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JPanel of main does not get updated from another class

I have class Home that extends JFrame, it holds a static variable panel_event. I have another class called EventLabel, which created a label and it's functions and adds it to the panel using refresh() method, code runs with no error, but my panel_event content does not get updated "show"
I have already added revalidate(), and repaint() methods
public EventLabel(String name2, String date2, int priority2, String note2) {
super();
this.name = name2;
this.date = date2;
this.priority = priority2;
this.note = note2;
}
public void buildLabel() {
label = new JLabel(this.getName());
label.setBounds(10, 11, 403, 34);
label.setForeground(Color.WHITE);
label.setFont(new Font("Yu Gothic UI Light", Font.PLAIN, 20));
String n = this.getNote();
String d = this.getDate();
int p = this.getPriority();
String na = this.getName();
setFont(new Font("Yu Gothic UI Light", Font.PLAIN, 20));
label.addMouseListener(new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent e) {
EventDetailFrame detailFrame = new EventDetailFrame();
detailFrame.NewWindow();
detailFrame.textAreaNoteD.setText(n);
detailFrame.textFieldNameD.setText(na);
detailFrame.textFieldDateD.setText(d);
detailFrame.textFieldPriorityD.setText("Priority");
}
});
}
public void refresh(){
panel_event.add(label);
panel_event.revalidate();
panel_event.repaint();
}
This is the frame with button that is suppose to change content of panel_event
btnSaveAndClose.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
String name = txtEventName.getText();
String date = txtEventDate.getText();
String note = txtEventNote.getText();
int priority = getPriorityNumber(txtEventPriority.getText());
Event event = new Event(name, date, note, priority);
EventLabel event_label = new EventLabel(event.getName(),event.getDate(),event.getPriority(),event.getNote());
event_label.buildLabel();
event_label.refresh();
dispose();
}
});
After clicking btnSaveAndClose, I expected the panel_event to show my new JLabel

I created a working example on how to show new label. You can call validate() and repaint().
import java.awt.Color;
import java.awt.Font;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.StringJoiner;
import javax.swing.BorderFactory;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
public class EventLabel extends JLabel
{
private static final long serialVersionUID = -3122247523298894551L;
public EventLabel(String name, String date, String priority, String note)
{
super(name);
setBorder(BorderFactory.createLineBorder(Color.WHITE, 3, false));
setFont(new Font("Yu Gothic UI Light", Font.PLAIN, 20));
this.setOpaque(true);
setBackground(Color.WHITE);
addMouseListener(new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent e)
{
StringJoiner text = new StringJoiner("\n");
text.add("name: " + name);
text.add("date: " + date);
text.add("priority: " + priority);
text.add("note: " + note);
JOptionPane.showMessageDialog(null, text, "Event", JOptionPane.INFORMATION_MESSAGE);
}
});
}
}
AND
import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.GridLayout;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
public class Main
{
private static JButton button;
private static JPanel labelPanel;
private static JTextField nameField;
private static JTextField dateField;
private static JTextField priorityField;
private static JTextField noteField;
public static void main(String[] args)
{
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run()
{
JFrame window = new JFrame();
window.setResizable(false);
window.setTitle("Label Test");
window.getContentPane().add(getContent());
initController();
window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
window.setSize(680, 700);
window.setLocationRelativeTo(null);
window.setVisible(true);
}
});
}
protected static void initController()
{
button.addActionListener(event -> {
labelPanel.add(new EventLabel(nameField.getText(), dateField.getText(), priorityField.getText(),
noteField.getText()));
nameField.setText("");
dateField.setText("");
priorityField.setText("");
noteField.setText("");
labelPanel.validate();
labelPanel.repaint();
});
}
private static Component getContent()
{
JPanel panel = new JPanel(new BorderLayout());
panel.add(getNorthPanel(), BorderLayout.NORTH);
labelPanel = new JPanel(new FlowLayout());
labelPanel.setBorder(BorderFactory.createTitledBorder("Events"));
panel.add(labelPanel, BorderLayout.CENTER);
return panel;
}
private static Component getNorthPanel()
{
JPanel panel = new JPanel(new FlowLayout());
JPanel inputPanel = new JPanel(new GridLayout(0, 2));
inputPanel.setPreferredSize(new Dimension(400, 100));
nameField = new JTextField();
dateField = new JTextField();
priorityField = new JTextField();
noteField = new JTextField();
inputPanel.add(new JLabel("name"));
inputPanel.add(nameField);
inputPanel.add(new JLabel("date"));
inputPanel.add(dateField);
inputPanel.add(new JLabel("priority"));
inputPanel.add(priorityField);
inputPanel.add(new JLabel("note"));
inputPanel.add(noteField);
panel.add(inputPanel);
button = new JButton("add event");
panel.add(button);
return panel;
}
}

Can I use actionListeners on JPanels?

