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Thread: Help with an error in code

  1. #1
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    Default Help with an error in code

    I am a newbie to the java world. Can you please assist me by telling me why I am getting this error in my code. I know I am missing something but cant figure it out. The error is in the line when I use :

    volumeField.setText(df.format(volume)); The error is df cannot be resolved. I'd appreciate any help that you can give.

    import java.awt.Color;
    import java.awt.Container;
    import java.awt.FlowLayout;
    import java.awt.Font;
    import java.awt.event.ActionEvent;
    import java.awt.event.ActionListener;
    import java.awt.event.ItemEvent;
    import java.awt.event.ItemListener;
    import java.io.BufferedReader;
    import java.io.BufferedWriter;
    import java.io.File;
    import java.io.FileReader;
    import java.io.FileWriter;
    import java.io.IOException;
    import java.text.DecimalFormat;
    import java.text.SimpleDateFormat;
    import java.util.Calendar;
     
    import javax.swing.BorderFactory;
    import javax.swing.ButtonGroup;
    import javax.swing.JButton;
    import javax.swing.JComboBox;
    import javax.swing.JDialog;
    import javax.swing.JFrame;
    import javax.swing.JLabel;
    import javax.swing.JPanel;
    import javax.swing.JRadioButton;
    import javax.swing.JScrollPane;
    import javax.swing.JTabbedPane;
    import javax.swing.JTextArea;
    import javax.swing.JTextField;
    public class LandScape {
     
    	/**
    	 * Application starts here.
    	 */
    	public static void main(String[] args) {
    	new LandScape ();
    	}
    		class Landscape extends JFrame{
    			private JTabbedPane tabs;
    			private JPanel generalPanel;			
    			private JPanel customersPanel;
    			private JPanel poolsPanel;
    			private JPanel hotTubsPanel;
     
    			private void initializeComponents() {
    				Container pane = getContentPane();
     
    				tabs = new JTabbedPane();
     
    				buildGeneralTab();
    				buildCustomersTab();
    				builPoolsTab();
    				buildHotTubsTab();
     
    				tabs.add("General", generalPanel);
    				tabs.add("Customers", customersPanel);
    				tabs.add("Pools", poolsPanel);
    				tabs.add("Hot Tubs", hotTubsPanel);
     
    				pane.add(tabs);
    			}
     
    			private void buildHotTubsTab() {
    				hotTubsPanel = new JPanel(new FlowLayout());
     
    				final JRadioButton roundTub = new JRadioButton("Round Tub");
    				final JRadioButton ovalTub = new JRadioButton("Oval Tub");
     
    				roundTub.setSelected(true);
     
    				ButtonGroup group = new ButtonGroup();
    				group.add(roundTub);
    				group.add(ovalTub);
     
    				hotTubsPanel.add(roundTub);
    				hotTubsPanel.add(ovalTub);
     
    				hotTubsPanel.add(new JLabel("Enter the tub's length (ft): "));
    				final JTextField lengthField = new JTextField(10);
    				hotTubsPanel.add(lengthField);
     
    				final JLabel widthLabel = new JLabel("Enter the tub's width (ft): ");
    				widthLabel.setEnabled(false);
    				hotTubsPanel.add(widthLabel);
     
    				final JTextField widthField = new JTextField(10);
    				widthField.setEnabled(false);
    				hotTubsPanel.add(widthField);
     
    				hotTubsPanel.add(new JLabel("Enter the tub's depth (ft): "));
    				final JTextField depthField = new JTextField(10);
    				hotTubsPanel.add(depthField);
     
    				JButton calculateVolume = new JButton("Calculate Volume");
    				calculateVolume.setMnemonic('C');
    				hotTubsPanel.add(calculateVolume);
    				hotTubsPanel.add(createExitButton());
     
    				hotTubsPanel.add(new JLabel("The tub's volume is (ft^3): "));
    				final JTextField volumeField = new JTextField(10);
    				volumeField.setEditable(false);
    				hotTubsPanel.add(volumeField);
     
    				final JTextArea messageArea = createMessageArea(1, 25,
    						"Width will be set to the same value as length");
    				hotTubsPanel.add(messageArea);
     
    				calculateVolume.addActionListener(new ActionListener() {
    					public void actionPerformed(ActionEvent e) {
    						if (roundTub.isSelected()) {
    							widthField.setText(lengthField.getText());
    						}
     
    						ValidationResult result = validateFields(new JTextField[] {
    								lengthField, widthField, depthField });
     
