Develop Reference

Gui Interactions

This is my first time creating a Gui and I'm stumped on how to create interactions.
I'm trying to implement a single selection mode when the combobox is on single, and multiple when it's placed on multiple. I placed them on the multi line comment.
Any ideas?
//Interactions
//When “Single” is selected then the JList changes so only one item
can be selected.
//When “Multiple” is selected, the JList changes so multiple items can
be selected
//When a country, or multiple countries, is selected the JLabel
changes to reflect the new selections
public class GuiTest {
public static String[] Countries = {"Africa", "Haiti", "USA", "Poland", "Russia", "Canada", "Mexico", "Cuba"};
public static String[] Selection = {"Single", "Multiple"};
JPanel p = new JPanel();
JButton b = new JButton("Testing");
JComboBox jc = new JComboBox(Selection);
JList jl = new JList(Countries);
private static void constructGUI() {
JFrame.setDefaultLookAndFeelDecorated(true);
JFrame frame = new JFrame();
frame.setTitle("Countries Selection");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// add a JLabel that says Welcome
JLabel label = new JLabel("Selected Items:");
frame.add(label);
frame.pack();
JComboBox jc = new JComboBox(Selection);
frame.add(jc);
frame.pack();
frame.setVisible(true);
JList jl = new JList(Countries);
frame.add(jl);
frame.pack();
JComponent panel = new JPanel();
panel.setLayout(new FlowLayout());
panel.add(new JLabel("Choose Selection Mode:"));
panel.add(jc);
frame.add(panel, BorderLayout.NORTH);
frame.add(jl, BorderLayout.WEST);
frame.add(label, BorderLayout.SOUTH);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
constructGUI();
}
});
}
}

you should start adding the modes to the ComboBox:
comboBoxCategoria.addItem("Single",0);
comboBoxCategoria.addItem("Multiple",1);
then add a ActionListener to your ComboBox to modify the list selection mode
jc.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
if(jc.getSelectedItem().equals("Single")){
jl.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
}else{//must equals
jl.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);
}
}
});
finally add a MouseListener on the list to detect changes on the list selections and change the JLabel to reflect the new selections
jl.addMouseListener(new MouseAdapter() {
#Override
public void mouseReleased(MouseEvent e) {
label.setText(list.getSelectedValuesList().toString());
}
});
edit: you should also add a KeyListener to update the label since the selection can be changed via arrow keys
jl.addKeyListener(new KeyAdapter() {
#Override
public void keyReleased(KeyEvent e) {
label.setText(list.getSelectedValuesList().toString());
}
});

It would be something like this:
jc.addActionListener((evt) -> {
if ("Single".equals(jc.getSelectedItem())) {
jl.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
int[] sel = jl.getSelectedIndices();
if (sel != null && sel.length > 1) {
jl.setSelectedIndex(sel[0]);
}
} else {
jl.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);
}
});
jl.addListSelectionListener((evt) -> {
StringBuilder buf = new StringBuilder();
for (Object o: jl.getSelectedValuesList()) {
if (buf.length() > 0) {
buf.append(", ");
}
buf.append(o);
}
label.setText(buf.toString());
});
jc.setSelectedItem("Single");

Why is Plot2DPanel not reacting to its MouseListener's click event?

I learned recently how to switch between Jpanels in CardLayout.
The code works fine but when I attempt to change one of jPanels to Plot2DPanel I get a strange behaviour at runtime. The Plot2DPanel isn't picking up its mouse click events. What have I done wrong? (I assume that is not a bug in jmathplot).
Here's the code:
public class Window {
private JFrame frame;
private JPanel cards;
private JPanel panelOne;
private Plot2DPanel panelTwo;
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
Window window = new Window();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
public Window() {
initialize();
}
private void initialize() {
frame = new JFrame();
frame.setBounds(100, 100, 790, 483);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
cards = new JPanel();
cards.setLayout(new CardLayout());
panelOne = new JPanel();
panelOne.setBackground(Color.BLACK);
panelOne.addMouseListener(new MouseAdapter() {
public void mouseClicked(MouseEvent e){
java.awt.Toolkit.getDefaultToolkit().beep(); //debug beep
CardLayout cl = (CardLayout) cards.getLayout();
cl.next(cards);
}
});
panelTwo = new Plot2DPanel();
panelTwo.setBackground(Color.WHITE);
panelTwo.addMouseListener(new MouseAdapter() {
public void mouseClicked(MouseEvent e){
java.awt.Toolkit.getDefaultToolkit().beep(); //debug beep
CardLayout cl = (CardLayout) cards.getLayout();
cl.next(cards);
}
});
cards.add(panelOne, "panel1");
cards.add(panelTwo, "panel2");
frame.getContentPane().add(cards);
}
}

