I am trying to create a Java GUI application that contains a label and button. When the button is clicked the background color of the first panel is changed. I've got the label and button but getting errors whenever I click the button. Also, I wanted the first panel to originally have a yellow background then switch to whatever color. Here's my code:
import javax.swing.JFrame;
import javax.swing.JPanel;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.GridLayout;
import java.awt.FlowLayout;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import javax.swing.JLabel;
public class ChangeDemo extends JFrame implements ActionListener
{
public static final int WIDTH = 300;
public static final int HEIGHT= 200;
private JPanel biggerPanel;
public static void main(String[] args)
{
ChangeDemo gui = new ChangeDemo();
gui.setVisible(true);
}
public ChangeDemo()
{
super ("ChangeBackgroundDemo");
setSize(WIDTH,HEIGHT);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLayout(new GridLayout(2,3));
JPanel biggerPanel = new JPanel();
biggerPanel.setLayout(new BorderLayout());
biggerPanel.setBackground(Color.YELLOW);
JLabel namePanel = new JLabel("Click the button to change the background color");
biggerPanel.add(namePanel, BorderLayout.NORTH);
add(namePanel);
JPanel buttonPanel = new JPanel();
buttonPanel.setLayout(new FlowLayout());
buttonPanel.setBackground(Color.LIGHT_GRAY);
JButton changeButton = new JButton("Change Color");
changeButton.addActionListener(this);
buttonPanel.add(changeButton);
add(buttonPanel);
}
public void actionPerformed(ActionEvent e)
{
String buttonString = e.getActionCommand();
if(buttonString.equals("Change Color"))
biggerPanel.setBackground(Color.RED);
else
System.out.println("Unexpected Error!");
}
}
I made a few changes to your code.
First, you must start a Swing application with a call to SwingUtilities.invokeLater.
public static void main(String[] args) {
SwingUtilities.invokeLater(new ChangeDemo());
}
Second, you use Swing components. You only extend a Swing component when you want to override a method of the Swing component.
Third, I made a action listener specifically for your JButton. That way, you don't have to check for a particular JButton string. You can create as many action listeners as you need for your GUI.
JButton changeButton = new JButton("Change Color");
changeButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent event) {
isYellow = !isYellow;
if (isYellow) buttonPanel.setBackground(Color.YELLOW);
else buttonPanel.setBackground(Color.RED);
}
});
Finally, I changed the background color of the JButton panel.
Here's the entire ChangeDemo class.
package com.ggl.testing;
import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class ChangeDemo implements Runnable {
private boolean isYellow;
private JFrame frame;
public static void main(String[] args) {
SwingUtilities.invokeLater(new ChangeDemo());
}
#Override
public void run() {
frame = new JFrame("Change Background Demo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel mainPanel = new JPanel();
mainPanel.setLayout(new BoxLayout(mainPanel, BoxLayout.PAGE_AXIS));
JPanel namePanel = new JPanel();
JLabel nameLabel = new JLabel(
"Click the button to change the background color");
nameLabel.setAlignmentX(JLabel.CENTER_ALIGNMENT);
namePanel.add(nameLabel);
mainPanel.add(namePanel);
final JPanel buttonPanel = new JPanel();
buttonPanel.setLayout(new FlowLayout());
buttonPanel.setBackground(Color.YELLOW);
isYellow = true;
JButton changeButton = new JButton("Change Color");
changeButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent event) {
isYellow = !isYellow;
if (isYellow) buttonPanel.setBackground(Color.YELLOW);
else buttonPanel.setBackground(Color.RED);
}
});
buttonPanel.add(changeButton);
mainPanel.add(buttonPanel);
frame.add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
}
Here is working demo based on amendments to your code, haven't had time to tidy it up but hopefully you'll get the gist of it. Problem was you hand't added Panels to the borders (north, south etc.) in order to color them. Hopefully this helps.