    						String errors = "";
    						if (result.filled != 3) {
    							errors += "Please fill out all fields! ";
    						}
    						if (result.valid != 3 && result.filled != result.valid) {
    							errors += "Please enter valid numbers!";
    						}
     
    						if (errors != "") {
    							messageArea.setText(errors);
    							messageArea.setVisible(true);
    						} else {
    							messageArea.setVisible(false);
     
    							double length = Double.parseDouble(lengthField.getText());
    							double width = Double.parseDouble(widthField.getText());
    							double depth = Double.parseDouble(depthField.getText());
     
    							double volume;
    							if (roundTub.isSelected()) {
    								volume = Math.PI * Math.pow(length / 2.0, 2) * depth;
    							} else {
    								volume = Math.PI * Math.pow(length * width, 2) * depth;
    							}
    							volumeField.setText(df.format(volume));
    						}
    					}
    				});
     
    				ActionListener tubsListener = new ActionListener() {
    					public void actionPerformed(ActionEvent e) {
    						if (e.getSource() == roundTub) {
    							widthLabel.setEnabled(false);
    							widthField.setEnabled(false);
    							widthField.setText(lengthField.getText());
    							messageArea.setText("Tub's width set to length");
    							messageArea.setVisible(true);
    						} else if (e.getSource() == ovalTub) {
    							widthLabel.setEnabled(true);
    							widthField.setEnabled(true);
    							messageArea.setVisible(false);
    						}
    					}
    				};
    				roundTub.addActionListener(tubsListener);
    				ovalTub.addActionListener(tubsListener);
    			}
     
    			private void builPoolsTab() {
    				poolsPanel = new JPanel(new FlowLayout());
     
    				poolsPanel.add(new JLabel("Enter the pool's length (ft): "));
    				final JTextField lengthField = new JTextField(10);
    				poolsPanel.add(lengthField);
     
    				poolsPanel.add(new JLabel("Enter the pool's width (ft): "));
    				final JTextField widthField = new JTextField(10);
    				poolsPanel.add(widthField);
     
    				poolsPanel.add(new JLabel("Enter the pool's depth (ft): "));
    				final JTextField depthField = new JTextField(10);
    				poolsPanel.add(depthField);
     
    				JButton calculateVolume = new JButton("Calculate Volume");
    				calculateVolume.setMnemonic('C');
    				poolsPanel.add(calculateVolume);
    				poolsPanel.add(createExitButton());
     
    				poolsPanel.add(new JLabel("The pool's volume is (ft^3): "));
    				final JTextField volumeField = new JTextField(10);
    				volumeField.setEditable(false);
    				poolsPanel.add(volumeField);
     
    				final JTextArea messageArea = createMessageArea(2, 20, "");
    				poolsPanel.add(messageArea);
     
    				calculateVolume.addActionListener(new ActionListener() {
    					public void actionPerformed(ActionEvent e) {
    						ValidationResult result = validateFields(new JTextField[] {
    								lengthField, widthField, depthField });
     
    						String errors = "";
    						if (result.filled != 3) {
    							errors += "Please fill out all fields! ";
    						}
    						if (result.valid != 3 && result.filled != result.valid) {
    							errors += "Please enter valid numbers!";
    						}
     
    						if (errors != "") {
    							messageArea.setText(errors);
    							messageArea.setVisible(true);
    						} else {
    							messageArea.setVisible(false);
     
    							double length = Double.parseDouble(lengthField.getText());
    							double width = Double.parseDouble(widthField.getText());
    							double depth = Double.parseDouble(depthField.getText());
     
    							double volume = length * width * depth;
     
    							volumeField.setText(df.format(volume));
    						}
    					}
    				});
    			}
     
     
     
     
     
    			private void buildCustomersTab() {
    				customersPanel = createContactPanel("Customer", "customer.txt");
    			}
     
     
     
     
     
     
    			private void buildGeneralTab() {
    				generalPanel = new JPanel(new FlowLayout());
    				String currentTime = SimpleDateFormat.getInstance().format(
    						Calendar.getInstance().getTime());
    				generalPanel.add(new JLabel("Today's Date: " + currentTime));
    				generalPanel.add(createExitButton());
    			}
     
     
    			private JButton createExitButton() {
    				JButton exitButton = new JButton("Exit");
    				exitButton.setMnemonic('x');
    				exitButton.addActionListener(new ActionListener() {
    					public void actionPerformed(ActionEvent e) {
    						System.exit(0);
    					}
    				});
    				return exitButton;
    			}
     