Java Smileys Replacing String with Smiley

I'm writing a Chat program. I designed a mock-up gui with smileys where when the user clicks on a smiley(jbutton) it prints it onto a textpane. I managed to add an advanced feature where when a user types in ":)" and sends it, it inserts the smiley instead of the string - using the insertIcon() method. The problem I have is that it only prints the smiley once rather than multiple times. So if I type "Hi :) My name is Jack :)" it only inserts the icon ONCE. Any suggestions?
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class SmileyTesterGUI extends JFrame {
JPanel main = new JPanel();
JPanel south = new JPanel();
JPanel messageCenter = new JPanel();
JPanel smileysNorth = new JPanel();
JTextField text;
JTextPane tPane;
Icon happy;
Icon smile;
Icon tongue;
Icon veryHappy;
Icon wink;
Icon laugh;
Icon sad;
Icon verySad;
Icon cry;
public SmileyTesterGUI() {
super("Smileys");
add(main);
main.setLayout(new BorderLayout());
main.add(south, BorderLayout.SOUTH);
south.setLayout(new BorderLayout());
south.add(messageCenter, BorderLayout.CENTER);
south.add(smileysNorth, BorderLayout.NORTH);
// textpane panel
tPane = new JTextPane();
JScrollPane sPane = new JScrollPane(tPane);
main.add(sPane);
tPane.setEditable(false);
// smileysPanel
smileysNorth.setLayout(new GridLayout(1, 0));
JButton smiley1 = new JButton();
JButton smiley2 = new JButton();
JButton smiley3 = new JButton();
JButton smiley4 = new JButton();
JButton smiley5 = new JButton();
JButton smiley6 = new JButton();
JButton smiley7 = new JButton();
JButton smiley8 = new JButton();
JButton smiley9 = new JButton();
smileysNorth.add(smiley1);
smileysNorth.add(smiley2);
smileysNorth.add(smiley3);
smileysNorth.add(smiley4);
smileysNorth.add(smiley5);
smileysNorth.add(smiley6);
smileysNorth.add(smiley7);
smileysNorth.add(smiley8);
smileysNorth.add(smiley9);
// set smileys(icon) to each button - pathed from personal directory
happy = new ImageIcon(getClass().getResource("smileys/Smile1.png"));
smiley1.setIcon(happy);
smile = new ImageIcon(getClass().getResource("smileys/Smile2.png"));
smiley2.setIcon(smile);
tongue = new ImageIcon(getClass().getResource("smileys/Smile3.png"));
smiley3.setIcon(tongue);
veryHappy = new ImageIcon(getClass().getResource("smileys/Smile4.png"));
smiley4.setIcon(veryHappy);
wink = new ImageIcon(getClass().getResource("smileys/Smile5.png"));
smiley5.setIcon(wink);
laugh = new ImageIcon(getClass().getResource("smileys/Smile6.png"));
smiley6.setIcon(laugh);
sad = new ImageIcon(getClass().getResource("smileys/Smile7.png"));
smiley7.setIcon(sad);
verySad = new ImageIcon(getClass().getResource("smileys/Smile8.png"));
smiley8.setIcon(verySad);
cry = new ImageIcon(getClass().getResource("smileys/Smile9.png"));
smiley9.setIcon(cry);
// smileys print on the textpane
smiley1.addMouseListener(new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent e) {
tPane.insertIcon(new ImageIcon(getClass().getResource(
"smileys/Smile1.png")));
}
});
smiley2.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
tPane.insertIcon(new ImageIcon(getClass().getResource(
"smileys/Smile2.png")));
}
});
smiley3.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
tPane.insertIcon(new ImageIcon(getClass().getResource(
"smileys/Smile3.png")));
}
});
smiley4.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
tPane.insertIcon(new ImageIcon(getClass().getResource(
"smileys/Smile4.png")));
}
});
smiley5.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
tPane.insertIcon(new ImageIcon(getClass().getResource(
"smileys/Smile5.png")));
}
});
smiley6.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
tPane.insertIcon(new ImageIcon(getClass().getResource(
"smileys/Smile6.png")));
}
});
smiley7.addMouseListener(new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent e) {
tPane.insertIcon(new ImageIcon(getClass().getResource(
"smileys/Smile7.png")));
}
});
smiley8.addMouseListener(new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent e) {
tPane.insertIcon(new ImageIcon(getClass().getResource(
"smileys/Smile8.png")));
}
});
smiley9.addMouseListener(new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent e) {
tPane.insertIcon(new ImageIcon(getClass().getResource(
"smileys/Smile9.png")));
}
});
// messagePanel
messageCenter.setLayout(new BorderLayout());
text = new JTextField();
JButton send = new JButton("Send");
messageCenter.add(text);
messageCenter.add(send, BorderLayout.EAST);
text.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
sendMessage();
}
});
send.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
sendMessage();
}
});
setLocation(500, 0);
setSize(600, 250);
}
public void sendMessage() {
String a = text.getText();
// tPane.setText(a);
// tPane.getText();
if (a.equals(":D")) {
tPane.insertIcon(veryHappy);
} else if (a.equals(":)")) {
tPane.insertIcon(smile);
} else if (a.equals(":(")) {
tPane.insertIcon(sad);
} else if (a.equalsIgnoreCase(":P")) {
tPane.insertIcon(tongue);
} else if (a.equals(";)")) {
tPane.insertIcon(wink);
}
text.setText(null);
text.requestFocus();
}
public static void main(String[] args) {
new SmileyTesterGUI().setVisible(true);
}
}