I am trying to add and actionListener to a JPanel it's self but keep getting the error"cannot find symbol". I was just wondering if it is possible to do this as I want to be able to click on the panel and make the colour change. Any help would be appreciated.
Here is what i have so far.
import java.awt.*;
import javax.swing.*;
import javax.swing.JPanel.*;
import java.awt.Color.*;
import java.awt.event.*;
/**
* Write a description of class SimpleFrame here.
*
* #author OFJ2
* #version
*/
public class Game extends JFrame
implements ActionListener
{
private final int ROWS = 5;
private final int COLUMS = 2;
private final int GAP = 2;
private final int SIZE = ROWS * COLUMS;
private int x;
private JPanel leftPanel = new JPanel(new GridLayout(ROWS,COLUMS, GAP,GAP));
private JPanel [] gridPanel = new JPanel[SIZE];
private JPanel middlePanel = new JPanel();
private JPanel rightPanel = new JPanel();
private Color col1 = Color.GREEN;
private Color col2 = Color.YELLOW;
private Color tempColor;
public Game()
{
super("Chasing Bombs OFJ2");
setSize(200,200);
setVisible(true);
makeFrame();
}
public void makeFrame()
{
Container contentPane = getContentPane();
contentPane.setLayout(new GridLayout());
leftPanel.setLayout(new GridLayout(ROWS, COLUMS));
//JLabel label2 = new JLabel("Pocahontas");
JButton playButton = new JButton("Play Game");
JButton exitButton = new JButton("Exit");
JButton easyButton = new JButton("Easy");
JButton mediumButton = new JButton("Medium");
JButton hardButton = new JButton("Hard");
add(leftPanel);
add(middlePanel, new FlowLayout());
add(rightPanel);
setGrid();
middlePanel.add(playButton);
middlePanel.add(exitButton);
rightPanel.add(easyButton);
rightPanel.add(mediumButton);
rightPanel.add(hardButton);
leftPanel.setBackground(Color.PINK);
middlePanel.setBackground(Color.RED);
easyButton.addActionListener(this);
mediumButton.addActionListener(this);
hardButton.addActionListener(this);
playButton.addActionListener(this);
exitButton.addActionListener(this);
}
public void setGrid()
{
for(int x = 0; x < SIZE; x++) {
gridPanel[x] = new JPanel();
gridPanel[x].setBorder(BorderFactory.createLineBorder(Color.BLACK));
leftPanel.add(gridPanel[x]);
gridPanel[x].setBackground(Color.GREEN);
gridPanel[x].addActionListener(this);
}
}
#Override
public void actionPerformed(ActionEvent e)
{
Object source = e.getSource();
if (source == gridPanel[0]){
gridPanel[x].setBackground(Color.BLACK);
}
}
}
I have tried to find if there is any other method that is needed to do this but cant find anything. Is it possible that I will have to add a button to fill each of the panels to make this work?
Thanks!

It defaults to no addActionListener, and the code below is a reference suggestion.
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.ArrayList;
import java.util.List;
class GPanel extends JPanel {
private List<ActionListener> listenerList = new ArrayList<>();
public GPanel() {
addMouseListener(new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent e) {
var event = new ActionEvent(this, ActionEvent.ACTION_PERFORMED, "GPanel");
for (var i : listenerList) {
i.actionPerformed(event);
}
}
});
}
public void addActionListener(ActionListener listener) {
listenerList.add(listener);
}
}
public class ActionListenerTest extends JFrame {
public static void main(String[] args) {
new ActionListenerTest();
}
public ActionListenerTest() {
GPanel test = new GPanel();
test.setBackground(Color.BLUE);
add(test);
test.addActionListener(e-> {
System.out.println("Click: " + e.getActionCommand());
});
pack();
setDefaultCloseOperation(EXIT_ON_CLOSE);
setVisible(true);
}
}

