first of all my Java experience isn't great. Basically when i click the button "Update" it should change the field in the hashmap to what the user has chosen in the Text Field. However when i press update it gives me a NullPointerException at this line:
foundManufacturer.setManufacturer(txtManufacturer.getText().toString().trim());
What can i do to fix this so that it updates the field? Here is my code. The Problem i am having is in the ActionPerformed Method at the bottom
package partA;
import java.awt.Color;
import java.awt.Component;
import java.awt.Font;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.HashMap;
import javax.swing.*;
public class EditProductDetails extends JFrame implements ActionListener
{
private JLabel lblProductID, lblManufacturer, lblName, lblCategory, lblCost,
lblSellingPrice;
private JTextField txtProductID, txtManufacturer, txtName, txtCost,
txtSellingPrice;
private JComboBox cmbCategory;
private JButton btnUpdate, btnSearch, btnExit;
private JTextArea txtArea;
private HashMap<String, Stock> products;
public EditProductDetails(HashMap<String, Stock> sItems)
{
products = sItems;
cmbCategory = new JComboBox();
String[]supplies = {"Nutrition Bars", "Sports Suplements", "Vitamins",
"Weight Loss", "Accessories"};
cmbCategory = new JComboBox(supplies);
btnUpdate = new JButton("Update Product");
btnUpdate.addActionListener(this);
btnSearch = new JButton("Search!");
btnSearch.addActionListener(this);
btnExit = new JButton("Exit");
btnExit.addActionListener(this);
txtProductID = new JTextField("");
txtManufacturer = new JTextField("");
txtName = new JTextField("");
txtCost = new JTextField("");
txtSellingPrice = new JTextField("");
txtArea = new JTextArea("");
txtArea.setEnabled(false);
txtArea.setBackground(Color.DARK_GRAY);
txtArea.setForeground(Color.YELLOW);
lblProductID = new JLabel("Product ID: ");
lblProductID.setFont(new Font("SansSerif",Font.BOLD,14));
lblManufacturer = new JLabel("New Manufacturer: ");
lblManufacturer.setFont(new Font("SansSerif",Font.BOLD,14));
lblName = new JLabel("New Name: ");
lblName.setFont(new Font("SansSerif",Font.BOLD,14));
lblCategory = new JLabel("New Category: ");
lblCategory.setFont(new Font("SansSerif",Font.BOLD,14));
lblCost = new JLabel("New Cost: ");
lblCost.setFont(new Font("SansSerif",Font.BOLD,14));
lblSellingPrice = new JLabel("New Selling Price: ");
lblSellingPrice.setFont(new Font("SansSerif",Font.BOLD,14));
getContentPane().setLayout(new GridBagLayout());
addComp(lblProductID, 0, 0, 2, 1, 1, 1);
addComp(lblManufacturer, 0, 2, 2, 1, 1, 1);
addComp(lblName, 0, 3, 2, 1, 1, 1);
addComp(lblCategory, 0, 4, 2, 1, 1, 1);
addComp(lblCost, 0, 5, 2, 1, 1, 1);
addComp(lblSellingPrice, 0, 6, 2, 1, 1, 1);
addComp(txtProductID, 2, 0, 2, 1, 1, 1);
addComp(txtManufacturer, 2, 2, 2, 1, 1, 1);
addComp(txtName, 2, 3, 2, 1, 1, 1);
addComp(cmbCategory, 2, 4, 2, 1, 1, 1);
addComp(txtCost, 2, 5, 2, 1, 1, 1);
addComp(txtSellingPrice, 2, 6, 2, 1, 1, 1);
addComp(txtArea, 5, 0, 2, 2, 1, 1);
addComp(btnSearch, 0, 1, 4, 1, 1, 1);
addComp(btnUpdate, 0, 7, 4, 1, 1, 1);
addComp(btnExit, 0, 8, 4, 1, 1, 1);
}
private void addComp(Component c, int gridx, int gridy,
int width, int height,
int weightx, int weighty)
{
GridBagConstraints gc = new GridBagConstraints();
gc.fill = GridBagConstraints.BOTH;
gc.insets = new Insets(5, 5, 5, 5);
gc.gridx = gridx;
gc.gridy = gridy;
gc.gridwidth = width;
gc.gridheight = height;
gc.weightx = weightx;
gc.weighty = weighty;
getContentPane().add(c, gc);
}
@Override
public void actionPerformed(ActionEvent event)
{
if(event.getSource()==btnUpdate)
{
String findProductID="", findManufacturer="", findName="", findCategory="",
findCost="", findSellingPrice="";
Stock foundItem, foundManufacturer, foundName, foundCategory, foundCost,
foundSellingPrice;
findProductID = txtProductID.getText().trim();
findManufacturer = txtManufacturer.getText().trim();
findName = txtName.getText().trim();
findCategory = cmbCategory.getSelectedItem().toString().trim();
findCost = txtCost.getText().trim();
findSellingPrice = txtSellingPrice.getText().trim();
foundItem=products.get(findProductID);
foundManufacturer=products.get(findManufacturer);
foundName=products.get(findName);
foundCategory=products.get(findCategory);
foundCost=products.get(findCost);
foundSellingPrice=products.get(findSellingPrice);
foundManufacturer.setManufacturer(txtManufacturer.getText().toString().trim());
foundName.setName(txtName.getText().toString().trim());
foundCategory.setCategory(cmbCategory.getSelectedItem().toString().trim());
foundCost.setCost(Integer.parseInt(txtCost.getText().toString().trim()));
foundSellingPrice.setSellingPrice(Integer.parseInt(txtSellingPrice.getText().toString().trim()));
JOptionPane.showMessageDialog
(null, "The product with ID " + txtProductID.getText() + " was edited successfully!");
}
if(event.getSource()==btnExit)
{
this.setVisible(false);
}
if(event.getSource()==btnSearch)
{
txtArea.setText("");
String s;
// Add a header
s="Product ID. Manufacturer Name Category No.Sold No.In Stock Cost Sell Price\n";
txtArea.append(s);
s="--------------------------------------------------------------------------------------------------------------------------\n";
txtArea.append(s);
String findProductID="";
Stock foundItem;
findProductID=txtProductID.getText().trim();
foundItem=products.get(findProductID);
txtArea.append(foundItem.toString());
}
}
}
