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Java swing controller view comunication don't perform

A Controller creates a new JFrame with a button. Using the actionListener is getting the order correctly but the action is asked to perform after is not working. Is asked to change a button name literal on the view but it never happens. Otherwise with debugging the function seems tu run but there is no change on the view.
With Java are implemented the following classes:
public class Window extends JFrame {
JButton bGoFile;
public static final String FILE = "FILE";
public Window(ActionListener actionListener) {
this.actionListener = actionListener;
setupButtons();
setupView();
}
private void setupButtons() {
bGoFile = new JButton("Button");
bGoFile.addActionListener(actionListener);
bGoFile.setActionCommand(GO_FILE);
}
private void setupView() {
setTitle("Cover pdf to img");
setBounds(300, 90, 900, 600);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLocationRelativeTo(null);
setResizable(false);
setVisible(true);
ImageIcon icon = new ImageIcon("./src/resources/logo.jpg");
setIconImage(icon.getImage());
JPanel jp = new JPanel;
jp.add(bGoFile);
add(jp);
}
public void changeButtonName(String name) {
bGoFile.setText(name);
System.out.println("Name should be changed.");
// Here I already tried to user repaint() but with no result.
}
public class WindowController implements ActionListener {
Window window;
public WindowController() {
this.window = new Window(this);
}
#Override
public void actionPerformed(ActionEvent e) {
System.out.println("Action performed");
switch (e.getActionCommand()) {
case GO_FILE -> {
synchronized (this) {
window.changeButtonName("New name");
break;
}
}
}
}
The point is that the both prints on terminal are shown but the button name on the running Window is not changing.