Get the selected component from a JPanel

I am dynamically adding items to my JPanel through an ArrayList<Items>. Basically the items object looks like that:
public class Item {
private JComponent component;
private String functionality;
public Item(JComponent component, String functionality) {
super();
this.component = component;
this.functionality = functionality;
}
public JComponent getComponent() {
return component;
}
public void setComponent(JComponent component) {
this.component = component;
}
public String getFunctionality() {
return functionality;
}
public void setFunctionality(String functionality) {
this.functionality = functionality;
}
}
Here I am adding my buttons dynamically: (try the example out if you want)
public class minimumExample extends JFrame {
private JButton addItem;
private JComboBox itemBox;
private String[] itemSelect = { "test1", "test2" };
private JPanel addUpperPane;
private JPanel addLowerPane;
private ArrayList<Item> displayedItems = new ArrayList<Item>();
private JButton upButton;
private JButton downButton;
private JButton deleteButton;
public void createControlPane() {
addUpperPane = new JPanel();
addLowerPane = new JPanel(new GridLayout(0, 1));
addItem = new JButton("Add item");
upButton = new JButton("Up");
downButton = new JButton("Down");
deleteButton = new JButton("Delete");
itemBox = new JComboBox(itemSelect);
addItem.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
if(itemBox.getSelectedItem().toString().equals("test1")) {
displayedItems.add(new Item( new ButtonComp().butt(), "test1"));
validate();
repaint();
}
if(itemBox.getSelectedItem().toString().equals("test2")) {
displayedItems.add(new Item( new LabelComp().label(), "test2"));
validate();
repaint();
}
for (int i = 0; i < displayedItems.size(); i++) {
addLowerPane.add(displayedItems.get(i).getComponent());
validate();
repaint();
}
}
});
addUpperPane.add(itemBox, BorderLayout.EAST);
addUpperPane.add(addItem, BorderLayout.WEST);
addUpperPane.add(new JLabel(" | "), BorderLayout.WEST);
addUpperPane.add(upButton, BorderLayout.WEST);
addUpperPane.add(downButton, BorderLayout.WEST);
addUpperPane.add(deleteButton, BorderLayout.WEST);
addUpperPane.add(new JSeparator(JSeparator.HORIZONTAL));
//put everything together
add(addUpperPane, BorderLayout.NORTH);
add(addLowerPane, BorderLayout.SOUTH);
repaint();
}
private void makeLayout() {
setTitle("Test App");
setLayout(new BorderLayout());
setPreferredSize(new Dimension(1000, 500));
createControlPane();
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
pack();
setVisible(true);
}
/**
* starts the GUI
*/
public void start() {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
makeLayout();
}
});
}
public static void main(String[] args) throws IOException {
minimumExample ex = new minimumExample();
ex.start();
}
public class ButtonComp extends Component {
public JPanel butt() {
JPanel panel = new JPanel();
JButton button = new JButton("Test1");
JCheckBox check = new JCheckBox();
panel.add(button);
panel.add(check);
return panel;
}
}
public class LabelComp extends Component {
public JPanel label() {
JPanel panel = new JPanel();
JLabel label = new JLabel("Test2");
JCheckBox check = new JCheckBox();
panel.add(label);
panel.add(check);
return panel;
}
}
}
The program basically looks like that:
My problem is that the buttons Up, Down and Delete do not work, because I do not know how to get the selected element from the pane to delete it from the list where all components are in. Any recommendations on how to make this work?
I really appreciate your answer!
UPDATE
I changed my code your specifications #cghislai but it does not work. Try it out yourself:
import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JSeparator;
public class minimumExample extends JFrame {
private JButton addItem;
private JComboBox itemBox;
private String[] itemSelect = { "test1", "test2" };
private JPanel addUpperPane;
private JPanel addLowerPane;
private List<CheckableItem> displayedItems = new ArrayList<CheckableItem>();
private JButton upButton;
private JButton downButton;
private JButton deleteButton;
public void createControlPane() {
addUpperPane = new JPanel();
addLowerPane = new JPanel(new GridLayout(0, 1));
addItem = new JButton("Add item");
upButton = new JButton("Up");
downButton = new JButton("Down");
deleteButton = new JButton("Delete");
itemBox = new JComboBox(itemSelect);
addItem.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
if(itemBox.getSelectedItem().toString().equals("test1")) {
ButtonComp butt = new ButtonComp();
butt.init();
displayedItems.add(butt);
validate();
repaint();
}
if(itemBox.getSelectedItem().toString().equals("test2")) {
// displayedItems.add(new CopyOfItem( new LabelComp(), "test2"));
validate();
repaint();
}
for (int i = 0; i < displayedItems.size(); i++) {
addLowerPane.add(displayedItems.get(i).getComponent());
validate();
repaint();
}
}
});
deleteButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent arg0) {
Iterator<CheckableItem> it = displayedItems.iterator();
while (it.hasNext()) {
CheckableItem next = it.next();
if (next.isSelected()) {
addLowerPane.remove(next.getComponent());
it.remove();
continue;
}
}
}
});
addUpperPane.add(itemBox, BorderLayout.EAST);
addUpperPane.add(addItem, BorderLayout.WEST);
addUpperPane.add(new JLabel(" | "), BorderLayout.WEST);
addUpperPane.add(upButton, BorderLayout.WEST);
addUpperPane.add(downButton, BorderLayout.WEST);
addUpperPane.add(deleteButton, BorderLayout.WEST);
addUpperPane.add(new JSeparator(JSeparator.HORIZONTAL));
//put everything together
add(addUpperPane, BorderLayout.NORTH);
add(addLowerPane, BorderLayout.SOUTH);
repaint();
}
private void makeLayout() {
setTitle("Test App");
setLayout(new BorderLayout());
setPreferredSize(new Dimension(1000, 500));
createControlPane();
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
pack();
setVisible(true);
}
/**
* starts the GUI
*/
public void start() {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
makeLayout();
}
});
}
public static void main(String[] args) throws IOException {
minimumExample ex = new minimumExample();
ex.start();
}
public abstract class CheckableItem {
protected JCheckBox check;
public boolean isSelected() {
return check.isSelected();
}
public abstract Component getComponent();
}
public class ButtonComp extends CheckableItem {
JPanel panel = new JPanel();
public void init() {
JButton button = new JButton("Test1");
check = new JCheckBox();
panel.add(button);
panel.add(check);
}
#Override
public Component getComponent() {
return panel;
}
}
public class LabelComp extends JPanel {
public void label() {
// JPanel panel = new JPanel();
JLabel label = new JLabel("Test2");
JCheckBox check = new JCheckBox();
add(label);
add(check);
}
}
}

