We Keep Coding

Adding an image to a frame by button press

I am trying to implement an image appearing when a button is pressed. For this purpose I thought I could just copy the concept of button 4 (which works) and exchange the System.exit(0) with code to add an image, but while I've been able to use that code elsewhere successfully, here it does not seem to work.
import java.awt.EventQueue;
import javax.swing.JFrame;
import java.awt.FlowLayout;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import javax.swing.JPanel;
import javax.swing.JLabel;
import javax.swing.JComboBox;
import javax.swing.JSpinner;
import java.awt.Color;
import java.util.ArrayList;
public class Mainframe {
private JFrame frmOceanlife;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
Mainframe window = new Mainframe();
window.frmOceanlife.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the application.
*/
public Mainframe() {
initialize();
}
/**
* Initialize the contents of the frame.
*/
private void initialize() {
frmOceanlife = new JFrame();
frmOceanlife.setTitle("OceanLife");
frmOceanlife.setBounds(100, 100, 750, 600);
frmOceanlife.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frmOceanlife.getContentPane().setLayout(null);
JButton btnNewButton_4 = new JButton("Quit");
btnNewButton_4.setBounds(640, 6, 81, 29);
frmOceanlife.getContentPane().add(btnNewButton_4);
btnNewButton_4.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.exit(0);
}
});
JButton btnNewButton_5 = new JButton("Einfügen");
btnNewButton_5.setBounds(410, 34, 103, 29);
frmOceanlife.getContentPane().add(btnNewButton_5);
btnNewButton_5.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
ImageIcon icon = new ImageIcon("Stone.png");
JLabel label = new JLabel(icon);
// label.setBounds(25,25,50,50);
frmOceanlife.getContentPane().add(label);
}
});
JPanel panel = new JPanel();
panel.setBackground(Color.WHITE);
panel.setBounds(70, 75, 600, 450);
panel.setLayout(new FlowLayout());
JLabel piclabel = new JLabel(new ImageIcon("underwater-600x450.png"));
panel.add(piclabel);
frmOceanlife.getContentPane().add(panel);
JLabel lblNewLabel_2 = new JLabel("Welcome to Oceanlife - Your Ocean size is 600x450!");
lblNewLabel_2.setBounds(6, 539, 334, 16);
frmOceanlife.getContentPane().add(lblNewLabel_2);
}
}

The problem is that you are creating a new JLabel and trying to add it to the frame, once the button is pressed. Instead, you should just change the Icon of the label that is already added to the frame (i.e., piclabel), using piclabel.setIcon(icon);. So, you should declare picLabel at the start of your code, so that it can be accessible in the actionPerformed method of your button.
public class Mainframe {
private JFrame frmOceanlife;
JLabel piclabel;
...
Then, instantiate the label in the initialize() method as below:
...
panel.setBounds(70, 75, 600, 450);
panel.setLayout(new FlowLayout());
piclabel = new JLabel(new ImageIcon("underwater-600x450.png"));
...
Finally, your actionPerformed method for btnNewButton_5 (please consider using descriptive names instead) should look like this:
btnNewButton_5.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
ImageIcon icon = new ImageIcon("Stone.png");
piclabel.setIcon(icon);
}
});
Update
If, however, what you want is to add a new JLabel each time, and not change the icon of the existing one, you could use Box object with BoxLayout added to a ScrollPane. Then add the ScrollPane to your JFrame. Working example is shown below, based on the code you provided (again, please consider using descriptive names and removing unecessary code):
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.*;
import javax.swing.*;
public class Mainframe {
private JFrame frmOceanlife;
Box box;
JScrollPane scrollPane;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
Mainframe mf = new Mainframe();
mf.initialize();
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Initialize the contents of the frame.
*/
private void initialize() {
JButton insertBtn = new JButton("Einfügen");
insertBtn.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
ImageIcon icon = new ImageIcon("Stone.png");
JLabel label = new JLabel(icon);
box.add(Box.createRigidArea(new Dimension(0, 5)));// creates space between the JLabels
box.add(label);
frmOceanlife.repaint();
frmOceanlife.revalidate();
Rectangle bounds = label.getBounds();
scrollPane.getViewport().scrollRectToVisible(bounds);// scroll to the new image
}
});
JButton quitBtn = new JButton("Quit");
quitBtn.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.exit(0);
}
});
box = new Box(BoxLayout.Y_AXIS);
JLabel piclabel = new JLabel(new ImageIcon("underwater-600x450.png"));
box.add(piclabel);
scrollPane = new JScrollPane(box);
Dimension dim = new Dimension(box.getComponent(0).getPreferredSize());
scrollPane.getViewport().setPreferredSize(dim);
scrollPane.getVerticalScrollBar().setUnitIncrement(dim.height);
scrollPane.getViewport().setBackground(Color.WHITE);
JPanel controlPanel = new JPanel();
controlPanel.setLayout(new FlowLayout());
controlPanel.add(insertBtn);
controlPanel.add(quitBtn);
JLabel titleLbl = new JLabel("Welcome to Oceanlife - Your Ocean size is 600x450!", SwingConstants.CENTER);
frmOceanlife = new JFrame();
frmOceanlife.getContentPane().add(titleLbl, BorderLayout.NORTH);
frmOceanlife.getContentPane().add(scrollPane, BorderLayout.CENTER);
frmOceanlife.getContentPane().add(controlPanel, BorderLayout.SOUTH);
frmOceanlife.setTitle("OceanLife");
frmOceanlife.pack();
frmOceanlife.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frmOceanlife.setLocationRelativeTo(null);
frmOceanlife.setVisible(true);
}
}