You shouldn't be creating an instance of the view in the controller. This should be passed to the controller (AKA using dependency injection).
You should also be making use of interfaces, as the controller should not be bound to an implementation of a view (or model), but should be working through an established series of contracts and observers.
So, let's start with some basics...
public interface View {
public JComponent getView();
}
public interface Controller<V extends View> {
public V getView();
}
I did say basic. But, working with these interfaces directly will become tedious really fast, so let's add some helpers...
public abstract class AbstractController<V extends View> implements Controller<V> {
private V view;
public AbstractController(V view) {
this.view = view;
}
#Override
public V getView() {
return view;
}
}
public abstract class AbstractView extends JPanel implements View {
#Override
public JComponent getView() {
return this;
}
}
Nothing special, but this takes care of the a lot of boiler plating.
Next, we want to define the contract of our view...
public interface MainView extends View {
public interface Observer {
public void didPerformGoFile(MainView view);
}
public void addObserver(Observer observer);
public void removeObserver(Observer observer);
public void setDescription(String description);
}
That's pretty simple. Note though, this does not describe any kind of implementation detail. The contract does not care how didPerformGoFile might be generated, only that the action can be observed by interested parties
Next, we want to define or implementations for the MainView...
public class DefaultMainView extends AbstractView implements MainView {
private List<Observer> observers = new ArrayList<>(8);
private JButton goFileButton;
private JLabel descriptionLabel;
public DefaultMainView() {
goFileButton = new JButton("Make it so");
descriptionLabel = new JLabel("...");
descriptionLabel.setHorizontalAlignment(JLabel.CENTER);
setBorder(new EmptyBorder(32, 32, 32, 32));
setLayout(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridwidth = gbc.REMAINDER;
add(goFileButton, gbc);
add(descriptionLabel, gbc);
goFileButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
fireDidPerformGoFile();
}
});
}
#Override
public void addObserver(Observer observer) {
observers.add(observer);
}
#Override
public void removeObserver(Observer observer) {
observers.remove(observer);
}
protected void fireDidPerformGoFile() {
for (Observer observer : observers) {
observer.didPerformGoFile(this);
}
}
#Override
public void setDescription(String description) {
descriptionLabel.setText(description);
}
}
And MainController....
public class MainViewController extends AbstractController<MainView> {
public MainViewController(MainView view) {
super(view);
view.addObserver(new MainView.Observer() {
#Override
public void didPerformGoFile(MainView view) {
view.setDescription("Go file!");
}
});
}
}
Now, we can put them together and run them...
JFrame frame = new JFrame();
Controller controller = new MainViewController(new DefaultMainView());
frame.add(controller.getView().getView());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
Now, you're probably sitting there thinking, "that's a lot of work for little gain" and you'd be ... wrong, actually.
Let's say you wanted to change how the controller responds to the goFileAction depending on some kind of state, like the user's credentials or something. You could put a lot of logic into the MainViewController to handle it, or, more easily, just create a different controller altogether (nb: This is where the model in "Model-View-Controller" would come in, but since there's no concept of model in your example, I've done it "differently")
public class OverlordController extends AbstractController<MainView> {
public OverlordController(MainView view) {
super(view);
view.addObserver(new MainView.Observer() {
#Override
public void didPerformGoFile(MainView view) {
view.setDescription("Your overload has spoken!");
}
});
}
}
Then, by simply changing...
Controller controller = new MainViewController(new DefaultMainView());
to
Controller controller = new OverlordController(new DefaultMainView());
you change the output!
"Model-View-Controller" is not as straight forward in Swing as it might be in other APIs/frameworks, this is because Swing is already based on MVC, so you're actually wrapping a MVC on a MVC. If you understand this, you can make it work more easily.
For example, above, I don't expose the ActionListener to the controller, instead I created my own observer which described the actual actions which might be triggered by implementations of the view. The actual action handling took place in the implementation of the view itself.
This is good in the fact that we've decoupled the workflow, it also means that the view is free to implement the triggers for these actions in any way it sees fit.
You might want to also take a look at:
Implementing the Controller part of MVC in Java Swing
How MVC work with java swing GUI
Java and GUI - Where do ActionListeners belong according to MVC pattern?
What is the correct way of Message Passing between Classes in MVC?
Listener Placement Adhering to the Traditional (non-mediator) MVC Pattern
JTextField input fails to update output in TextView in MVC
Multithreaded MVC to recreate plane dashboard with multiple independent gauges
Where to store model objects in MVC design?
Runnable example...
import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;
public final class Main {
public static void main(String[] args) {
new Main();
}
public Main() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
JFrame frame = new JFrame();
Controller controller = new OverlordController(new DefaultMainView());
frame.add(controller.getView().getView());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public interface View {
public JComponent getView();
}
public interface Controller<V extends View> {
public V getView();
}
public abstract class AbstractController<V extends View> implements Controller<V> {
private V view;
public AbstractController(V view) {
this.view = view;
}
#Override
public V getView() {
return view;
}
}
public abstract class AbstractView extends JPanel implements View {
#Override
public JComponent getView() {
return this;
}
}
public interface MainView extends View {
public interface Observer {
public void didPerformGoFile(MainView view);
}
public void addObserver(Observer observer);
public void removeObserver(Observer observer);
public void setDescription(String description);
}
public class MainViewController extends AbstractController<MainView> {
public MainViewController(MainView view) {
super(view);
view.addObserver(new MainView.Observer() {
#Override
public void didPerformGoFile(MainView view) {
view.setDescription("Go file!");
}
});
}
}
public class OverlordController extends AbstractController<MainView> {
public OverlordController(MainView view) {
super(view);
view.addObserver(new MainView.Observer() {
#Override
public void didPerformGoFile(MainView view) {
view.setDescription("Your overload has spoken!");
}
});
}
}
public class DefaultMainView extends AbstractView implements MainView {
private List<Observer> observers = new ArrayList<>(8);
private JButton goFileButton;
private JLabel descriptionLabel;
public DefaultMainView() {
goFileButton = new JButton("Make it so");
descriptionLabel = new JLabel("...");
descriptionLabel.setHorizontalAlignment(JLabel.CENTER);
setBorder(new EmptyBorder(32, 32, 32, 32));
setLayout(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridwidth = gbc.REMAINDER;
add(goFileButton, gbc);
add(descriptionLabel, gbc);
goFileButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
fireDidPerformGoFile();
}
});
}
#Override
public void addObserver(Observer observer) {
observers.add(observer);
}
#Override
public void removeObserver(Observer observer) {
observers.remove(observer);
}
protected void fireDidPerformGoFile() {
for (Observer observer : observers) {
observer.didPerformGoFile(this);
}
}
#Override
public void setDescription(String description) {
descriptionLabel.setText(description);
}
}
}