You need to traverse all your items, check if the item checkbox is selected, if this is the case, remove your item from the panel. I would make an abstract CheckableItem class with a getter to the JCheckbox and the Component. Then, for each of you item, if the checkbox is selected, remove the component from the parent.
public abstract class CheckableItem {
protected JCheckbox checkbox;
public boolean isSelected() {
return checkbox.isSelected();
}
public abstract Component getComponent();
}
public class ButtonComp extends CheckableItem {
private Panel panel;
public void init() {
checkbox = new JCheckbox;
panel = new JPanel();
panel.add(new JButton());
panel.add(checkbox);
}
public Component getComponent() {
return panel;
}
}
Then to keep track of your items:
private List<CheckableItem> items = new ArrayList<>();
// ...
ButtonComp comp = new ButtonComp();
comp.init();
items.add(comp);
Then to remove all checked:
Iterator<CheckbleItem> it = items.iterator();
while (it.hasNext()) {
CheckableItem next = it.next();
if (next.isSelected()) {
mainPanel.remove(next.getComponent());
it.remove();
continue;
}
}

Why don't you just have your ButtomComp and LabelComp extend from JPanel? This would solve a lot of your problems I think. For example :
public class ButtonComp extends JPanel {
JButton button;
JCheckBox check = new JCheckBox();
public ButtonComp() {
button = new JButton("Test1");
this.add(button);
this.add(check);
}
}
Then all you would need to do is iterate over your items and look at the checkbox in the components :
for (int i = 0; i < displayedItems.size(); i++) {
if (displayedItems.get(i).check.isSelected()) {
displayedItems.remove(i);
}
}
Note: haven't tested this code. But you should get the idea.