Here is a sample application demonstrating the use of CardLayout. Note that I used [Eclipse] WindowBuilder. All the below code was generated by WindowBuilder apart from the ActionListener implementations. Also note that the ActionListener implementation for quitButton uses a lambda expression while the insertButton implementation uses a method reference.
More notes after the code.
import java.awt.EventQueue;
import javax.swing.JFrame;
import javax.swing.JPanel;
import java.awt.BorderLayout;
import java.awt.CardLayout;
import javax.swing.JLabel;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import javax.swing.ImageIcon;
import javax.swing.JButton;
public class MainFram {
private JFrame frame;
private JPanel cardsPanel;
private JPanel firstPanel;
private JLabel firstLabel;
private JPanel secondPanel;
private JLabel secondLabel;
private JPanel buttonsPanel;
private JButton insertButton;
private JButton quitButton;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
MainFram window = new MainFram();
window.frame.setVisible(true);
}
catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the application.
*/
public MainFram() {
initialize();
}
/**
* Initialize the contents of the frame.
*/
private void initialize() {
frame = new JFrame();
frame.setBounds(100, 100, 450, 300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(getCardsPanel(), BorderLayout.CENTER);
frame.getContentPane().add(getButtonsPanel(), BorderLayout.SOUTH);
}
private JPanel getCardsPanel() {
if (cardsPanel == null) {
cardsPanel = new JPanel();
cardsPanel.setLayout(new CardLayout(0, 0));
cardsPanel.add(getFirstPanel(), "first");
cardsPanel.add(getSecondPanel(), "second");
}
return cardsPanel;
}
private JPanel getFirstPanel() {
if (firstPanel == null) {
firstPanel = new JPanel();
firstPanel.setLayout(new FlowLayout(FlowLayout.CENTER, 5, 5));
firstPanel.add(getFirstLabel());
}
return firstPanel;
}
private JLabel getFirstLabel() {
if (firstLabel == null) {
firstLabel = new JLabel("");
firstLabel.setIcon(new ImageIcon(getClass().getResource("underwater-600x450.png")));
}
return firstLabel;
}
private JPanel getSecondPanel() {
if (secondPanel == null) {
secondPanel = new JPanel();
secondPanel.setLayout(new FlowLayout(FlowLayout.CENTER, 5, 5));
secondPanel.add(getLabel_1());
}
return secondPanel;
}
private JLabel getLabel_1() {
if (secondLabel == null) {
secondLabel = new JLabel("");
secondLabel.setIcon(new ImageIcon(getClass().getResource("Stone.png")));
}
return secondLabel;
}
private JPanel getButtonsPanel() {
if (buttonsPanel == null) {
buttonsPanel = new JPanel();
buttonsPanel.setLayout(new FlowLayout(FlowLayout.CENTER, 5, 5));
buttonsPanel.add(getInsertButton());
buttonsPanel.add(getQuitButton());
}
return buttonsPanel;
}
private JButton getInsertButton() {
if (insertButton == null) {
insertButton = new JButton("Einfügen");
insertButton.addActionListener(this::insertAction);
}
return insertButton;
}
private JButton getQuitButton() {
if (quitButton == null) {
quitButton = new JButton("Quit");
quitButton.addActionListener(e -> System.exit(0));
}
return quitButton;
}
private void insertAction(ActionEvent event) {
CardLayout cardLayout = (CardLayout) cardsPanel.getLayout();
cardLayout.next(cardsPanel);
}
}
The above code requires that the image files, i.e. underwater-600x450.png and Stone.png, be located in the same directory as file MainFram.class. Refer to How to Use Icons.
When you click on the insertButton, the panel containing the underwater-600x450.png image is hidden and the panel containing the Stone.png image is displayed. Clicking the insertButton a second time will hide Stone.png and display underwater-600x450.png. In other words, clicking the insertButton toggles the images.