insertIcon() method of JTextPane uses selection (caret position in simplest case). So in your case you always replace the icon just once.
Your sendMessage() doesn't check multiple occurences of ":)" in the message. Use while loop obtaining indexes of the ":)" and for each index make it selected and then use insertIcon()

Java how to add image as background in layout

I have a class that uses a CardLayout which has two cards that have a button on them. What I would like to be able to do is put an image that would act like a background such as a desktop background in Windows. The program eventually will have several different cards and I'd like to be able to put different backgrounds on each card. I've tried many suggestions posed in other similar questions on this site as well as whatever I can find through googling it, but I just can't seem to get it to work. I understand that with the CardLayout I can't put a panel on top of a panel, so putting an image on a JPanel wouldn't work. So my question is, based off the code posted below, is there a better way for me to setup my layout so that it works better, and also, how should I approach displaying the image so that it is in the background of the buttons? Any help would be greatly appreciated.
import java.awt.*;
import java.awt.event.*;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.*;
public class Cards implements ActionListener {
private JPanel cards;
private JButton button1;
private JButton button2;
private Image backgroundImage;
public void addComponentToPane(Container pane) throws IOException {
backgroundImage = ImageIO.read(new File("background.jpg"));
//create cards
JPanel card1 = new JPanel()
{
#Override
public void paintComponent(Graphics g)
{
g.drawImage(backgroundImage, 0, 0, null);
}
};
JPanel card2 = new JPanel();
button1 = new JButton("Button 1");
button2 = new JButton("Button 2");
button1.addActionListener(this);
button2.addActionListener(this);
card1.add(button1);
card2.add(button2);
//create panel that contains cards
cards = new JPanel(new CardLayout());
cards.add(card1, "Card 1");
cards.add(card2, "Card 2");
pane.add(cards, BorderLayout.SOUTH);
}
public void itemStateChanged(ItemEvent evt) {
CardLayout cl = (CardLayout)(cards.getLayout());
cl.show(cards, (String)evt.getItem());
}
public static void createAndShowGUI() throws IOException {
//create and setup window
JFrame frame = new JFrame("Frame");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//create and setup content pane
Cards main = new Cards();
main.addComponentToPane(frame.getContentPane());
//display window
frame.pack();
frame.setSize(800, 600);
frame.setResizable(false);
frame.setVisible(true);
}
public void actionPerformed(ActionEvent ae) {
if (ae.getSource() == button1) {
CardLayout cl = (CardLayout) (cards.getLayout());
cl.show(cards, "Card 2");
} else if (ae.getSource() == button2) {
CardLayout cl = (CardLayout) (cards.getLayout());
cl.show(cards, "Card 1");
}
}
public static void main(String[] args) {
//set look and feel
try {
UIManager.setLookAndFeel("javax.swing.plaf.metal.MetalLookAndFeel");
} catch (UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
} catch (IllegalAccessException ex) {
ex.printStackTrace();
} catch (InstantiationException ex) {
ex.printStackTrace();
} catch (ClassNotFoundException ex) {
ex.printStackTrace();
}
//schedule job for the event dispatch thread creating and showing GUI
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
try {
createAndShowGUI();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
}
}

You need to override the method paintComponent(Graphics g) of JPanel and use drawImage() on the Graphics object g as in this example.
Also, check these two examples by #trashgod:
example.
example.