Singleton with CardLayout won't show card when another class calls Singleton.instance.show()

public class MainWindow extends JPanel {
public static MainWindow instance = new MainWindow();
private CardLayout cards = new CardLayout();
public MainWindow() {
setLayout(cards);
add(new FirstPage(), Pages.FIRST.toString());
add(new SecondPage(), Pages.SECOND.toString());
add(new ThirdPage(), Pages.THIRD.toString());
}
public void showPage(Pages page) {
cards.show(this, page.toString());
}
}
the showPage(page); method works fine if I call it in the constructor of MainWindow. But when I try to call MainWindow.instance.showPage(Pages.SECOND); from an ActionListener in FirstPage nothing happens. I've checked that the showPage(page) method works correctly. I've checked that the ActionEvent is fired and enters the correct if/else clause. What am I doing wrong, why isn't my second page showing?
public class FirstPage extends JPanel {
private JButton showSecond = new JButton("Show Second");
private JButton showThird = new JButton("Show Third");
public FirstPage() {
insertButton(showSecond);
insertButton(showThird);
}
private void insertButton(JButton button) {
button.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
if (e.getSource() == showSecond) {
MainWindow.instance.showPage(Pages.SECOND);
} else {
MainWindow.instance.showPage(Pages.THIRD);
}
}
});
this.add(button);
}
}