How to change the icon of a dynamically generated JButton

I have this java swing program, and im trying to figure out how can i create a button that upon clicking it will clear the text areas & change the icon of the person to put their hand down.
The buttons are dynamically generated using a for loop
And this
// To create buttons
for(int i=0 ; i < list.length; i++){
Participant pa = list[i];
JButton b = new JButton(pa.getNameButton(),participant);
b.addActionListener(e ->
{
String s = pa.toString() + questionPane.getText();
final ImageIcon raise = resizeIcon(new ImageIcon("src/raise.png"),30,30);
b.setIcon(raise);
JOptionPane.showMessageDialog(null,s,"Welcome to Chat Room",JOptionPane.INFORMATION_MESSAGE,pa.getImage());
});
p.add(b);
}
// Clear button logic
clearButton.addActionListener(e ->{
questionPane.setText("");
hostPane.setText("");
});

Okay, this is going to be a bit of fun.
The following example decouples much of the concept and makes use of a basic "observer pattern" to notify interested parties that the state has changed (ie, the chat's been cleared).
This is a basic concept where by you decouple the "what" from the "how", ie, "what" it is you want done (update the model) from the "how" it gets done (ie, button push). This makes it easier to adapt to more complex systems.
The example contains a ChatService, which has a single listener, which, for this example, simple tells interested parties that the chat has been cleared.
A more complex solution might have the ChatService generating events for when a user "raises" their hand, which allows the interested parties to deal with it in what ever way is relevant to them.
The example makes use of the Action API to decouple the work performed by each action from the UI itself. This helps create a single unit of work which is easier to deal with when you have a dynamic data set.
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import javax.swing.AbstractAction;
import javax.swing.Action;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
JFrame frame = new JFrame();
frame.add(new TestPane());
frame.pack();
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
public TestPane() {
ChatService chatService = new ChatService();
JPanel panel = new JPanel();
String[] names = new String[] {"Bryan", "Alan", "George", "Henry"};
List<PeopleAction> actions = new ArrayList<>(names.length);
for (String name : names) {
PeopleAction action = new PeopleAction(chatService, name, false);
actions.add(action);
}
Random rnd = new Random();
actions.get(rnd.nextInt(names.length)).setRaised(true);
for (Action action : actions) {
JButton btn = new JButton(action);
panel.add(btn);
}
setLayout(new GridLayout(2, 1));
add(panel);
JPanel hostPane = new JPanel();
JButton clearButton = new JButton(new ClearAction(chatService));
hostPane.add(clearButton);
add(hostPane);
}
}
public class ChatService {
private List<ChatListener> listeners = new ArrayList<>(25);
public void addChatListeners(ChatListener listener) {
listeners.add(listener);
}
public void removeChatListener(ChatListener listener) {
listeners.remove(listener);
}
protected void fireChatCleared() {
if (listeners.isEmpty()) {
return;
}
for (ChatListener listener : listeners) {
listener.chatCleared();
}
}
public void clear() {
// Do what's required
fireChatCleared();
}
}
public interface ChatListener {
public void chatCleared();
}
public class PeopleAction extends AbstractAction implements ChatListener {
private String name;
private boolean raised;
public PeopleAction(ChatService chatService, String name, boolean raised) {
// You can use either LARGE_ICON_KEY or SMALL_ICON to set the icon
this.name = name;
if (raised) {
putValue(NAME, "* " + name);
} else {
putValue(NAME, name);
}
chatService.addChatListeners(this);
}
public void setRaised(boolean raised) {
if (raised) {
putValue(NAME, "* " + name);
} else {
putValue(NAME, name);
}
}
public boolean isRaised() {
return raised;
}
#Override
public void actionPerformed(ActionEvent evt) {
// Do what ever needs to be done
setRaised(!isRaised());
}
#Override
public void chatCleared() {
setRaised(false);
}
}
public class ClearAction extends AbstractAction {
private ChatService chatService;
public ClearAction(ChatService chatService) {
this.chatService = chatService;
putValue(NAME, "Clear");
}
#Override
public void actionPerformed(ActionEvent evt) {
chatService.clear();
}
}
}

