, int unit, double each) // Constructor for class Product
          prodName = name;
          itmNumber = number;
          units = unit;
          price = each;
     } // end constructor
     public void setProdName(String name) // method to set product name
          prodName = name;
     public String getProdName() // method to get product name
          return prodName;
     public void setItmNumber(int number) // method to set item number
          itmNumber = number;
     public int getItmNumber() // method to get item number
          return itmNumber;
     public void setUnits(int unit) // method to set number of units
          units = unit;
     public int getUnits() // method to get number of units
          return units;
     public void setPrice(double each) // method to set price
          price = each;
     public double getPrice() // method to get price
          return price;
     public double calcValue() // method to set value
          return units * price;
} // end class Product
class ProductAdd extends Product
     private String feature; // variable for added feature
     public ProductAdd(String name, int number, int unit, double each, String addFeat)
          // call to superclass Product constructor
          super(name, number, unit, each);
          feature = addFeat;
     }// end constructor
          public void setFeature(String addFeat) // method to set added feature
               feature = addFeat;
          public String getFeature() // method to get added feature
               return feature;
          public double calcValueRstk() // method to set value and add restock fee
               return units * price * 0.05;
          public String toString()
               return String.format("%s%d%d$%.2f%s$%.2f$%.2f",
               getProdName(), getItmNumber(), getUnits(), getPrice(), getFeature(), calcValue(), calcValueRstk());
} // end class ProductAdd
class FontJPanel extends JPanel
     // display welcome message
     public void paintComponent( Graphics g )
          super.paintComponent( g ); //call superclass's paintComponent
          // set font to Monospaced (Courier), italic, 12pt and draw a string
          g.setFont( new Font( "Monospaced", Font.ITALIC, 12 ) );
          g.drawString( "min", 90, 70 );
          // set font to Serif (Times), bold, 24pt and draw a string
          g.setColor( Color.RED );
          g.setFont( new Font( "Serif", Font.BOLD, 24 ) );
          g.drawString( "OFFICE", 60, 60 );
     } // end method paintComponent
} // end class FontJPanel