It would suggest a reference issue. public static MainWindow instance = new MainWindow(); looks suspicious, as you would have had to create an instance of MainWindow first for it to be initialise which suggests you now have two instances of MainWindow, one on the screen and one that is not
Using static in this way is a bad idea, as it leads to issues like this. Instead you should pass a reference of the controller to the page. The controller would define the actions that each page could perform (and if done right, would be defined as an interface)
Alternatively, you could separate the navigation from the pages into a separate mechanism, this means the pages don't care and can simply displayed in any order you want or reused else where
Example #1 - Controller based pages
This examples defines a simple controller which the pages can call in order to effect the navigation of the pages
import java.awt.BorderLayout;
import java.awt.CardLayout;
import java.awt.EventQueue;
import java.awt.FlowLayout;
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.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class CardLayoutExample {
public static void main(String[] args) {
new CardLayoutExample();
}
public CardLayoutExample() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new Wizard());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public interface NavigationController {
public void nextPage();
public void previousPage();
public void lastPage();
public void firstPage();
}
public interface Page {
public NavigationController getNavigationController();
public JComponent getView();
public String getName();
}
public class Wizard extends JPanel implements NavigationController {
private List<Page> pages;
private Page currentPage;
private CardLayout cardLayout;
public Wizard() {
cardLayout = new CardLayout();
pages = new ArrayList<>(25);
setLayout(cardLayout);
pages.add(new FirstPage("Page01", this));
pages.add(new SecondPage("Page02", this));
pages.add(new ThirdPage("Page03", this));
for (Page page : pages) {
add(page.getView(), page.getName());
}
firstPage();
}
#Override
public void nextPage() {
int index = pages.indexOf(currentPage);
index++;
if (index < pages.size()) {
cardLayout.next(this);
currentPage = pages.get(index);
}
}
#Override
public void previousPage() {
int index = pages.indexOf(currentPage);
index--;
if (index >= 0) {
cardLayout.previous(this);
currentPage = pages.get(index);
}
}
#Override
public void lastPage() {
Page page = pages.get(pages.size() - 1);
showPage(page);
}
#Override
public void firstPage() {
Page page = pages.get(0);
showPage(page);
}
protected void showPage(Page page) {
cardLayout.show(this, page.getName());
currentPage = page;
}
}
public abstract class AbstractPage extends JPanel implements Page, ActionListener {
private NavigationController navigationController;
private JPanel buttons;
private String name;
public AbstractPage(String name, NavigationController navigationController) {
this.name = name;
this.navigationController = navigationController;
setLayout(new BorderLayout());
buttons = new JPanel(new FlowLayout(FlowLayout.RIGHT));
add(buttons, BorderLayout.SOUTH);
}
protected void insertButton(JButton button) {
button.addActionListener(this);
buttons.add(button);
}
#Override
public NavigationController getNavigationController() {
return navigationController;
}
#Override
public JComponent getView() {
return this;
}
#Override
public String getName() {
return super.getName();
}
}
public class FirstPage extends AbstractPage implements Page {
private JButton next = new JButton("Next >");
public FirstPage(String name, NavigationController controller) {
super(name, controller);
JLabel label = new JLabel("First page");
label.setHorizontalAlignment(JLabel.CENTER);
add(label);
insertButton(next);
}
#Override
public void actionPerformed(ActionEvent e) {
if (e.getSource() == next) {
getNavigationController().nextPage();
}
}
}
public class SecondPage extends AbstractPage implements Page {
private JButton next = new JButton("Next >");
private JButton previous = new JButton("< Previous");
public SecondPage(String name, NavigationController controller) {
super(name, controller);
JLabel label = new JLabel("Second page");
label.setHorizontalAlignment(JLabel.CENTER);
add(label);
insertButton(previous);
insertButton(next);
}
#Override
public void actionPerformed(ActionEvent e) {
if (e.getSource() == next) {
getNavigationController().nextPage();
} else if (e.getSource() == previous) {
getNavigationController().previousPage();
}
}
}
public class ThirdPage extends AbstractPage implements Page {
private JButton previous = new JButton("< Previous");
public ThirdPage(String name, NavigationController controller) {
super(name, controller);
JLabel label = new JLabel("Third page");
label.setHorizontalAlignment(JLabel.CENTER);
add(label);
insertButton(previous);
}
#Override
public void actionPerformed(ActionEvent e) {
if (e.getSource() == previous) {
getNavigationController().previousPage();
}
}
}
}
Example #2 - central controller example
This example separates the controller from the pages, so that the buttons are not part of the pages themselves. This frees up the pages/views to be anything you need them to be
import java.awt.BorderLayout;
import java.awt.CardLayout;
import java.awt.Component;
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.HashMap;
import java.util.List;
import java.util.Map;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.border.EmptyBorder;
public class CardLayoutExample2 {
public static void main(String[] args) {
new CardLayoutExample2();
}
public CardLayoutExample2() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new WizardPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class WizardPane extends JPanel {
private List<String> pages;
private String currentPage;
private JButton first;
private JButton previous;
private JButton next;
private JButton last;
private CardLayout cardLayout;
private JPanel contentPane;
public WizardPane() {
setLayout(new BorderLayout());
cardLayout = new CardLayout();
pages = new ArrayList<>(3);
contentPane = new JPanel(cardLayout);
contentPane.setBorder(new EmptyBorder(4, 4, 4, 4));
pages.add("Page01");
pages.add("Page02");
pages.add("Page03");
contentPane.add(new FirstPage(), "Page01");
contentPane.add(new SecondPage(), "Page02");
contentPane.add(new ThirdPage(), "Page03");
JPanel actionsPane = new JPanel(new GridBagLayout());
actionsPane.setBorder(new EmptyBorder(4, 4, 4, 4));
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridx = 0;
gbc.gridy = 0;
actionsPane.add((first = new JButton("<< First")), gbc);
gbc.gridx++;
gbc.weightx = 1;
gbc.anchor = GridBagConstraints.WEST;
actionsPane.add((previous = new JButton("< Previous")), gbc);
gbc.gridx++;
gbc.anchor = GridBagConstraints.EAST;
actionsPane.add((next = new JButton("Next >")), gbc);
gbc.gridx++;
gbc.weightx = 0;
actionsPane.add((last = new JButton("Last >>")), gbc);
add(contentPane);
add(actionsPane, BorderLayout.SOUTH);
NavigationHandler handler = new NavigationHandler();
first.addActionListener(handler);
previous.addActionListener(handler);
next.addActionListener(handler);
last.addActionListener(handler);
gotoFirstPage();
}
protected void gotoFirstPage() {
currentPage = pages.get(0);
cardLayout.show(contentPane, currentPage);
}
protected void gotoPreviousPage() {
int index = pages.indexOf(currentPage);
index--;
if (index >= 0) {
currentPage = pages.get(index);
cardLayout.show(contentPane, currentPage);
}
}
protected void gotoNextPage() {
int index = pages.indexOf(currentPage);
index++;
if (index < pages.size()) {
currentPage = pages.get(index);
cardLayout.show(contentPane, currentPage);
}
}
protected void gotoLastPage() {
currentPage = pages.get(pages.size() - 1);
cardLayout.show(contentPane, currentPage);
}
protected class NavigationHandler implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
if (e.getSource() == first) {
gotoFirstPage();
} else if (e.getSource() == previous) {
gotoPreviousPage();
} else if (e.getSource() == next) {
gotoNextPage();
} else if (e.getSource() == last) {
gotoLastPage();
}
}
}
}
public class FirstPage extends JPanel {
public FirstPage() {
setLayout(new BorderLayout());
JLabel label = new JLabel("Page One");
label.setHorizontalAlignment(JLabel.CENTER);
add(label);
}
}
public class SecondPage extends JPanel {
public SecondPage() {
setLayout(new BorderLayout());
JLabel label = new JLabel("Page Two");
label.setHorizontalAlignment(JLabel.CENTER);
add(label);
}
}
public class ThirdPage extends JPanel {
public ThirdPage() {
setLayout(new BorderLayout());
JLabel label = new JLabel("Page Three");
label.setHorizontalAlignment(JLabel.CENTER);
add(label);
}
}
}
Example #3 - Model based
Or you could use a model based approach (which is probably more preferable), which defines the order in which components are displayed. For example

