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Java - Linking a JTextField variable with another class variable

What I want to achieve is very simple.
I have 2 classes. "SpeedingTicket" & "SpeedingTicket GUI".
Inside my GUI I have 1 textbox name txtSpeedLimit & a button.
Inside my SpeedingTicket class I have a variable "int speedingTicket".
Inside my SpeedingTicket class I also have a get & set method for "speedingTicket".
I know how to get and set text using JTextFields, but I want to be able to:
receive input from the "txtSpeedLimit", and store that value into the "txtSpeedLimit" instance variable in the "SpeedTicket" class. I can then check for validation etc when I come to adding the vehicle speed.
Maybe this isn't the most efficient way of dealing with this program. Maybe I should scrap the instance variables in SpeedingTicket, and deal with it all in the GUI.
Any advice would be hugely appreciated.
Basically what I'm trying to do is this:
class confirmHandler implements ActionListener{
public void actionPerformed(ActionEvent e){
String val = txtSpeedLimit.getText();
int realNum = speed.getSpeedLimit() = txtSpeedLimit; < but obviously that doesn't work, but I want the textbox link to the variable.
EDIT: If we take away the GUI, all I want my program to do is the following:
Speed Limit: 50 < enterd via textfield
Speed: 60 < entered via textfield
if the speed is blah blah (ive already coded this).. then output a result to one of my labels.
I achieved this without making a GUI and making it only console based, but instead of the user typing it via the console, I want it to be typed via textfields.
THe values that are entered into the textfields should be stored in the two variables (speed and speedlimit) that are in the SpeedingTicket class.

You can update a value in:
public class SpeedingTicket {
int speedingTicket;
public SpeedingTicket() {
speedingTicket = 500;
}
public int getSpeedingTicket() {
return speedingTicket;
}
}
by:
public class SpeedingTicketGUI extends JPanel{
SpeedingTicket st;
SpeedingTicketGUI() {
st = new SpeedingTicket();
setLayout(new FlowLayout(FlowLayout.LEFT));
JTextField txtField = new JTextField(10);
txtField.setText(""+st.getSpeedingTicket());
add(txtField);
JButton btn = new JButton("Update");
btn.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
setSpeedingTicket(txtField.getText());
}
});
add(btn);
}
private void setSpeedingTicket(String text) {
try {
int speedTicket = Integer.parseInt(text);
st.setSpeedingTicket(speedTicket);
System.out.println("Speeding ticket set to " +st.getSpeedingTicket());
} catch (NumberFormatException ex) {
System.out.println("Invalid value " +text);
ex.printStackTrace();
}
}
public static void main(String[] args){
JFrame frame = new JFrame("Speeding Ticket");
frame.setSize(400,100);
frame.add(new SpeedingTicketGUI());
frame.setVisible(true);
}
}

You don't need to store values in JText or any GUI componenets...
Use global static variables. For example:
public static int speed_limit;
You can access this variable from ANY method,class, etc.

There are multiple ways to do it.
You can detect textfield changes by using a DocumentListener or if you want (not recommended) by a KeyListener.
The Listener could be implemented directly by your gui class or by your other class. If you want more abstraction you could implement the DocumentListener by your gui class and create a method
public void addSpeedChangeListener(SpeedChangeListener scl) {
this.speedChangeListeners.add(scl);
}
Your SpeedChangeListener could be very simple:
public interface SpeedChangeListener {
public void speedChanged(int value);
}
Then your second class implements the SpeedChangeListener and calls addSpeedChangeListener(this) on your gui class. Inside the gui class, your document listener calls speedChanged(val) for every listener registered.
EDIT
You can also use the Button and call the speedChanged on every listener inside the actionPerformed method of the ActionListener.

I think it would be easier to use a JOptionDialog which pop ups when the button is clicked. That way you can easily get input and also validate the input straight away.

Is there a way to disable all buttons with a method?