Java Observer/Observable update

I've tried to apply the Observable/Observer pattern but there is something wrong with my code when I try to change a the textfield of a JTextPane.
I've got 3 classes, Play, Controller and SecondWindow here are a sample of their code.
public class Play() {
Controller c = new Controller();
SecondWindow sw = new SecondWindow();
c.addObserver(sw)
c.setText("blabla");
}
My class Controller:
public class Controller extends Observable(){
private String text ="";
private static Controller getInstance() {
if (instance == null) {
instance = new Controller();
}
return instance;
}
public void setText(String s) {
text = s;
setChanged();
notifyObservers();
}
}
and SecondWindow:
public class SecondWindow extends JFrame implements Observer{
private JPanel contentPane;
private Controller c;
private JTextPane txt = new JTextPane();
public SecondWindow () {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
SecondWindow frame = new SecondWindow();
frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
public SecondWindow() {
initComponents();
createEvents();
c = Controller.getInstance();
}
public void initComponents() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setBounds(1000, 0, 300,500);
contentPane = new JPanel();
contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
setContentPane(contentPane);
contentPane.setLayout(null);
txt.setBounds(0, 0, 280, 460);
txt.enable(false);
contentPane.add(txt);
}
public void update(Observable arg0 , Object arg1){
// Things to change here
}
I can't manage to put the variable c in the textField (like a txt.setText(c.getText) instruction). I'm sure that it reads the method update, but I don't know how to make sure it works.

Hint: Per the Observerable API the notifyObservers method has an overload that accepts any object as a parameter:
public void notifyObservers(Object arg)
This can even be a String. And as per the Observer API, this object is then passed into the update method in the observer, and you can use it there.
void update(Observable o,
Object arg)
arg - an argument passed to the notifyObservers method.
Separate side issue here:
contentPane.setLayout(null);
For most Swing aficionados, seeing this is like hearing nails on a chalkboard -- it's painful. While null layouts and setBounds() might seem to Swing newbies like the easiest and best way to create complex GUI's, the more Swing GUI'S you create the more serious difficulties you will run into when using them. They won't resize your components when the GUI resizes, they are a royal witch to enhance or maintain, they fail completely when placed in scrollpanes, they look gawd-awful when viewed on all platforms or screen resolutions that are different from the original one. Instead you will want to study and learn the layout managers and then nest JPanels, each using its own layout manager to create pleasing and complex GUI's that look good on all OS's.
Side issue number two: your code is not Swing thread safe, since the Swing GUI could very well be notified by the observable off of the Swing event dispatch thread or EDT. While it is not likely to cause frequent or serious problems with this simple program, in general it would be better to use a SwingPropertyChangeSupport and PropertyChangeListeners rather than Observer / Observable if you can.
Next Side Issue
This:
public class Controller extends Observable(){
isn't compilable / kosher Java. Same for the duplicate parameter-less constructors for the SecondWindow class. Yes, we know what you're trying to do, but it's hard enough trying to understand someone else's code, you really don't want to make it harder by posting kind-of sort-of uncompilable code, trust me.
For example, something simple could be implemented in Swing using PropertyChangeListeners, like so:
import java.util.concurrent.TimeUnit;
public class Play2 {
public static void main(String[] args) {
Model2 model2 = new Model2();
View2 view2 = new View2();
new Controller2(model2, view2);
view2.show();
for (int i = 0; i < 10; i++) {
try {
TimeUnit.SECONDS.sleep(1);
} catch (InterruptedException e) {
// one of the few times it's OK to ignore an exception
}
String text = String.format("Counter Value: %d", i);
model2.setText(text);
}
}
}
import java.beans.PropertyChangeListener;
import javax.swing.event.SwingPropertyChangeSupport;
public class Model2 {
private SwingPropertyChangeSupport pcSupport = new SwingPropertyChangeSupport(this);
public static final String TEXT = "text"; // name of our "bound" property
private String text = "";
public String getText() {
return text;
}
public void setText(String text) {
String oldValue = this.text;
String newValue = text;
this.text = text;
pcSupport.firePropertyChange(TEXT, oldValue, newValue);
}
public void addPropertyChangeListener(PropertyChangeListener listener) {
pcSupport.addPropertyChangeListener(listener);
}
public void removePropertyChangeListener(PropertyChangeListener listener) {
pcSupport.removePropertyChangeListener(listener);
}
public void addPropertyChangeListener(String name, PropertyChangeListener listener) {
pcSupport.addPropertyChangeListener(name, listener);
}
public void removePropertyChangeListener(String name, PropertyChangeListener listener) {
pcSupport.removePropertyChangeListener(name, listener);
}
}
import javax.swing.*;
public class View2 {
private JPanel mainPanel = new JPanel();
private JTextField textField = new JTextField(10);
public View2() {
textField.setFocusable(false);
mainPanel.add(new JLabel("Text:"));
mainPanel.add(textField);
}
public JPanel getMainPanel() {
return mainPanel;
}
public void setText(String text) {
textField.setText(text);
}
public void show() {
SwingUtilities.invokeLater(() -> {
JFrame frame = new JFrame("View");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(getMainPanel());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
});
}
}
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
public class Controller2 {
private Model2 model2;
private View2 view2;
public Controller2(Model2 model2, View2 view2) {
this.model2 = model2;
this.view2 = view2;
model2.addPropertyChangeListener(Model2.TEXT, new ModelListener());
}
private class ModelListener implements PropertyChangeListener {
#Override
public void propertyChange(PropertyChangeEvent pcEvt) {
view2.setText((String) pcEvt.getNewValue());
}
}
}