JTextArea not show

I create an Team application in java. I add a logo which is the combination of Rectangle and Circle in JFrame but after add logo in application JTextArea not shown... Also adding new player not shown...
Here is my code.
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridLayout;
import java.awt.Rectangle;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JTextArea;
public class MainGUI extends JFrame
{
private JLabel teamName;
private JLabel playerCount;
private JLabel maxPlayer;
private JButton createTeam;
private JButton addOnePlayer;
private JButton addRemining;
private JButton exit;
private Team team;
private boolean teamCreated;
private JTextArea text;
Logo logo;
public static void main(String[] args)
{
new MainGUI();
}
public MainGUI()
{
super.setTitle("Team manager");
super.setSize(500,400);
super.setLocation(150,150);
super.setLayout(new BorderLayout());
add(addTopPanel(), BorderLayout.NORTH);
add(textArea(), BorderLayout.CENTER);
add(buttonPanel(), BorderLayout.SOUTH);
Logo logo = new Logo();
logo.setBounds(100, 100, 150,150);
getContentPane().add(logo);
// logo.addSquare(10, 10, 100, 100);
super.setVisible(true);
super.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
private JPanel buttonPanel()
{
JPanel buttonPanel = new JPanel();
buttonPanel.setLayout(new GridLayout(2,2));
createTeam = new JButton("Create Team");
addOnePlayer = new JButton("Add one player");
addRemining = new JButton("Add remaining players");
exit = new JButton("Exit");
buttonPanel.add(createTeam);
buttonPanel.add(addOnePlayer);
buttonPanel.add(addRemining);
buttonPanel.add(exit);
createTeam.addActionListener(new ActionListener()
{
#Override
public void actionPerformed(ActionEvent e)
{
if(!teamCreated)
{
teamCreated = true;
team = new Team();
teamName.setText("Team name: "+team.getName());
playerCount.setText("Players count: "+team.getCount());
maxPlayer.setText("Max team size: "+team.getSize());
}
else
{
JOptionPane.showMessageDialog(null,"The team has been already created, and no further Team instances are instantiated");
}
}
});
addOnePlayer.addActionListener(new ActionListener()
{
#Override
public void actionPerformed(ActionEvent e)
{
if(team != null)
{
Player pl = Team.createPlayer();
team.addPlayer(pl);
playerCount.setText("Players count: "+team.getCount());
text.setText(team.toString());
}
else
{
JOptionPane.showMessageDialog(null,"Create a team first ");
}
}
});
addRemining.addActionListener(new ActionListener()
{
#Override
public void actionPerformed(ActionEvent e)
{
if(team != null)
{
team.addPlayers();
playerCount.setText("Players count: "+team.getCount());
text.setText(team.toString());
}
else
{
JOptionPane.showMessageDialog(null,"Create a team first ");
}
}
});
exit.addActionListener(new ActionListener()
{
#Override
public void actionPerformed(ActionEvent e)
{
System.exit(1);
}
});
return buttonPanel;
}
private JTextArea textArea()
{
text = new JTextArea();
return text;
}
private JPanel addTopPanel()
{
JPanel top = new JPanel();
top.setLayout(new GridLayout(1,3));
teamName = new JLabel("Team name: ");
playerCount = new JLabel("Players count: ");
maxPlayer = new JLabel("Max team size: ");
top.add(teamName);
top.add(playerCount);
top.add(maxPlayer);
return top;
}
class Logo extends JPanel {
/**
*
*/
private static final long serialVersionUID = 1L;
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.orange);
g.drawRect(350,80,70,70);
g.setColor(Color.blue);
g.drawRoundRect(360, 30, 50, 50, 50, 50);;
}
}
}

after add logo in application JTextArea not shown
Reason is this Line:
logo.setBounds(100, 100, 150,150);
getContentPane().add(logo);
setBounds wont work with the layouts of Swing components. So when you are adding the logo in container of JFrame it is adding it to the center , hiding out the JTextArea added in center.