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2347

answers:

3

This is homework. Beginning Java class. Still wrapping my head around this stuff.

The project is to make an Inventory Management System.

I have everything figured out except how to make this button change the text in a JTextField. It needs to add info from an array of a product (DVD's in this case). The book talks about different ways to manage things like font, position and state of a JTextField but it does not cover formatting or calling a method for the text.

Here is an example of what I want to do using a JTextArea. This is essentially what I want to do with my JTextFields.

   ...
    // setup the interface    

 JPanel panel = new JPanel();
 txt = new JTextArea(15,40);
 txt.setEditable(false);//user shouldn't change it
 panel.add(txt);

 JButton next = new JButton("Next");

 panel.add(next);

 getContentPane().add(panel);

 displayDVD();
 }
 // view software
 public void displayDVD() {
       txt.setText("DVD Details:\n");
    txt.append("Item number: " + inv.get(currentDisplay).getItem() + "\n");
    txt.append("DVD name: " + inv.get(currentDisplay).getName() + "\n");
    txt.append("Units in stock: " + inv.get(currentDisplay).getUnits() + "\n");
    txt.append("Price: $" +                                              
       String.format("%.2f",inv.get(currentDisplay).getPrice()) + "\n");
    txt.append("Total value: $" +                             
       String.format("%.2f",inv.get(currentDisplay).value()) + "\n");
    txt.append("Fee: $" + String.format("%.2f",inv.get(currentDisplay).fee()) + "\n\n");

    txt.append("Total value: $" + String.format("%.2f",inv.value()));
 }

And here is my actual code so far

// GUI with navigation amd file manipulation buttons
import javax.swing.*; // provides basic window features
import java.awt.event.*;
import java.awt.GridLayout;
import java.awt.BorderLayout;

public class AppGUI extends JFrame 
{
   private Inventory inv;    
 private int currentDisplay = 0; 

   private JPanel topButtonJPanel;
 private JButton topButtons[]; 

 private JPanel labelJPanel;
 private JLabel labels[]; 

 private JPanel fieldJPanel;
 private JTextField fields[];

   private JPanel buttonJPanel;
 private JButton buttons[]; 

   // LabelFrame constructor adds JLabels to JFrame
   public AppGUI()
   {
      super( "Inventory Program v.5" );
      setLayout( new BorderLayout() ); // set frame layout
  setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);// quit if the window is closed

  // initialize values
  RatedDVD d1 = new RatedDVD(1, "The Invisible Man", 0, 4999.99, "PG");
  RatedDVD d2 = new RatedDVD(2, "The Matrix", 1, 13.01, "PG13");
  RatedDVD d3 = new RatedDVD(3, "Se7en", 7, 11.11, "R");
  RatedDVD d4 = new RatedDVD(4, "Oceans Eleven", 11, 9.02, "PG13");
  RatedDVD d5 = new RatedDVD(5, "Hitch Hikers Guide to the Galaxy", 42, 10.00, "G"); 

  // create inv and enter values
  inv = new Inventory();
  inv.add(d1);
  inv.add(d2);
  inv.add(d3);
  inv.add(d4);
  inv.add(d5);

  inv.sort();

  topButtons = new JButton[ 6 ]; // create topButtons array
  topButtonJPanel = new JPanel(); // set up panel
  topButtonJPanel.setLayout( new GridLayout( 1, topButtons.length, 2, 2 ) );
  topButtons[0] = new JButton( "Load file" );
  topButtons[1] = new JButton( "Add" );
  topButtons[2] = new JButton( "Modify" );
  topButtons[3] = new JButton( "Delete" );
  topButtons[4] = new JButton( "Search" );
  topButtons[5] = new JButton( "Save" );

  for(int count=0;count<topButtons.length;count++){topButtonJPanel.add(topButtons[count]);}
  //add( topButtonJPanel, BorderLayout.NORTH ); // this is for next weeks assignment

  labels = new JLabel[8];
  labelJPanel = new JPanel();
  labelJPanel.setLayout( new GridLayout( labels.length, 1 ));
  labels[0] = new JLabel( "Item ID" );
  labels[1] = new JLabel( "Name" );
  labels[2] = new JLabel( "Rating" );
  labels[3] = new JLabel( "# in Stock" );
  labels[4] = new JLabel( "Price" );
  labels[5] = new JLabel( "Restocking Fee" );//[DEBUG] ref actual Variable
  labels[6] = new JLabel( "Inventory Value with Fee (5%)" );
  labels[7] = new JLabel( "Total Value with Fee(for all items)" );

  for(int count=0;count<labels.length;count++){labelJPanel.add(labels[count]);}
  add( labelJPanel, BorderLayout.WEST );