#Eng.Fouad's answer is well chosen, but the image probably dominates the layout. You might want to override getPreferredSize() as shown below. Then you can just pack() the window, and the size will be right. See also Loading Images Using getResource.
import java.awt.*;
import java.awt.event.*;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.*;
public class Cards implements ActionListener {
private JPanel cards;
private JButton button1;
private JButton button2;
private Image backgroundImage;
public void addComponentToPane(Container pane) {
try {
backgroundImage = ImageIO.read(new File("background.jpg"));
} catch (IOException ex) {
ex.printStackTrace(System.err);
}
//create cards
JPanel card1 = new JPanel() {
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(backgroundImage, 0, 0, null);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(
backgroundImage.getWidth(null),
backgroundImage.getHeight(null));
}
};
JPanel card2 = new JPanel();
button1 = new JButton("Button 1");
button2 = new JButton("Button 2");
button1.addActionListener(this);
button2.addActionListener(this);
card1.add(button1);
card2.add(button2);
//create panel that contains cards
cards = new JPanel(new CardLayout());
cards.add(card1, "Card 1");
cards.add(card2, "Card 2");
pane.add(cards, BorderLayout.SOUTH);
}
public void itemStateChanged(ItemEvent evt) {
CardLayout cl = (CardLayout) (cards.getLayout());
cl.show(cards, (String) evt.getItem());
}
public static void createAndShowGUI() {
//create and setup window
JFrame frame = new JFrame("Frame");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//create and setup content pane
Cards main = new Cards();
main.addComponentToPane(frame.getContentPane());
//display window
frame.pack();
frame.setVisible(true);
}
public void actionPerformed(ActionEvent ae) {
if (ae.getSource() == button1) {
CardLayout cl = (CardLayout) (cards.getLayout());
cl.show(cards, "Card 2");
} else if (ae.getSource() == button2) {
CardLayout cl = (CardLayout) (cards.getLayout());
cl.show(cards, "Card 1");
}
}
public static void main(String[] args) {
//schedule job for the event dispatch thread creating and showing GUI
EventQueue.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
}

Display java JPanel in a JFrame

I'm having problems getting my JPanel to display properly. I want to use different extended JPanels to display what I want the user to do with this program (which is ultimately to display photographs). Below is the code for the only two classes that exist at this point. Unfortunately, I'm having problems just getting this to work right out of the gate with the first panel which was to present the user with the ability to select different graphic images.
What's happening is, I can't get my JPanel to display until I click the "Open" menu item in the File menu. Once that JOptionPane shows, so does my JPanel (NewAlbum).
class PhotoGallery {
static JPanel transientPanel = null;
static final JFrame mainFrame = new JFrame("Photo Gallery");
public static void main(String[] args) {
JMenu fileMenu = new JMenu("File");
fileMenu.setMnemonic(KeyEvent.VK_F);
JMenuItem open = new JMenuItem("Open");
open.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
JOptionPane.showMessageDialog(mainFrame, "Hello World");
}
});
fileMenu.add(open);
JMenuItem newAlbum = new JMenuItem("New Album");
open.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
AssignToTransientPanel((JPanel) new NewAlbum());
Container content = mainFrame.getContentPane();
content.removeAll();
content.add(transientPanel);
content.validate();
content.repaint();
}
});
fileMenu.add(newAlbum);
JMenuItem exit = new JMenuItem("Exit");
exit.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.exit(0);
}
});
fileMenu.add(exit);
JMenuBar pgMenu = new JMenuBar();
pgMenu.add(fileMenu);
mainFrame.setJMenuBar(pgMenu);
mainFrame.setSize(640, 480);
mainFrame.setLocation(20, 45);
mainFrame.validate();
mainFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
mainFrame.setVisible(true);
}
public static void AssignToTransientPanel(JPanel jp) {
if(transientPanel != null)
mainFrame.remove(transientPanel);
transientPanel = jp;
}
}
}
class NewAlbum extends JPanel {
JButton selectImages = new JButton("Select Images");
JFileChooser jfc;
File[] selectedFiles;
public NewAlbum() {
selectImages.setLocation(25, 25);
add(selectImages);
selectImages.addActionListener(new ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent ae) {
jfc = new JFileChooser();
jfc.setMultiSelectionEnabled(true);
jfc.showOpenDialog(getParent());
selectedFiles = jfc.getSelectedFiles();
}
});
this.validate();
}
public int getHeight() {
return getParent().getSize().height - 20;
}
public int getWidth() {
return getParent().getSize().width - 20;
}
public Dimension getPreferredSize() {
return new Dimension(this.getWidth(), this.getHeight());
}
}

You have not added any components to the mainFrame's content pane in the main method. The only time a panel gets added is in this ActionListener:
open.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
AssignToTransientPanel((JPanel) new NewAlbum());
Container content = mainFrame.getContentPane();
content.removeAll();
content.add(transientPanel);
content.validate();
content.repaint();
}
});
This is only getting called when "Open" is clicked as you have, I assume accidentally, added the ActionListener to the open JMenuItem rather than the newAlbum JMenuItem. To add content on startup you need to add something like this before the mainFrame.setVisible(true) line:
mainFrame.add(new NewAlbum());
BTW, the convention is for all methods in Java source code to start with a lower case letter. assignToTransientPanel would be a better name for your method.