import javax.swing.JFrame;
import javax.swing.JPanel;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.GridLayout;
import java.awt.FlowLayout;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import javax.swing.JLabel;
public class ChangeDemo extends JFrame implements ActionListener
{
public static final int WIDTH = 300;
public static final int HEIGHT= 200;
private JPanel biggerPanel = new JPanel();
private JPanel namePanel = new JPanel();
public static void main(String[] args)
{
ChangeDemo gui = new ChangeDemo();
gui.setVisible(true);
}
public ChangeDemo()
{
super ("ChangeBackgroundDemo");
setSize(WIDTH,HEIGHT);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLayout(new GridLayout(2,3));
//JPanel biggerPanel = new JPanel();
this.biggerPanel.setLayout(new BorderLayout());
this.biggerPanel.setBackground(Color.YELLOW);
JLabel nameLabel = new JLabel("Click the button to change the background color");
namePanel.add(nameLabel);
namePanel.setBackground(Color.YELLOW);
//this.biggerPanel.add(namePanel, BorderLayout.NORTH);
add(namePanel);
JPanel buttonPanel = new JPanel();
buttonPanel.setLayout(new FlowLayout());
buttonPanel.setBackground(Color.LIGHT_GRAY);
JButton changeButton = new JButton("Change Color");
changeButton.addActionListener(this);
changeButton.setActionCommand("Change Color");
buttonPanel.add(changeButton);
add(buttonPanel);
}
public void actionPerformed(ActionEvent e)
{
String buttonString = e.getActionCommand();
if(buttonString.equals("Change Color"))
this.namePanel.setBackground(Color.RED);
else
System.out.println("Unexpected Error!");
}
}
Related
I failed to change the height of JPanel or JScrollPane to make more lines to appear, I used GridLayout. It seems that, every component in it should have the same size even when I use setSize(). Should I use another layout?
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextField;
public class Main {
private JFrame mainFrame;
private JLabel headerLabel;
private JLabel statusLabel;
private JPanel controlPanel;
private imagePanel image;
JTextField textField = new JTextField(20);
public Main() throws IOException{
prepareGUI();
}
class imagePanel extends JPanel {
private static final long serialVersionUID = 1L;
public void paint(Graphics g) {
try {
BufferedImage image = ImageIO.read(new File("file.jpg"));
g.drawImage(image, 170, 0, null);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
public static void main(String[] args) throws IOException{
Main swingControlDemo = new Main();
swingControlDemo.showEventDemo();
}
private void prepareGUI(){
mainFrame = new JFrame("Java SWING Examples");
mainFrame.setSize(400,500);
GridLayout gridlayout = new GridLayout(4, 1);
gridlayout.setVgap(1);
mainFrame.setLayout(gridlayout);
headerLabel = new JLabel("",JLabel.CENTER );
statusLabel = new JLabel("",JLabel.CENTER);
JScrollPane scroller = new JScrollPane(statusLabel, JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED, JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
mainFrame.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent windowEvent){
System.exit(0);
}
});
controlPanel = new JPanel();
controlPanel.setLayout(new FlowLayout());
image = new imagePanel();
image.setLayout(new FlowLayout());
// mainFrame.add(headerLabel);
mainFrame.add(image);
mainFrame.add(controlPanel);
mainFrame.add(scroller);
mainFrame.setVisible(true);
}
private void showEventDemo(){
headerLabel.setText("Control in action: Button");
JButton okButton = new JButton("reload");
JButton submitButton = new JButton("Submit");
JButton cancelButton = new JButton("Cancel");
okButton.setActionCommand("reload");
submitButton.setActionCommand("Submit");
cancelButton.setActionCommand("Cancel");
okButton.addActionListener(new ButtonClickListener());
submitButton.addActionListener(new ButtonClickListener());
cancelButton.addActionListener(new ButtonClickListener());
controlPanel.add(okButton);
controlPanel.add(submitButton);
//controlPanel.add(cancelButton);
controlPanel.add(textField);
System.out.println("---------------------");
mainFrame.setVisible(true);
}
private class ButtonClickListener implements ActionListener{
public void actionPerformed(ActionEvent e) {
String command = e.getActionCommand();
if( command.equals( "reload" )) {
statusLabel.setText(convertToMultiline("Line1\nLine2\nLine3\nLine4\nLine5\nLine6\nLine7\nLine8\nLine9\nLine2\nLine3\nLine\nLine2\nLine3\nLine\nLine2\nLine3\nLine\nLine2\nLine3\nLine\nLine2\nLine3\nLine\nLine2\nLine3\nLine\nLine2\nLine3\nLine"));
}
else {
statusLabel.setText("Submit Button clicked.");
}
}
}
public static String convertToMultiline(String orig)
{
return "<html>" + orig.replaceAll("\n", "<br>");
}
}
The GUI need to look like this
I want to remove the large vertical gaps between the componets, and the jLabel should use that space
Well in your comment you say you want the label to use the space. But in your picture you show the text area with all the space. How can we answer a question when you give us conflicting requirements? Be specific and accurate when describing a problem.
In any case, the default layout of a JFrame is a BorderLayout so you would probably start with that.
Then the component that you want to grow/shrink as the frame is resized should be added to the CENTER of the frame.