     
    			@SuppressWarnings("unused")
    			private JTextField createTitleField(String text, int length) {
    				JTextField tf = new JTextField(length);
    				tf.setEditable(false);
    				tf.setFocusable(false);
    				tf.setText(text);
    				return tf;
    			}
     
     
    			private String loadDataFromFile(String fileName) {
    				String data = "";
     
    				try {
    					BufferedReader reader = new BufferedReader(new FileReader(fileName));
    					while (reader.ready()) {
    						data += reader.readLine() + "\n";
    					}
    					reader.close();
    				} catch (IOException e) {
    				}
     
    				return data;
    			}
     
     
    			private JPanel createContactPanel(final String contactName,
    					final String fileName) {
     
    				JPanel pane = new JPanel(new FlowLayout());
     
    				final JTextArea customerDisplay = new JTextArea(8, 25);
    				customerDisplay.setLineWrap(true);
    				customerDisplay.setEditable(false);
    				pane.add(new JScrollPane(customerDisplay));
     
    				pane.add(createExitButton());
     
    				JButton addCustomerButton = new JButton("Add " + contactName);
    				addCustomerButton.setMnemonic('A');
    				pane.add(addCustomerButton);
     
    				JButton refreshButton = new JButton("Refresh");
    				refreshButton.setMnemonic('R');
    				pane.add(refreshButton);
     
    				final JTextArea messageArea = createMessageArea(2, 25, "");
    				pane.add(messageArea);
     
    				addCustomerButton.addActionListener(new ActionListener() {
    					public void actionPerformed(ActionEvent e) {
    						new EditContact(contactName, fileName);
    					}
    				});
     
    				refreshButton.addActionListener(new ActionListener() {
    					public void actionPerformed(ActionEvent e) {
    						String data = loadDataFromFile(fileName);
    						if (data != "") {
    							customerDisplay.setText(data);
    							customerDisplay.setEnabled(true);
    							messageArea.setText("File " + fileName + " exists "
    									+ "and can be read from!");
    						} else {
    							customerDisplay.setText("Select Add " + contactName
    									+ " to add " + contactName.toLowerCase()
    									+ "s. Select Refresh to refresh this pane.");
    							customerDisplay.setEnabled(false);
    							messageArea.setText("File " + fileName + " does not "
    									+ "exist yet! Will be created " + "when you add "
    									+ contactName.toLowerCase() + "s!");
    						}
    					}
    				});
     
    				refreshButton.doClick();
     
    				return pane;
    			}
     
     
    			private JTextArea createMessageArea(int rows, int cols, String text) {
    				final JTextArea messageArea = new JTextArea(rows, cols);
    				messageArea.setBorder(BorderFactory.createEmptyBorder());
    				messageArea.setLineWrap(true);
    				messageArea.setWrapStyleWord(true);
    				messageArea.setFont(new Font("System", Font.PLAIN, 12));
    				messageArea.setText(text);
    				messageArea.setBackground(null);
    				messageArea.setForeground(Color.red);
    				messageArea.setEnabled(true);
    				messageArea.setFocusable(false);
    				return messageArea;
    			}
     
     
    			private class ValidationResult {
    				/** Number of non-empty fields */
    				int filled;
    				/** Number of valid fields */
    				int valid;
    			}
     
     
    			private ValidationResult validateFields(JTextField[] fields) {
    				ValidationResult result = new ValidationResult();
    				for (int i = 0; i < fields.length; i++) {
    					JTextField field = fields[i];
    					if ((field.getText() != null) && (field.getText().length() > 0)) {
    						result.filled++;
    					}
    					try {
    						Double.parseDouble(field.getText());
    						field.setBackground(Color.white);
    						result.valid++;
    					} catch (Exception e) {
    						field.setBackground(Color.orange);
    					}
    				}
    				return result;
    			}
     
     
    			private class EditContact extends JDialog {
    				private final String contactName;
    				private final String fileName;
    				private File file;
     
    				private JTextField nameField;
    				private JTextField addressField;
    				private JTextField cityField;
    				private JComboBox stateComboBox;
    				private JTextField zipField;
    				private JTextField phoneField;
    				private JTextArea messageArea;
     
     
    				public EditContact(String contactName, String fileName) {
    					super(Landscape.this, contactName + "s");
    					setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
    					setModalityType(ModalityType.APPLICATION_MODAL);
    					setSize(400, 300);
    					this.contactName = contactName;
    					this.fileName = fileName;
     
    					initializeComponents();
     