The first thing to do is using layout managers instead of setting bounds manually:
import java.awt.*;
import javax.swing.*;
public class Mainframe {
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(() -> {
try {
new Mainframe();
} catch (Exception e) {
e.printStackTrace();
}
});
}
/**
* Create the application.
*/
public Mainframe() {
initialize();
}
/**
* Initialize the contents of the frame.
*/
private void initialize() {
JFrame frmOceanlife = new JFrame();
frmOceanlife.setTitle("OceanLife");
//frmOceanlife.setBounds(100, 100, 750, 600);
frmOceanlife.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//frmOceanlife.getContentPane().setLayout(null);
frmOceanlife.setLayout(new BoxLayout(frmOceanlife.getContentPane(), BoxLayout.PAGE_AXIS));
JButton btnNewButton_4 = new JButton("Quit");
btnNewButton_4.addActionListener(e -> System.exit(0));
//btnNewButton_4.setBounds(640, 6, 81, 29);
JPanel quitPanel = new JPanel();
quitPanel.setLayout(new FlowLayout(FlowLayout.RIGHT));
quitPanel.add(btnNewButton_4);
frmOceanlife.getContentPane().add(quitPanel);
JPanel stonesPanel = new JPanel();
frmOceanlife.getContentPane().add(stonesPanel);
JButton btnNewButton_5 = new JButton("Insert");
//btnNewButton_5.setBounds(410, 34, 103, 29);
btnNewButton_5.addActionListener(e -> {
ImageIcon icon = new ImageIcon("Stone.png");
JLabel label = new JLabel(icon);
//label.setBounds(25,25,50,50);
stonesPanel.add(label);
frmOceanlife.revalidate();
});
JPanel insertPanel = new JPanel();
insertPanel.setLayout(new FlowLayout(FlowLayout.CENTER));
insertPanel.add(btnNewButton_5);
frmOceanlife.getContentPane().add(insertPanel);
JPanel panel = new JPanel();
panel.setBackground(Color.WHITE);
//panel.setBounds(70, 75, 600, 450);
panel.setLayout(new FlowLayout());
panel.setPreferredSize(new Dimension(700,550));
JLabel piclabel = new JLabel(new ImageIcon("underwater-600x450.png"));
panel.add(piclabel);
frmOceanlife.getContentPane().add(panel);
JLabel lblNewLabel_2 = new JLabel("Welcome to Oceanlife - Your Ocean size is 600x450!");
//lblNewLabel_2.setBounds(6, 539, 334, 16);
JPanel infoPanel = new JPanel();
infoPanel.setLayout(new FlowLayout(FlowLayout.CENTER));
infoPanel.add(lblNewLabel_2);
frmOceanlife.getContentPane().add(infoPanel);
frmOceanlife.pack();
frmOceanlife.setVisible(true);
}
}
Next, let's introduce better names and use publicly available images to make the code more readable and more of an mre:
import java.awt.*;
import java.net.*;
import javax.swing.*;
public class Mainframe {
private static final String STONE = "https://cdn3.iconfinder.com/data/icons/softwaredemo/PNG/32x32/Circle_Red.png",
OCEAN ="https://media-gadventures.global.ssl.fastly.net/media-server/dynamic/blogs/posts/robin-wu/2014/12/PB110075.jpg";
public Mainframe() {
initialize();
}
private void initialize() {
JFrame frmOceanlife = new JFrame();
frmOceanlife.setTitle("OceanLife");
frmOceanlife.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frmOceanlife.setLayout(new BoxLayout(frmOceanlife.getContentPane(), BoxLayout.PAGE_AXIS));
JButton quitBtn = new JButton("Quit");
quitBtn.addActionListener(e -> System.exit(0));
JPanel quitPanel = new JPanel();
quitPanel.setLayout(new FlowLayout(FlowLayout.RIGHT));
quitPanel.add(quitBtn);
frmOceanlife.getContentPane().add(quitPanel);
JPanel stonesPanel = new JPanel();
frmOceanlife.getContentPane().add(stonesPanel);
JButton insertBtn = new JButton("Insert");
insertBtn.addActionListener(e -> {
try {