Then you create a second panel to contain your other components. This panel would then be added to either the PAGE_START or PAGE_NORTH of the frame depending on your exact requirement.
The layout manager of this panel can then be whatever your want. Maybe a GridLayout, or a GridBagLayout or a vertical BoxLayout.
Read the section from the Swing tutorial on Layout Managers for more information and working examples. The key point is you create nest panels each with a different layout manager to achieve your layout.
I have been trying to learn Buttons but it refuses to resize. Button1 (code below) just takes up the whole screen. I have seen other posts who's problem was that they didn't use
setMaximumSize();
but I'm using it and it still isn't working! I didn't make a JPanel yet. Here is my JFrame:
import java.awt.Dimension;
import javax.swing.JButton;
import javax.swing.JFrame;
public class Frame extends JFrame {
private JButton button1;
private JButton button2;
public Frame()
{
button1 = new JButton("Hello button1");
button2 = new JButton("Hello button2");
button2.setMaximumSize(new Dimension(100,100));
button1.setMaximumSize(new Dimension(100,100));
add(button2);
add(button1);
}
}
My main class is plain and simple:
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Panel extends JPanel{
public static void main(String args [])
{
Frame frame = new Frame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(500, 500);
frame.setVisible(true);
}
}
It's because the frame('s contentPane) has a BorderLayout by default. You add the buttons to BorderLayout.CENTER, so the layout manager ignores the minimum-, preferred- and maximumSize.
I just want them to come up small and side by side
For that you could use a simple FlowLayout. (And if you want them to be centered on the frame, a parent JPanel with a GridBagLayout)
If you want a custom width & height for the buttons, override their getPreferredSize method. Overriding this method is safer than calling setPreferredSize.
Example:
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.GridBagLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Example {
public Example() {
JButton button1 = new JButton("Hello button1");
JButton button2 = new JButton("Hello button2") {
#Override
public Dimension getPreferredSize() {
int width = super.getPreferredSize().width;
return new Dimension(width, width);
}
};;
JPanel buttonPanel = new JPanel();
buttonPanel.add(button1);
buttonPanel.add(button2);
JPanel contentPanel = new JPanel(new GridBagLayout());
contentPanel.add(buttonPanel);
JFrame frame = new JFrame();
frame.setContentPane(contentPanel);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(400, 400);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
new Example();
}
});
}
}
I added a flowlayout and changed setMaximumSize to setPreferredSize. That should fix your problem.
Here try this:
import java.awt.Dimension;
import javax.swing.JButton;
import javax.swing.JFrame;
public class Frame extends JFrame {
private JButton button1;
private JButton button2;
public Frame()
{
button1 = new JButton("Hello button1");
button2 = new JButton("Hello button2");
button2.setPreferredSize(new Dimension(100,100));
button1.setPreferredSize(new Dimension(100,100));
add(button2);
add(button1);
}
}
<----now the other class--->
import java.awt.FlowLayout;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Panel extends JPanel{
public static void main(String args [])
{
Frame frame = new Frame();
frame.setLayout(new FlowLayout());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(500, 500);
frame.setVisible(true);
}
}
I'm having trouble with this JApplet. At the moment I have a CardLayout JPanel which contains two BorderLayout JPanels. Whenever I run it, the components added to each 'card' (a JButton to go back to the other JPanel) don't display unless I use setVisible(true) for each LayoutManager. Furthermore, none of my ActionListeners work. I'm assuming because they only use show() and there's something else I have to do that's alluding me.