  fields = new JTextField[8];
  fieldJPanel = new JPanel();
  int spaces = 28;
  fieldJPanel.setLayout( new GridLayout( labels.length, 1 ));
  fields[0] = new JTextField( "", spaces );
  fields[1] = new JTextField( "", spaces );
  fields[2] = new JTextField( "", spaces );
  fields[3] = new JTextField( "", spaces );
  fields[4] = new JTextField( "", spaces );
  fields[5] = new JTextField( "", spaces );
  fields[6] = new JTextField( "", spaces );
  fields[7] = new JTextField( "", spaces );

  for(int count=0;count<fields.length;count++)
  {
   fields[count].setEditable( false );
   fieldJPanel.add(fields[count]);
  }
  add( fieldJPanel, BorderLayout.EAST );

  buttons = new JButton[ 5 ]; // create buttons array
  buttonJPanel = new JPanel(); // set up panel
  buttonJPanel.setLayout( new GridLayout( 1, buttons.length, 2, 2 ) );
  buttons[0] = new JButton( "First" ); 
  buttons[0].addActionListener(new ActionListener() {
   public void actionPerformed(ActionEvent e) {
    if (currentDisplay != 0)currentDisplay = 0; //advance to the end
    }
   });
  buttons[1] = new JButton( "Prev" );
  buttons[1].addActionListener(new ActionListener() {
   public void actionPerformed(ActionEvent e) {
    if (currentDisplay != 0)currentDisplay--; //advance to the end
     else currentDisplay = (inv.size()-1); 
    }
   });
  Icon bug1 = new ImageIcon( getClass().getResource( "bug1.gif" ) );
  buttons[2] = new JButton( bug1 );
  buttons[3] = new JButton( "Next" );
  buttons[3].addActionListener(new ActionListener() {
   public void actionPerformed(ActionEvent e) {
    if (currentDisplay < inv.size()-1)currentDisplay++; //advance to the end
     else currentDisplay = 0;    stkover
   }}); 
  buttons[4] = new JButton( "Last" );
  buttons[4].addActionListener(new ActionListener() {
   public void actionPerformed(ActionEvent e) {
    if (currentDisplay != inv.size()-1)currentDisplay = inv.size()-1; //advance to the end
     else currentDisplay = (inv.size()-1); 
    }
   });

  for(int count=0;count<buttons.length;count++){buttonJPanel.add(buttons[count]);}
  add( buttonJPanel, BorderLayout.SOUTH );
 }// end method

}// end class AppGUI

Any hints tips or nudges appreciated. Don't do it all for me though please.

A: 

For a cross-reference like "my button changes my testbox", the idea is to give to the button (the controller, the code that will get activated when clicked) a reference to the textbox. So when the button is pressed, it can change the textbox.

They are many improvements possible, but that's the basic idea.

KLE
Your response confuses me. The wording I think. I know to give the button the code to control the JTextField. What I am asking is for the method or syntax to do it with like fields[i]setString(inv.get(currentDisplay).getItem()) or something
lazfish
A: 

I guess I don't understand the question.

You know how to add multiple pieces of text to a single component.

txt.append("Item number: " + inv.get(currentDisplay).getItem() + "\n"); 
txt.append("DVD name: " + inv.get(currentDisplay).getName() + "\n");

So why it is so hard to add a single piece of text to multiple components?

itemTextField.setText( inv.get(currentDisplay).getItem() );
nameTextField.setText( inv.get(currentDisplay).getName() );
camickr
I am trying to use JTextfield instead of JTextArea
lazfish
I will be needind to change 8 JTextfields with each button. How would I do that? I am looking up this setText method now.
lazfish
+1  A: 

You add an action listener to the button (so that it will listen to the button action (click)). Then program that action to change the TextField value.

final JButton    aButton    = ...;
final JTextField aTextField = ...;
final String     aNewText   = "New TextField Value";

aButton.addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent e) {
        aTextField.setText(aNewText);
    }
});

Observe that variables accessed with in 'actionPerformed' must be final (except the fields).

Hope this helps.

NawaMan
Ok so I need to change 8 JTextFields with each button. Next week (tomorrow) I will be working on a function to modify. How would I approach that?
lazfish
If you have more than one button acting similarly, they can share the same action listener. First make your AppGUI implements ActionListener and add a method call "public void actionPerformed(ActionEvent e)" to it. In the method, you can call e.getSource() (See http://java.sun.com/javase/6/docs/api/java/util/EventObject.html#getSource()) to see what button is the action originated and react accordingly.I suggest you to look at the tutorial for this for more info: http://java.sun.com/docs/books/tutorial/uiswing/components/button.html.Enjoy :D.
NawaMan