This is a lab for school that I'm struggling with, the code is making a game of hangman, and when the "brain" program says the game is over, all of the letter buttons are supposed to be disabled.
relevant code sections:
the buttons:
class ActionButton extends JButton implements ActionListener{
private String name;
private char t;
public ActionButton(String s){
super(s);
name = s;
t = name.charAt(0);
}
#Override
public void actionPerformed(ActionEvent e) {
ido.newLetter(t);
this.setEnabled(false);
LovesMePanel.this.update();
}
}
the update method:
public void update(){
answers = ido.getAnswer();
flower.setTriesLeft(ido.getTriesLeft());
progress.setText(answers);
if(ido.gameOver()){
// This is where I need to deactivate the buttons
if(ido.hasWon()){
}
}
else if(triesLeft == 0){
}
}
the buttons are all created in a loop in the LoveMePanel that holds all of the other panels. Is there a way to reference them all or disable them all when the game is over?
If not, how should I change my code so that it would be possible to do that?

If you put your buttons in a Collection, you can iterate through them and disable them all that way. I.e.,
for (JButton b : myButtons) {
b.setEnabled(false)
}
If not, you have 26 disable statements to write.

See the setEnabled() method for JButton. You can:
Add your Buttons to an ArrayList while creating them and then iterate over it and disable one by one
Get children of a JPanel, iterate over them, check if it's a button and disable it
Put a Glass Pane on top of your Burrons to intercept the incoming events
Feel free to choose the one you like best.

how about getting the children of the root panel by calling getComponents and iterating over them recursively and finding JButtons and disabling them as you find them?

relations between classes

I'm having a difficults to add rows to a table that located in different class.
Following are the classes structure:
The dashed arrow is the desired relation that I dont manage to have
in the AddPanel class I have a fileds and Addbutton.
when clicking the addButton I first creating an instance of Product (class located in Logic Package). Then I need to add row to the table (Using the TableModel.AddRow method).
Following are the GUI Looks (the focused tab is AddPannel):
I tried different approches but non of them were successed.
My last attempt was to create in the Table class the following method:
public void AddRow(Product p) {
tbmStock.addRow(new Object[] { p.getExternalId(), p.getName(),
p.getAmount(), p.getPriceForMe(), p.getPriceForCustomer() });
}
In addition, in the AddPanel class I tried to add the following method:
private void AddButtonAction() {
btnAddProduct.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
try {
Product p = new Product(txtName.getText(), txtExternalID
.getText(), Integer.parseInt(txtAmount.getText()),
Double.parseDouble(txtPriceForMe.getText()),
Double.parseDouble(txtPriceForCustomer.getText()),
Integer.parseInt(txtFromYear.getText()), Integer
.parseInt(txtToYear.getText()), Integer
.parseInt(txtSupplier.getText()), Integer
.parseInt(txtCarType.getText()));
AddRow(p); //This call doesn't compiles
}
catch (Exception e1){
JOptionPane.showMessageDialog(null,"Error");
}
}
});
}
Any suggestions ? (actually I'm not sure even that my structure is good :S )

Provide a custom event and event listener. If you create a new product fire the event and notify all listeners. The MainPanel (assuming that's where you create the instance of AddPanel), should register a listener. In this listener you then can update the table as the MainPanel has access to the table.
This is also known as the Mediator pattern.
Some pointers:
Create an event class, e.g. ProductCreatedEvent extends EventObject. Pass the Product as an argument to the constructor and make it accessible with a getter.
Create an event listener class: interface ProductCreatedEventListener extends EventListener. Provide a method such as productCreated(ProductCreatedEvent productCreatedEvent).
In the AddPanel add something like:
private final List<ProductCreatedEventListener> productCreatedEventListeners = new ArrayList<>();
...
public void addProductCreatedEventListener(ProductCreatedEventListener productCreatedEventListener){
productCreatedEventListeners.add(productCreatedEventListener);
}
public void removeProductCreatedEventListener(ProductCreatedEventListener productCreatedEventListener){
productCreatedEventListeners.remove(productCreatedEventListener);
}
private void fireProductCreatedEvent(ProductCreatedEvent event){
for (ProductCreatedEventListener productCreatedEventListener : productCreatedEventListeners){
productCreatedEventListener.productCreated(event);
}
}
Replace:
AddRow(p); //This isn't working
with
fireProductCreatedEvent(new ProductCreatedEvent(AddPanel.this, p));

Creating new object of a class on button click / actionEvent

Found solution
decided it was easier to simply make a method outside of the actionListener called chairPrice which can be incremented by a method called getItemPrice(). This has been used to calculate the total price of items and works 100%