Must I use setVisible(true)? It seems from other questions that there's a way of doing this without that. Here's the code I'm having trouble with:
/*
*Java Version: 1.8.0_25
*Author: Peadar Ó Duinnín
*Student Number: R00095488
*/
package As1;
import java.awt.BorderLayout;
import java.awt.CardLayout;
import java.awt.Color;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JApplet;
import javax.swing.JButton;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class AUIJApplet extends JApplet implements ActionListener {
private final int WIDTH = 600;
private final int HEIGHT = 400;
private int highScore;
private int currentScore;
JPanel panelCont = new JPanel();
JPanel startPanel = new JPanel();
JPanel gamePanel = new JPanel();
JButton newGameButton = new JButton("New Game");
JButton endGameButton = new JButton("End Game");
JLabel highScoreLabel;
JLabel currentScoreLabel;
CardLayout cl = new CardLayout();
BorderLayout bl = new BorderLayout();
public AUIJApplet() {
highScore = 0;
}
#Override
public void init() {
setSize(WIDTH, HEIGHT);
panelCont.setLayout(cl);
startPanel.setLayout(bl);
gamePanel.setLayout(bl);
startPanel.add(newGameButton, BorderLayout.SOUTH);
gamePanel.add(endGameButton, BorderLayout.SOUTH);
startPanel.setBackground(Color.BLUE);
gamePanel.setBackground(Color.GREEN);
panelCont.add(startPanel, "Start Applet Screen");
panelCont.add(gamePanel, "New Game Screen");
newGameButton.addActionListener((e) -> {
newGame();
});
endGameButton.addActionListener((e) -> {
quitGame();
});
cl.show(panelCont, "Start Applet Screen");
this.add(panelCont);
}
public void newGame() {
cl.show(panelCont, "New Game Screen");
showScores(gamePanel);
}
public void quitGame() {
cl.show(panelCont, "Start Applet Screen");
if (currentScore > highScore) {
highScore = currentScore;
}
currentScore = 0;
}
public void showScores(JPanel currentPanel) {
currentPanel.add(new JLabel("High Score:") , BorderLayout.EAST);
currentPanel.add(highScoreLabel, BorderLayout.EAST);
currentPanel.add(new JLabel("Current Score:"), BorderLayout.EAST);
currentPanel.add(currentScoreLabel, BorderLayout.EAST);
}
#Override
public void actionPerformed(ActionEvent ae) {
}
}
I have made the a little similar code to perform same operation it works for me try to write the code from scratch. Here is my code.
import java.awt.BorderLayout;
import java.awt.CardLayout;
import java.awt.Color;
import java.awt.event.ActionEvent;
import javax.swing.JApplet;
import javax.swing.*;
public class Example extends JApplet {
JPanel panel1,panel2,mainPanel;
JButton start,stop;
CardLayout cl = new CardLayout();
#Override
public void init() {
panel1 = new JPanel();
panel1.setBackground(Color.red);
panel1.setLayout(new BorderLayout());
panel2 = new JPanel();
panel2.setBackground(Color.blue);
panel2.setLayout(new BorderLayout());
start = new JButton("Start");
stop = new JButton("stop");
panel1.add(start,BorderLayout.SOUTH);
panel2.add(stop,BorderLayout.SOUTH);
mainPanel = new JPanel();
mainPanel.setLayout(cl);
mainPanel.add(panel1,"First Panel");
mainPanel.add(panel2, "Second Panel");
start.addActionListener((ActionEvent e) -> {
newGame();
});
stop.addActionListener((ActionEvent e) ->{
endGame();
});
this.add(mainPanel);
}
public void newGame()
{
cl.show(mainPanel, "Second Panel");
}
public void endGame()
{
cl.show(mainPanel,"First Panel");
}
}
A while back I started a project that soon built up a shed load of code, most of the code was made up of components and their properties. All was going well until I hit an error. Off the top of head, the error was something on the line of exceeding the code limit of a constructor, roughly 65000 bytes.
This error has literally bought me and my project to halt. At the same time I have also found major problems in my understanding of SWING.
What I tried was to break my game code into logical sections, putting each section into a different class. For example, a jpanel which dealt with buying and selling would be its own .java file. Another jpanel that dealt with shipping would be in another .java file.
What I hoped to achieve was a JFrame that called each of these jpanels when the user requested it at the press of a jbutton. However, this didn't quite work as I wished, putting me in a position where I need help.
What I have done is simplified my problem by creating an example framework, hoping that somebody could point out what I need to be looking at, possibly even a solution.
I have created a JFrame which holds a panel called bg, which itself holds 2 JButtons (btn1 and btn2). In a different class file I have created a JPanel called panel1, and in another class again I have created another JPanel called panel2.
When the user opens the application they are presented with a frame and the option of two buttons, when any of these buttons are pressed I would like for either panel1 or
panel2 to open. How would this be done?
Any help would be greatly appreciated. Thanks in advance.