ImageIcon icon = new ImageIcon(new URL(STONE));
JLabel stoneLbl = new JLabel(icon);
stonesPanel.add(stoneLbl);
frmOceanlife.revalidate();
} catch (MalformedURLException ex) {
ex.printStackTrace();
}
});
JPanel insertPanel = new JPanel();
insertPanel.setLayout(new FlowLayout(FlowLayout.CENTER));
insertPanel.add(insertBtn);
frmOceanlife.getContentPane().add(insertPanel);
JPanel oceanPanel = new JPanel();
oceanPanel.setBackground(Color.WHITE);
oceanPanel.setLayout(new FlowLayout());
oceanPanel.setPreferredSize(new Dimension(700,550));
try {
JLabel oceanLbl = new JLabel(new ImageIcon(new URL(OCEAN)));
oceanPanel.add(oceanLbl);
} catch (MalformedURLException ex) {
ex.printStackTrace();
}
frmOceanlife.getContentPane().add(oceanPanel);
JLabel infoLabel = new JLabel("Welcome to Oceanlife - Your Ocean size is 600x450!");
JPanel infoPanel = new JPanel();
infoPanel.setLayout(new FlowLayout(FlowLayout.CENTER));
infoPanel.add(infoLabel);
frmOceanlife.getContentPane().add(infoPanel);
frmOceanlife.pack();
frmOceanlife.setVisible(true);
}
public static void main(String[] args) {
//no change in main
}
}
And add some final touchups :
public class Mainframe {
private static final String STONE = "https://cdn3.iconfinder.com/data/icons/softwaredemo/PNG/32x32/Circle_Red.png",
OCEAN ="https://media-gadventures.global.ssl.fastly.net/media-server/dynamic/blogs/posts/robin-wu/2014/12/PB110075.jpg";
private ImageIcon oceanIcon;
public Mainframe() {
initialize();
}
private void initialize() {
JFrame frmOceanlife = new JFrame();
frmOceanlife.setTitle("OceanLife");
frmOceanlife.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frmOceanlife.setLayout(new BoxLayout(frmOceanlife.getContentPane(), BoxLayout.PAGE_AXIS));
JButton quitBtn = new JButton("Quit");
quitBtn.addActionListener(e -> System.exit(0));
JPanel quitPanel = new JPanel();
quitPanel.setLayout(new FlowLayout(FlowLayout.RIGHT));
quitPanel.add(quitBtn);
frmOceanlife.getContentPane().add(quitPanel);
JPanel stonesPanel = new JPanel();
JLabel stoneLbl = new JLabel();
stonesPanel.add(stoneLbl);
frmOceanlife.getContentPane().add(stonesPanel);
JButton insertBtn = new JButton("Insert");
insertBtn.addActionListener(e -> {
try {
ImageIcon icon = new ImageIcon(new URL(STONE));
stoneLbl.setIcon(icon);
} catch (MalformedURLException ex) {
ex.printStackTrace();
}
});
JPanel insertPanel = new JPanel();
insertPanel.setLayout(new FlowLayout(FlowLayout.CENTER));
insertPanel.add(insertBtn);
frmOceanlife.getContentPane().add(insertPanel);
try {
oceanIcon = new ImageIcon(new URL(OCEAN));
} catch (MalformedURLException ex) {
ex.printStackTrace();
}
JLabel oceanLbl = new JLabel();
oceanLbl.setIcon(oceanIcon);
JPanel oceanPanel = new JPanel(){
#Override
public Dimension getPreferredSize() {
return new Dimension(oceanIcon.getIconWidth()+100, oceanIcon.getIconHeight());
};
};
oceanPanel.add(oceanLbl);
oceanPanel.setBackground(Color.WHITE);
oceanPanel.setLayout(new GridBagLayout()); //center image in panel
frmOceanlife.getContentPane().add(oceanPanel);
JLabel infoLabel = new JLabel("Welcome to Oceanlife - Your Ocean size is "+oceanIcon+oceanIcon.getIconWidth()+
"x"+oceanIcon.getIconHeight()+"!");
JPanel infoPanel = new JPanel();
infoPanel.setLayout(new FlowLayout(FlowLayout.CENTER));
infoPanel.add(infoLabel);
frmOceanlife.getContentPane().add(infoPanel);
frmOceanlife.pack();
frmOceanlife.setVisible(true);
}
public static void main(String[] args) {
//no change in main
}
}