You need to use the Object.equals() method.
#Override
public void actionPerformed(ActionEvent buttonClick)
{
if(buttonClick.getSource().equals(guiButtons[0])) //if user clicks on 'add chair'
{
Chair chair = new Chair();
}
}
Edit in response to the OP's comment
I'm not exactly sure what you're wanting. myChair isn't the name of your chair. It's the name of the variable. It has no effect on Chair at all. If you want to make a new Chair object and have it available for the whole class, you're going to need to either add a new field variable or make a list of Chair.
public class GuiClass extends JPanel implements ActionListener
{
List<Chair> chairs = new ArrayList<Chair>(Arrays.asList(new Chair()));
Desk myDesk = new Desk();
Table myTable = new Table();
#Override
public void actionPerformed(ActionEvent buttonClick)
{
if(buttonClick.getSource().equals(guiButtons[0])) //if user clicks on 'add chair'
{
chairs.add(new Chair());
}
}
}

Removing an item from the JList using ListModel as model type

I have the JList which is using ListModel and not the DefaultListModel. I don't want to change the type now because I am using this in many places. I want to remove a selected item from the same list. How do i do this? I am using the following code but its not working for me.
made_list.removeSelectionInterval(
made_list.getSelectedIndex(), made_list.getSelectedIndex());
--EDIT--
I am using the following code when I create my list:
made_list = new javax.swing.JList();
made_list.setModel(new DefaultListModel());
And then in the JButton mouseclick event, I am using the following code to remove the selected item from the list when the button is pressed
private void removeActionPerformed(java.awt.event.ActionEvent evt) {
//made_list.removeSelectionInterval(made_list.getSelectedIndex(),
//made_list.getSelectedIndex());
System.out.println(made_list.getModel());
DefaultListModel model = (DefaultListModel)made_list.getModel();
model.remove(1);
}

removeSelectionInterval removes nothing from the model or the list except the selection interval. The list items remain unscathed. I'm afraid that you're either going to have to extend your ListModel and give it a removeItem(...) method as well as listeners and the ability to fire notifiers, etc... a la AbstractListModel -- quite a lot of work! If it were my money, though, I'd go the easy route and simply use a DefaultListModel for my model as it is a lot safer to do it this way, a lot easier, and will take a lot less time. I know you state that you don't want to use these, but I think you'll find it a lot easier than your potential alternatives.
An example of an SSCCE is something like this:
import java.awt.event.*;
import javax.swing.*;
public class Foo1 {
private String[] elements = {"Monday", "Tueday", "Wednesday"};
private javax.swing.JList made_list = new javax.swing.JList();
public Foo1() {
made_list.setModel(new DefaultListModel());
for (String element : elements) {
((DefaultListModel) made_list.getModel()).addElement(element);
}
JButton removeItemBtn = new JButton("Remove Item");
removeItemBtn.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
removeActionPerformed(e);
}
});
JPanel panel = new JPanel();
panel.add(new JScrollPane(made_list));
panel.add(removeItemBtn);
JOptionPane.showMessageDialog(null, panel);
}
private void removeActionPerformed(ActionEvent e) {
System.out.println("made_list's model: " + made_list.getModel());
System.out.println("Model from a fresh JList: " + new JList().getModel());
DefaultListModel model = (DefaultListModel) made_list.getModel();
if (model.size() > 0) {
model.remove(0);
}
}
public static void main(String[] args) {
new Foo1();
}
}

You've been given a link to different sections of the Swing tutorial in the past to help solve problems. This was done for a reason. It helps solve your current problem. It gives you a reference for future problems.
All you need to do is look at the Table of Contents for the Swing tutorial and you will find a section on "How to Use Lists" which has a working example that adds/removes items from a list. Please read the tutorial first.
Or if you can't remember how to find the Swing tutorial then read the JList API where you will find a link to the same tutorial.

//First added item into the list
DefaultListModel dlm1=new DefaultListModel();
listLeft.setModel(dlm1);
dlm1.addElement("A");
dlm1.addElement("B");
dlm1.addElement("C");
// Removeing element from list
Object[] temp=listRight.getSelectedValues();
if(temp.length>0)
{
for(int i=0;i<temp.length;i++)
{
dlm1.removeElement(temp[i]);
}
}