How to set selected index JComboBox by value

I want to set the selected index in a JComboBox by the value not the index. How to do that? Example
public class ComboItem {
private String value;
private String label;
public ComboItem(String value, String label) {
this.value = value;
this.label = label;
}
public String getValue() {
return this.value;
}
public String getLabel() {
return this.label;
}
#Override
public String toString() {
return label;
}
}
JComboBox test = new JComboBox();
test.addItem(new ComboItem(0, "orange"));
test.addItem(new ComboItem(1, "pear"));
test.addItem(new ComboItem(2, "apple"));
test.addItem(new ComboItem(3, "banana"));
test.setSelectedItem("banana");
Ok, I have modified my question a bit. I forgot that i have a custom item inside my JComboBox that makes it a bit more difficult. i cant do setSelectedItem as i have a ComboItem inside each item. So still, how do i get this done?

setSelectedItem("banana"). You could have found it yourself by just reading the javadoc.
Edit: since you changed the question, I'll change my answer.
If you want to select the item having the "banana" label, then you have two solutions:
Iterate through the items to find the one (or the index of the one) which has the given label, and then call setSelectedItem(theFoundItem) (or setSelectedIndex(theFoundIndex))
Override equals and hashCode in ComboItem so that two ComboItem instances having the same name are equal, and simply use setSelectedItem(new ComboItem(anyNumber, "banana"));

You should use model
comboBox.getModel().setSelectedItem(object);

public static void setSelectedValue(JComboBox comboBox, int value)
{
ComboItem item;
for (int i = 0; i < comboBox.getItemCount(); i++)
{
item = (ComboItem)comboBox.getItemAt(i);
if (item.getValue().equalsIgnoreCase(value))
{
comboBox.setSelectedIndex(i);
break;
}
}
}
Hope this help :)

Why not take a collection, likely a Map such as a HashMap, and use it as the nucleus of your own combo box model class that implements the ComboBoxModel interface? Then you could access your combo box's items easily via their key Strings rather than ints.
For instance...
import java.util.HashMap;
import java.util.Map;
import javax.swing.ComboBoxModel;
import javax.swing.event.ListDataListener;
public class MyComboModel<K, V> implements ComboBoxModel {
private Map<K, V> nucleus = new HashMap<K, V>();
// ... any constructors that you want would go here
public void put(K key, V value) {
nucleus.put(key, value);
}
public V get(K key) {
return nucleus.get(key);
}
#Override
public void addListDataListener(ListDataListener arg0) {
// TODO Auto-generated method stub
}
// ... plus all the other methods required by the interface
}