How to make JPanel fill the entire JFrame?

I am making an UI in a minecraft plugin. Everything is working, except I have a JPanel and it doesn't fill the whole JFrame. So what I want is the JPanel fill the entire JFrame even if we re-scale the window.
I use Layout manager (FlowLayout) for the JPanel.
I tried using a Layout manager for the JFrame, well it didn't solved my problem because it didn't resize the JPanel.. I tried setting the size of the JPanel to the JFrame's size, but when it's resized it doesn't scale with it.
So, how can I do this?
My plugin creates a button for every player and when I click the button it kicks the player.
My code (I can't really post less because I don't know where I need to change something):
public static JFrame f;
public static JTextField jtf;
public static JPanel jp;
public static void creategui()
{
System.out.println("GUI created.");
f = new JFrame("Players");
jp = new JPanel();
jp.setLayout(new FlowLayout(FlowLayout.LEFT));
jp.setBackground(Color.GRAY);
jtf = new JTextField("Reason");
jtf.setPreferredSize(new Dimension(200,20));
jtf.setToolTipText("Write the reason here.");
jp.setSize(new Dimension(200,200));
f.setLayout(null);
f.setSize(500,500);
f.setVisible(true);
jp.add(jtf);f.add(jp, BorderLayout.CENTER);
for (final Player p : Bukkit.getOnlinePlayers())
{
System.out.println("Looping.");
final JButton b = new JButton();
b.setName(p.getName());
b.setText(p.getName());
b.setToolTipText("Kick " + b.getText());
b.setBackground(Color.GREEN);
b.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if (!b.getBackground().equals(Color.RED))
{
Bukkit.getScheduler().runTask(main, new Runnable() {
public void run() {
Bukkit.getPlayer(b.getText()).kickPlayer(jtf.getText());
b.setBackground(Color.RED);
}
});
}
}
});
jp.add(b);
System.out.println("Button added.");
}
f.add(jp, BorderLayout.CENTER);
}

The question should include an mcve reproducing the problem so we can test it.
It could look like this :
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.util.Arrays;
import java.util.List;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
public class Mcve {
private static List<String> players = Arrays.asList(new String[]{"Player A", "Player B"});
public static void main(String[] args) {
creategui();
}
public static void creategui()
{
JPanel jp = new JPanel();
jp.setBackground(Color.GRAY);
JTextField jtf = new JTextField("Reason");
jtf.setPreferredSize(new Dimension(200,20));
jtf.setToolTipText("Write the reason here.");
jp.setSize(new Dimension(200,200));
jp.add(jtf);
for (final String p : players)
{
final JButton b = new JButton();
b.setText(p);
b.setBackground(Color.GREEN);
b.addActionListener(e -> {
if (!b.getBackground().equals(Color.RED))
{
b.setBackground(Color.RED);
}
});
jp.add(b);
}
JFrame f = new JFrame("Players");
f.setLayout(null);
f.setSize(500,500);
f.add(jp, BorderLayout.CENTER);
f.setVisible(true);
}
}
To make the JPanel fill the entire frame simply remove this line :
f.setLayout(null);
and let the default BorderLayout manager do its work.
Here is a modified version with some additional comments:
public class Mcve {
private static List<String> players = Arrays.asList(new String[]{"Player A", "Player B"});
public static void main(String[] args) {
creategui();
}
public static void creategui()
{
JPanel jp = new JPanel();
jp.setBackground(Color.GRAY);
JTextField jtf = new JTextField("Reason");
jtf.setPreferredSize(new Dimension(200,20));
jtf.setToolTipText("Write the reason here.");
jp.setPreferredSize(new Dimension(250,200)); // set preferred size rather than size
jp.add(jtf);
for (final String p : players)
{
final JButton b = new JButton();
b.setText(p);
b.setBackground(Color.GREEN);
b.addActionListener(e -> {
if (!b.getBackground().equals(Color.RED))
{
b.setBackground(Color.RED);
}
});
jp.add(b);
}
JFrame f = new JFrame("Players");
//f.setLayout(null); null layouts are bad practice
//f.setSize(500,500); let layout managers set the sizes
f.add(jp, BorderLayout.CENTER);
f.pack();
f.setVisible(true);
}
}