    					if (openFile()) {
    						displayMessage(null);
    					} else {
    						displayMessage("File " + fileName + " does not exist yet! "
    								+ "Will be created when you add a "
    								+ contactName.toLowerCase() + "!");
    					}
     
    					setLocationRelativeTo(null);
    					setVisible(true);
    				}
     
    				private void displayMessage(String message) {
    					if (message != null) {
    						messageArea.setVisible(true);
    						messageArea.setText(message);
    					} else {
    						messageArea.setVisible(false);
    					}
    				}
     
    				private boolean openFile() {
    					file = new File(fileName);
    					return file.exists();
    				}
     
    				private boolean deleteFile() {
    					return file.exists() && file.delete();
    				}
     
    				private boolean saveToFile() {
    					try {
    						BufferedWriter writer = new BufferedWriter(new FileWriter(file,
    								true));
     
    						writer.write("Name: " + nameField.getText() + "\n");
    						writer.write("Address: " + addressField.getText() + "\n");
    						writer.write("City: " + cityField.getText() + "\n");
    						writer.write("State: "
    								+ stateComboBox.getSelectedItem().toString() + "\n");
    						writer.write("ZIP: " + zipField.getText() + "\n");
    						writer.write("Phone: " + phoneField.getText() + "\n");
    						writer.write("\n");
     
    						writer.close();
    						return true;
     
    					} catch (IOException e) {
    						return false;
    					}
    				}
     
    				private void initializeComponents() {
    					Container pane = getContentPane();
    					pane.setLayout(new FlowLayout());
     
    					pane.add(new JLabel(contactName + " Name "));
    					nameField = new JTextField(25);
    					pane.add(nameField);
     
    					pane.add(new JLabel("Address "));
    					addressField = new JTextField(28);
    					pane.add(addressField);
     
    					pane.add(new JLabel("City "));
    					cityField = new JTextField(32);
    					pane.add(cityField);
     
    					pane.add(new JLabel("State "));
    					stateComboBox = new JComboBox(new String[] { "AL", "AK", "AZ",
    							"AR", "CA", "CO", "CT", "DE", "FL", "GA", "HI", "ID", "IL",
    							"IN", "IA", "KS", "KY", "LA", "ME", "MD", "MA", "MI", "MN",
    							"MS", "MO", "MT", "NE", "NV", "NH", "NJ", "NM", "NY", "NC",
    							"ND", "OH", "OK", "OR", "PA", "RI", "SC", "SD", "TN", "TX",
    							"UT", "VT", "VA", "WA", "WV", "WI", "WY" });
    					pane.add(stateComboBox);
     
    					pane.add(new JLabel("ZIP "));
    					zipField = new JTextField(5);
    					pane.add(zipField);
     
    					pane.add(new JLabel("Phone "));
    					phoneField = new JTextField(10);
    					pane.add(phoneField);
     
    					JButton addContactButton = new JButton("Add " + this.contactName);
    					addContactButton.setMnemonic('A');
    					addContactButton.addActionListener(new ActionListener() {
    						public void actionPerformed(ActionEvent e) {
    							if (saveToFile()) {
    								displayMessage(contactName + " added");
    							} else {
    								displayMessage("File saving error!");
    							}
    						}
    					});
    					pane.add(addContactButton);
     
    					JButton closeButton = new JButton("Close");
    					closeButton.setMnemonic('C');
    					closeButton.addActionListener(new ActionListener() {
    						public void actionPerformed(ActionEvent e) {
    							setVisible(false);
    						}
    					});
    					pane.add(closeButton);
     
    					JButton deleteFileButton = new JButton("Delete File");
    					deleteFileButton.setMnemonic('D');
    					deleteFileButton.addActionListener(new ActionListener() {
    						public void actionPerformed(ActionEvent e) {
    							if (deleteFile()) {
    								displayMessage("File " + fileName + " deleted!");
    							}
    						}
    					});
    					pane.add(deleteFileButton);
     
    					messageArea = createMessageArea(2, 30, "");
    					pane.add(messageArea);
    				}
    			}
    		}}


  2. #2
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    Default Re: Help with an error in code

    First of all, this is the Member Introductions forum. You're looking for What's Wrong With My Code? - Java Programming Forums

    Also, you never defined df nor did you initialize it.

    Even if you did, though I didn't come across it, it's probably lost when it went out of scope if you defined it inside a method.

    You probably might have meant depthfield

  3. #3
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    Default Re: Help with an error in code

    Thread moved to What's Wrong With My Code?

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