for example
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.SwingUtilities;
public class ComboboxExample {
private JFrame frame = new JFrame("Test");
private JComboBox comboBox = new JComboBox();
public ComboboxExample() {
createGui();
}
private void createGui() {
comboBox.addItem("One");
comboBox.addItem("Two");
comboBox.addItem("Three");
JButton button = new JButton("Show Selected");
button.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
JOptionPane.showMessageDialog(frame, "Selected item: " + comboBox.getSelectedItem());
javax.swing.SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
comboBox.requestFocus();
comboBox.requestFocusInWindow();
}
});
}
});
JButton button1 = new JButton("Append Items");
button1.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
appendCbItem();
}
});
JButton button2 = new JButton("Reduce Items");
button2.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
reduceCbItem();
}
});
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new GridLayout(4, 1));
frame.add(comboBox);
frame.add(button);
frame.add(button1);
frame.add(button2);
frame.setLocation(200, 200);
frame.pack();
frame.setVisible(true);
selectFirstItem();
}
public void appendCbItem() {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
comboBox.addItem("Four");
comboBox.addItem("Five");
comboBox.addItem("Six");
comboBox.setSelectedItem("Six");
requestCbFocus();
}
});
}
public void reduceCbItem() {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
comboBox.removeItem("Four");
comboBox.removeItem("Five");
comboBox.removeItem("Six");
selectFirstItem();
}
});
}
public void selectFirstItem() {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
comboBox.setSelectedIndex(0);
requestCbFocus();
}
});
}
public void requestCbFocus() {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
comboBox.requestFocus();
comboBox.requestFocusInWindow();
}
});
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
ComboboxExample comboboxExample = new ComboboxExample();
}
});
}
}

http://docs.oracle.com/javase/6/docs/api/javax/swing/JComboBox.html#setSelectedItem(java.lang.Object)
test.setSelectedItem("banana");
There are some caveats or potentially unexpected behavior as explained in the javadoc. Make sure to read that.

The right way to set an item selected when the combobox is populated by some class' constructor (as #milosz posted):
combobox.getModel().setSelectedItem(new ClassName(parameter1, parameter2));
In your case the code would be:
test.getModel().setSelectedItem(new ComboItem(3, "banana"));

Just call comboBox.updateUI() after doing comboBox.setSelectedItem or comboBox.setSelectedIndex or comboModel.setSelectedItem

public boolean preencherjTextCombox (){
int x = Integer.parseInt(TableModelo.getModel().getValueAt(TableModelo.getSelectedRow(),0).toString());
modeloobj = modelosDAO.pesquisar(x);
Combmarcass.getModel().setSelectedItem(modeloobj.getMarca());
txtCodigo.setText(String.valueOf(modeloobj.getCodigo()));
txtDescricao.setText(String.valueOf(modeloobj.getDescricao()));
txtPotencia.setText(String.valueOf(modeloobj.getPotencia()));
return true;
}

In my case build class Item(key, value) as item of combobox
SanPhamDTO currentProd = prodDao.getDetailById(id);
Item item = new Item(currentProd.getCategory().getId(),
currentProd.getCategory().getName());
cbdanhmuc.getModel().setSelectedItem(item)

Java MVC - How to divide a done text game into MVC?