A 1x1 grid layout does the job quite nicely.
window = new JFrame();
panel = new JPanel();
window.setLayout(new java.awt.GridLayout(1, 1));
window.add(panel);

Either set the layout manager for jp (the JPanel in the code you posted) to BorderLayout and add jtf (the JTextField in the code you posted) to the CENTER of jp, as in:
f = new JFrame();
jp = new JPanel(new BorderLayout());
jtf = new JTextField(30); // number of columns
jp.add(jtf, BorderLayout.CENTER);
f.add(jp, BorderLayout.CENTER);
or dispense with jp and add jtf directly to f (the JFrame in the code you posted), as in:
f = new JFrame();
jtf = new JTextField(30);
f.add(jtf, BorderLayout.CENTER);
The key is that the CENTER component of BorderLayout expands to fill the available space.

So I fixed it somehow, this is the code:
public static void creategui()
{
System.out.println("GUI created.");
f = new JFrame("Players");
jp = new JPanel();
jp.setBackground(Color.GRAY);
jp.setSize(200,200);
jtf = new JTextField(30);
jtf.setToolTipText("Write the reason here.");
jp.add(jtf);
for (final Player p : Bukkit.getOnlinePlayers())
{
System.out.println("Looping.");
final JButton b = new JButton();
b.setName(p.getName());
b.setText(p.getName());
b.setToolTipText("Kick " + b.getText());
b.setBackground(Color.GREEN);
b.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if (!b.getBackground().equals(Color.RED))
{
Bukkit.getScheduler().runTask(main, new Runnable() {
public void run() {
getplr(b.getText()).kickPlayer(jtf.getText());
b.setBackground(Color.RED);
}
});
}
}
});
jp.add(b);
System.out.println("Button added.");
}
f.setLayout(new BorderLayout());
f.add(jp, BorderLayout.CENTER);
f.setSize(500,500);
f.pack();
f.setVisible(true);
}

Java aligning components in panels

I am trying to add components to SOUTH of a BorderLayout I need it to look like this example.
------------------------------------
| |
| |
| |
| |
| |
| |
|_TxtField|Button_____________Label|
So I need a JTextField and a JButton aligned to the left, and a label aligned to the right. How can I accomplish this? Here is my code below, I have tried to do this using nested panels:
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class BlackjackGUI{
private JFrame frame;
private JPanel panel, panelLeft, panelBottomLeft, panelBottomRight;
private JButton newGameBtn, dealBtn, hitBtn, standBtn;
private JLabel placeBetLbl, playerMoneyLbl;
private JLabel playerCard1Lbl, playerCard2Lbl, playerCard3Lbl,
playerCard4Lbl, playerCard5Lbl, playerCard6Lbl, playerCard7Lbl;
private JLabel dealerCard1Lbl, dealerCard2Lbl, dealerCard3Lbl, dealerCard4Lbl,
dealerCard5Lbl, dealerCard6Lbl, dealerCard7Lbl;
private JLabel playerCardValueLbl, dealerCardValueLbl;
private JLabel spacer1, spacer2;
private JTextField betInputBox;
public BlackjackGUI(){
createForm();
addTextField();
addButtons();
addLabels();
frame.add(panel);
frame.setVisible(true);
}
public void createForm() {
frame = new JFrame("Blackjack");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(1200,800);
panel = new JPanel();
panel.setLayout(new BorderLayout());
Color c = new Color(0, 100, 0);
panel.setBackground(c);
panelLeft = new JPanel();
Color panelLeftBG = new Color (23, 25, 100);
panelLeft.setBackground(panelLeftBG);
panel.add(panelLeft, BorderLayout.WEST);
panelBottomLeft = new JPanel();
Color panelBottomLeftBG = new Color (56, 12, 10);
panelBottomLeft.setBackground(panelBottomLeftBG);
panelBottomLeft.setLayout(new FlowLayout(FlowLayout.LEFT));
panel.add(panelBottomLeft, BorderLayout.SOUTH);
panelBottomRight = new JPanel();
Color panelBottomRightBG = new Color (12, 88, 40);
panelBottomRight.setBackground(panelBottomRightBG);
panelBottomRight.setLayout(new FlowLayout(FlowLayout.RIGHT));
panel.add(panelBottomRight, BorderLayout.SOUTH);
}
public void addButtons() {
newGameBtn = new JButton("New Game");
panelLeft.add(newGameBtn, BorderLayout.WEST);
newGameBtn.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent event) {
System.exit(0);
}
});
dealBtn = new JButton("Deal");
dealBtn.setPreferredSize(new Dimension (100, 50));
panelBottomLeft.add(dealBtn);
newGameBtn.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent event) {
System.exit(0);
}
});
}
public void addTextField() {
betInputBox = new JTextField();
betInputBox.setPreferredSize(new Dimension(175,50));
panelBottomLeft.add(betInputBox);
}
public void addLabels() {
placeBetLbl = new JLabel("Place your bets!");
placeBetLbl.setFont(new Font("Gill Sans MT", Font.PLAIN, 35));
panelBottomLeft.add(placeBetLbl);
playerMoneyLbl = new JLabel("£2,500");
playerMoneyLbl.setFont(new Font("Gill Sans MT", Font.PLAIN, 35));
playerMoneyLbl.setLayout(new FlowLayout(FlowLayout.RIGHT));
panelBottomRight.add(playerMoneyLbl);
}
public static void main(String[] args) {
new BlackjackGUI();
}
}