////////////// frame
package panel;
import java.awt.Color;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Frame implements ActionListener {
public JPanel bg;
public static JButton btn1, btn2;
public Frame(){
JFrame f = new JFrame();
f.setSize(308, 205);
f.setLayout(null);
f.setLocationRelativeTo(null);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setVisible(true);
bg = new JPanel();
bg.setSize(300, 200);
bg.setLocation(0, 0);
bg.setLayout(null);
bg.setBackground(Color.black);
bg.setVisible(true);
btn1 = new JButton("open 1");
btn1.setSize(135, 30);
btn1.setLocation(10, 10);
btn1.addActionListener(this);
btn2 = new JButton("open 2");
btn2.setSize(135, 30);
btn2.setLocation(155, 10);
btn2.addActionListener(this);
bg.add(btn1);
bg.add(btn2);
f.add(bg);
}
public static void main(String[] args) {
new Frame();
}
#Override
public void actionPerformed(ActionEvent a) {
if (a.getSource() == btn1){
}
if (a.getSource() == btn2){
}
}
}
////////////////////// panel1
package panel;
import java.awt.Color;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JPanel;
public class panel1 implements ActionListener {
public JButton btn3;
public panel1(){
JPanel a = new JPanel();
a.setSize(280, 110);
a.setLocation(155, 10);
a.setBackground(Color.red);
a.setVisible(true);
btn3 = new JButton("open bb");
btn3.setSize(100, 30);
btn3.setLocation(10, 10);
btn3.addActionListener(this);
a.add(btn3);
}
#Override
public void actionPerformed(ActionEvent a) {
if (a.getSource() == btn3){
}
}
}
//////////////////////////// panel2.java
package panel;
import java.awt.Color;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JPanel;
public class panel2 implements ActionListener {
public JButton btn4;
public panel2(){
JPanel b = new JPanel();
b.setSize(280, 110);
b.setLocation(155, 10);
b.setBackground(Color.blue);
b.setVisible(true);
btn4 = new JButton("open");
btn4.setSize(100, 30);
btn4.setLocation(10, 10);
btn4.addActionListener(this);
b.add(btn4);
}
#Override
public void actionPerformed(ActionEvent a) {
if (a.getSource() == btn4){
}
}
}
You don't need to split your panels into different classes for something this simple. Try keeping everything together:
package panel;
import java.awt.Color;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Frame implements ActionListener {
public JPanel bg,panel1,panel2;
public static JButton btn1, btn2;
public Frame(){
JFrame f = new JFrame();
f.setSize(308, 205);
f.setLayout(null);
f.setLocationRelativeTo(null);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setVisible(true);
bg = new JPanel();
bg.setSize(300, 200);
bg.setLocation(0, 0);
bg.setLayout(null);
bg.setBackground(Color.black);
bg.setVisible(true);
btn1 = new JButton("open 1");
btn1.setSize(135, 30);
btn1.setLocation(10, 10);
btn1.addActionListener(this);
btn2 = new JButton("open 2");
btn2.setSize(135, 30);
btn2.setLocation(155, 10);
btn2.addActionListener(this);
bg.add(btn1);
bg.add(btn2);
f.add(bg);
panel1 = new JPanel();
panel1.setSize(280, 110);
panel1.setLocation(155, 10);
panel1.setBackground(Color.red);
panel1.setVisible(false);
bg.add(panel1);
panel2 = new JPanel();
panel2.setSize(280, 110);
panel2.setLocation(155, 10);
panel2.setBackground(Color.blue);
panel2.setVisible(false);
bg.add(panel2);
}
public static void main(String[] args) {
new Frame();
}
#Override
public void actionPerformed(ActionEvent a) {
if (a.getSource() == btn1){
panel1.setVisible(true);panel2.setVisible(false);
}
if (a.getSource() == btn2){
panel1.setVisible(false);panel2.setVisible(true);
}
}
}
I'm currently writing an interface where a have a JFrame class and two JPanel classes. When the script is first executed, Panel A is shown. I have a JButton in Panel A which I would like, when clicked, to display Panel B instead of Panel A.
Is there any way I could do this?
Read tutorial for that.
You can use next() method of CardLayout for showing next card,
or you can use show(...); for showing specific card.
Simple example:
import java.awt.BorderLayout;
import java.awt.CardLayout;
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.JPanel;
public class Example {
public static void main(String[] args){
JFrame frame = new JFrame();
final JPanel panel = new JPanel(new CardLayout());
JLabel l1 = new JLabel("1");
JLabel l2 = new JLabel("2");
JLabel l3 = new JLabel("3");
panel.add(l1,"l1");
panel.add(l2,"l2");
panel.add(l3,"l3");
JButton btn = new JButton("next");
btn.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent arg0) {
CardLayout layout = (CardLayout) panel.getLayout();
layout.next(panel);
}
});
JButton btnSpec = new JButton("l3");
btnSpec.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent arg0) {
CardLayout layout = (CardLayout) panel.getLayout();
layout.show(panel, "l3");
}
});
frame.add(panel);
frame.add(btn,BorderLayout.SOUTH);
frame.add(btnSpec,BorderLayout.NORTH);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
}