Been sitting here for hours now trying to figure this out, so a bit sympathy for this large question. :)
The Goal: I simply want to divide my done code into MVC (Model View Controller) parts. I have the game logics done and text based - the code works fine.
The Problem: Well, I want to implement this code into MVC, but where do explain for the MODEL that it should use text-based? Because the VIEW is only for the layout (graphically) correct? I am having a REALLY hard time figuring out where to begin at all. Any pointers would be so nice!
Here is my game logics code:
import mind.*;
import javax.swing.*;
import java.util.*;
import java.lang.*;
import java.awt.*;
public class Drive {
String[] mellan;
boolean gameEnd, checkempty, checkempty2, enemy, enemy2;
String gr,rd,tom;
int digits;
public Drive() {
// Gamepieces in textform
gr="G"; rd="R"; tom=" ";
mellan = new String[7];
String[] begin = {gr,gr,gr,tom,rd,rd,rd};
String[] end = {rd,rd,rd,tom,gr,gr,gr};
//input
Scanner in = new Scanner(System.in);
mellan=begin;
gameEnd=false;
while (gameEnd == false) {
for(int i=0; i<mellan.length; i++) {
System.out.print(mellan[i]);
}
System.out.print(" Choose 0-6: ");
digits = in.nextInt();
move();
checkWin();
}
}
void move() {
//BOOLEAN for gameruls!!!
checkempty = digits<6 && mellan[digits+1]==tom;
checkempty2 = digits>0 && mellan[digits-1]==tom;
enemy = (mellan[digits]==gr && mellan[digits+1]==rd && mellan[digits+2]==tom);
enemy2 = (mellan[digits]==rd && mellan[digits-1]==gr && mellan[digits-2]==tom);
if(checkempty) {
mellan[digits+1]=mellan[digits];
mellan[digits]=tom;
} else if (checkempty2) {
mellan[digits-1]=mellan[digits];
mellan[digits]=tom;
} else if (enemy) {
mellan[digits+2]=mellan[digits];
mellan[digits]=tom;
} else if (enemy2) {
mellan[digits-2]=mellan[digits];
mellan[digits]=tom;
}
}
void checkWin() {
String[] end = {rd,rd,rd,tom,gr,gr,gr};
for (int i=0; i<mellan.length; i++){
}
if (Arrays.equals(mellan,end)) {
for (int j=0; j<mellan.length; j++) {
System.out.print(mellan[j]);
}
displayWin();
}
}
void displayWin() {
gameEnd = true;
System.out.println("\nNicely Done!");
return;
}
// Kör Drive!
public static void main(String args[]) {
new Drive();
}
}
Here is how I defined my DriveView thus far: (just trying to make one button to work)
import mind.*;
import javax.swing.*;
import java.util.*;
import java.lang.*;
import java.awt.*;
import java.awt.event.*;
public class DriveView extends JFrame {
JButton ruta1 = new JButton("Green");
JButton ruta2 = new JButton("Green");
JButton rutatom = new JButton("");
JButton ruta6 = new JButton("Red");
private DriveModel m_model;
public DriveView(DriveModel model) {
m_model = model;
//Layout for View
JPanel myPanel = new JPanel();
myPanel.setLayout(new FlowLayout());
myPanel.add(ruta1);
myPanel.add(ruta2);
myPanel.add(rutatom);
myPanel.add(ruta6);
this.setContentPane(myPanel);
this.pack();
this.setTitle("Drive");
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
void addMouseListener(ActionListener mol) {
ruta2.addActionListener(mol);
}
}
And DriveController which gives me error at compile
import mind.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.lang.*;
public class DriveController {
private DriveModel m_model;
private DriveView m_view;
public DriveController(DriveModel model, DriveView view) {
m_model = model;
m_view = view;
view.addMouseListener(new MouseListener());
}
class MouseListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
String mening;
mening = e.getActionCommand();
if (mening.equals("Green")) {
setForeground(Color.red);
}
}
}
}

Your game model can have more than one view: a GUI view, a console view, a status view, etc. Typically each view arranges to listen for changes in the model, and it then queries the model for the information it needs to render it's particular view. This simple game was designed specifically to illustrate the concepts. The section named "Design" elaborates in more detail.
Addendum: This outline corresponds roughly to this architecture, symbolized below.
public class MVCOutline {
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
//#Override
public void run() {
new MVCOutline().create();
}
});
}
private void create() {
JFrame f = new JFrame("MVC Outline");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(new MainPanel());
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
}
}
class MainPanel extends JPanel {
public MainPanel() {
super(new BorderLayout());
Model model = new Model();
View view = new View(model);
Control control = new Control(model, view);
this.add(view, BorderLayout.CENTER);
this.add(control, BorderLayout.WEST);
}
}
class Control extends JPanel implements ... {
private Model model;
private View view;
public Control(Model model, View view) {
this.model = model;
this.view = view;
}
}
class View extends JPanel implements Observer {
private Model model;
public View(Model model) {
this.model = model;
model.addObserver(this);
}
public void update(Observable o, Object arg) {
// update GUI based on model
}
}
class Model extends Observable {
public void next() {
this.notifyObservers(...);
}
}

To take a stab (and this is kind of overkill), I would make a game state bean that would represent the state that the game is currently in; that would be a "model object". Looking at your code, it would probably contain String [] mellan. Then I would have a data access object that contains a reference to the game state bean and it would have methods for updating the game state.
The game logic for different actions would be in a service object that has a reference to the data access object and the controller would have a reference to the service object. It would call the different action methods depending on what interaction was received from the interface, the view.
Like I said, this is kind of overkill.