One way is to use a horizontal Box Layout on the panel. Then you can use glue to separate the groups of components:
JPanel panel = new JPanel();
panel.setLayout(...);
panel.add(textField);
panel.add(button);
panel.add(the glue here);
panel.add(label);
Read the section from the Swing tutorial on How to Use BoxLayout for more information on the glue and working examples.

how to do keypress event in jpanel text field?

when i select something in combobox :
it show joptionPane Dialog box wiht two inputs.
here i want to first focusing amount field and then, when i entered in amount field its goes to no of App field then enter go to OK .
Here is my code for JOption Dialog:
JTextField xField = new JTextField(5);
JTextField yField = new JTextField(5);
JPanel myPanel = new JPanel();
myPanel.add(new JLabel("Amount:"));
myPanel.add(xField);
myPanel.add(Box.createHorizontalStrut(15)); // a spacer
myPanel.add(new JLabel("No of App:"));
myPanel.add(yField);
int value = 0;
xField.requestFocus();
int result = JOptionPane.showConfirmDialog(null, myPanel, "Please Enter Amount and No.of app", JOptionPane.OK_CANCEL_OPTION);

You simply try to focus a component which is not layout in a window.
Replace
xField.requestFocus();
by
SwingUtilities.invokeLater(new Runnable() {
public void run() {
xField.requestFocusInWindow();
}
});

You can create your own JDialog on the event that an item has changed to a new item. Then, you can get values entered in the JDialog and appropriately set the information in your parent. If you want to change the order of focus, use a custom focus policy. If you want to change the traversal focus key to the Enter key, you should re-map the key so that it reacts the same as the Tab key. There are several resources online and on this site with information on how to do that.
You should note that the default focus traversal policy is dependent on the order in which you add you elements to your content panel.
I have created a simple example for you on using a JDialog:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.*;
public class RankSelection extends JFrame {
private static final long serialVersionUID = 1L;
private JPanel contentPane;
private JTextField textField;
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
RankSelection frame = new RankSelection();
frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
public RankSelection() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
contentPane = new JPanel();
contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
contentPane.setLayout(new BorderLayout(0, 0));
setContentPane(contentPane);
JComboBox<String> comboBox = new JComboBox<String>();
comboBox.setModel(new DefaultComboBoxModel<String>(new String[] {"Slave", "Peasant", "Minion", "Knight", "Bishop", "Prince", "Coder King"}));
comboBox.addItemListener(new ItemListener() {
#Override
public void itemStateChanged(ItemEvent e) {
if(e.getStateChange() == ItemEvent.SELECTED){
Amount amount = new Amount();
textField.setText(Integer.toString((Integer) amount.getStinkiness().getValue()));
}
}
});
contentPane.add(comboBox, BorderLayout.CENTER);
JLabel lblYourRank = new JLabel("Your Rank");
contentPane.add(lblYourRank, BorderLayout.NORTH);
JPanel panel = new JPanel();
contentPane.add(panel, BorderLayout.SOUTH);
JLabel lblYourStinkiness = new JLabel("Your Stinkiness:");
panel.add(lblYourStinkiness);
textField = new JTextField();
textField.setEditable(false);
textField.setEnabled(false);
textField.setText("0");
panel.add(textField);
textField.setColumns(10);
pack();
}
}
The custom JDialog:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.*;
public class Amount extends JDialog {
private static final long serialVersionUID = 1L;
private final JPanel contentPanel = new JPanel();
private JSpinner amount;
private JSpinner stinkiness;
public Amount() {
setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
setModalityType(ModalityType.APPLICATION_MODAL);
getContentPane().setLayout(new BorderLayout());
contentPanel.setLayout(new FlowLayout());
contentPanel.setBorder(new EmptyBorder(5, 5, 5, 5));
getContentPane().add(contentPanel, BorderLayout.CENTER);
JLabel lblAmount = new JLabel("Amount:");
amount = new JSpinner();
JLabel lblStinkiness = new JLabel("Stinkiness:");
stinkiness = new JSpinner();
contentPanel.add(lblAmount);
contentPanel.add(amount);
contentPanel.add(lblStinkiness);
contentPanel.add(stinkiness);
JPanel buttonPane = new JPanel();
buttonPane.setLayout(new FlowLayout(FlowLayout.CENTER));
getContentPane().add(buttonPane, BorderLayout.SOUTH);
JButton okButton = new JButton("OK");
okButton.setActionCommand("OK");
buttonPane.add(okButton);
getRootPane().setDefaultButton(okButton);
okButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
dispose();
}
});
pack();
setVisible(true);
}
public JSpinner getAmount() {
return amount;
}
public JSpinner getStinkiness() {
return stinkiness;
}
}

Dynamically add components to a JDialog on button click

I want to know how to add components dynamically to a JDialog. I know there is a similar question on SO here, but as you can see, I have his solution as a part of my code.
So the idea is that on click of the button, I need to add a component on the dialog. The sample code is below:
import java.awt.Container;
import java.awt.Dialog;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class Test extends JFrame {
/**
*
*/
private static final long serialVersionUID = 1L;
public static void main(String args[]) {
Test test = new Test();
test.createDialog();
}
public void createDialog() {
DynamicDialog dialog = new DynamicDialog(this);
dialog.setSize(300, 300);
dialog.setVisible(true);
}
}
class DynamicDialog extends JDialog {
/**
*
*/
private static final long serialVersionUID = 1L;
public DynamicDialog(final JFrame owner) {
super(owner, "Dialog Title", Dialog.DEFAULT_MODALITY_TYPE);
final JPanel mainPanel = new JPanel();
mainPanel.setLayout(new BoxLayout(mainPanel, BoxLayout.Y_AXIS));
final JPanel panel = new JPanel();
panel.setLayout(new BoxLayout(panel, BoxLayout.X_AXIS));
panel.add(Box.createRigidArea(new Dimension(3, 10)));
panel.add(createLabel("Click on add"));
panel.add(Box.createRigidArea(new Dimension(23, 10)));
panel.add(createLabel("To add another line of text"));
panel.add(Box.createHorizontalGlue());
mainPanel.add(panel);
mainPanel.add(Box.createRigidArea(new Dimension(3, 10)));
JPanel buttonPanel = new JPanel();
buttonPanel.setLayout(new BoxLayout(buttonPanel, BoxLayout.Y_AXIS));
buttonPanel.add(Box.createHorizontalGlue());
JButton button = new JButton();
button.setText("Add another line");
buttonPanel.add(button);
mainPanel.add(buttonPanel);
mainPanel.add(Box.createRigidArea(new Dimension(3, 10)));
button.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent event) {
Container contentPane = owner.getContentPane();
JPanel _panel = new JPanel();
_panel.setLayout(new BoxLayout(_panel, BoxLayout.X_AXIS));
_panel.add(Box.createHorizontalGlue());
_panel.add(createLabel("Added!"));
contentPane.add(_panel);
contentPane.validate();
contentPane.repaint();
owner.pack();
}
});
pack();
setLocationRelativeTo(owner);
this.add(mainPanel);
}
JLabel createLabel(String name) {
JLabel label = new JLabel(name);
return label;
}
}

If you add it to the main panel it will work, you were adding it to the content pane of the frame which it seems it does not show up anywhere.
button.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent event) {
JPanel _panel = new JPanel();
_panel.setLayout(new BoxLayout(_panel, BoxLayout.X_AXIS));
_panel.add(Box.createHorizontalGlue());
_panel.add(createLabel("Added!"));
mainPanel.add(_panel);
mainPanel.validate();
mainPanel.repaint();
owner.pack();
}
})