I'm trying to create simple Pong game.
The first thing I'm working on is getting a paddle to move left or right when the user clicks the "Left" or "Right" button provided in the frame.
When the user clicks a button, an action listener in the MainPanel class changes the constant in the Paddle class called "paddlePosition" and then calls "repaint()".
However, it's not working, and the paddle is not moving. I know the buttons are working because it outputs "Hello World" and the value of paddlePosition but apparently something is wrong with the repaint.
I'm using Swing, JFrame, and Graphics2D to get everything working so far.
MY CLASSES:
Pong Frame (run class)
import java.awt.BorderLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
public class PongFrame extends JFrame{
private static final long serialVersionUID = 1L;
public PongFrame(){
ButtonPanel buttonPanel = new ButtonPanel();
MainPanel mainPanel = new MainPanel();
add(buttonPanel, BorderLayout.SOUTH);
add(mainPanel);
setSize(400, 400);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setLocationRelativeTo(null);
setVisible(true);
}
public static void main(String[] args) {
new PongFrame();
}
}
Main Panel:
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JPanel;
import javax.swing.JTextField;
public class MainPanel extends JPanel implements ActionListener{
public Paddle paddle;
public MainPanel(){
setSize(300, 300);
paddle = new Paddle();
}
public void paint(Graphics g) {
super.paint(g);
Graphics2D g2 = (Graphics2D)g;
paddle.draw(g2);
}
public void actionPerformed(ActionEvent e) {
System.out.println("Hello World");
Paddle.movePaddleLeft();
System.out.println(Paddle.paddlePosition);
this.repaint();
}
}
Button Panel:
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JPanel;
public class ButtonPanel extends JPanel {
private static final long serialVersionUID = 1L;
public MainPanel mainPanelActionListener = new MainPanel();
JButton left;
JButton right;
public ButtonPanel(){
left = new JButton("Left");
right = new JButton("Right");
add(left);
add(right);
left.addActionListener(mainPanelActionListener);
right.addActionListener(mainPanelActionListener);
}
}
Paddle:
import java.awt.Graphics2D;
public class Paddle{
public static int paddlePosition = 200;
private java.awt.Rectangle paddle;
private int centerCoordinateX;
private int centerCoordinateY;
public Paddle(){
//paddle = new java.awt.Rectangle(paddlePosition, 285, 100, 10); // x, y, width, height
}
public void draw(Graphics2D g2){
paddle = new java.awt.Rectangle(paddlePosition, 285, 100, 10);
g2.draw(paddle);
}
public static void movePaddleLeft(){
paddlePosition = (paddlePosition + 3);
}
}
Does anyone see what is wrong? Why won't the paddle move when the buttons are clicked?
In the ButtonPanel you're creating a new MainPanel. This causes you to create a new invisible panel that you're updating.
What you actually need to do, is send the MainPanel to your ButtonPanel in it's constructor.
Edit: (disclaimer: all code here is generated without an IDE)
In the PongFrame constructor do the following:
MainPanel mainPanel = new MainPanel();
ButtonPanel buttonPanel = new ButtonPanel(mainPanel);
This creates a ButtonPanel with a reference to the MainPanel.
Now for the ButtonPanel:
public MainPanel mainPanelReference;
JButton left;
JButton right;
public ButtonPanel(MainPanel mainPanelReference) {
this.left = new JButton("Left");
this.right = new JButton("Right");
add(left);
add(right);
this.mainPanelReference = mainPanelReference;
left.addActionListener(mainPanelReference);
right.addActionListener(mainPanelReference);
}
Related
I'm trying to set the size and location of a button on a panel using setBounds. It works when I put the button on the frame and have setLayout(null). But when placed on the panel, the button is always a set size at the top of the panel, if I set the layout to null, the frame just shows up blank.
import javax.swing.JFrame;
import javax.swing.*;
public class Main {
public static void main(String[] args) {
MyFrame cl=new MyFrame("A");
cl.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class MyFrame extends JFrame implements ActionListener{
MyPanel panel;
Container cont;
JButton b;
public MyFrame(String title) {
super(title);
panel= new MyPanel();
b = new JButton();
b.setBounds(100, 100, 100, 100 );
cont= this.getContentPane();
cont.setLayout(new BorderLayout());
cont.add(panel, BorderLayout.CENTER);
panel.add(b);
this.setLayout(null);
this.setVisible(true);
this.setSize(1000,1000);
}
}
import java.awt.Color;
import java.awt.Graphics;
import javax.swing.JPanel;
public class MyPanel extends JPanel {
public MyPanel() {
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
this.setBackground(Color.BLACK);
}
}
I need to calculate window decorations somehow. So I override JDialog's constructor. But when I call get_decoration_size() it sometimes returns wrong values. And my thought was: window creates later than get_decoration_size() executes(strange, because both in same thread and in same constructor). So I decided to sleep for a second, and it worked, and now decorations always valid.
My question is: is there a way to "join" to the creating process(wait until window is shown by setVisible(true))? If so, it must be something to replace unsafe_sleep(1000).
package swing.window;
import db.db;
import javax.swing.*;
import java.awt.*;
import static swing.util.*;
import static util.util.unsafe_sleep;
public class calc_decor extends JDialog {
{
//some initializations
setLayout(null);
setResizable(false);
JLabel label = new JLabel("Loading...");
add(label);
setxy(label, 3, 3);
fit(label);
setsize(this, label.getWidth() + 100, label.getHeight() + 100);
window_to_center(this);
setVisible(true);//trying to draw
unsafe_sleep(1000);//without that it looks like get_decoratoin_size()
//is called before setVisible(true)
db.sysdecor = get_decoration_size();//trying to get decorations
dispose();
}
private Dimension get_decoration_size() {
Rectangle window = getBounds();
Rectangle content = getContentPane().getBounds();
int width = window.width - content.width;
int height = window.height - content.height;
return new Dimension(width, height);
}
}
I had to assume a lot to create a runnable example.
Here's the result of your getDecorationSize method. The line didn't print until I closed the JDialog.
java.awt.Dimension[width=16,height=39]
And here's the code I used.
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.Rectangle;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class JDialogTest implements Runnable {
public static void main(String[] args) {
SwingUtilities.invokeLater(new JDialogTest());
}
private JFrame frame;
#Override
public void run() {
frame = new JFrame("JDialog Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(createMainPanel());
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
private JPanel createMainPanel() {
JPanel panel = new JPanel(new BorderLayout());
panel.setBorder(BorderFactory.createEmptyBorder(
150, 100, 150, 100));
panel.setPreferredSize(new Dimension(400, 400));
JButton button = new JButton("Open JDialog");
button.addActionListener(new ButtonListener());
panel.add(button);
return panel;
}
public class ButtonListener implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
new CalculateDecor(frame, "Spash Screen");
}
}
public class CalculateDecor extends JDialog {
private static final long serialVersionUID = 1L;
public CalculateDecor(JFrame frame, String title) {
super(frame, true);
setDefaultCloseOperation(DISPOSE_ON_CLOSE);
setTitle(title);
JPanel panel = new JPanel(new BorderLayout());
panel.setPreferredSize(new Dimension(200, 200));
JLabel label = new JLabel("Loading...");
label.setHorizontalAlignment(JLabel.CENTER);
panel.add(label);
add(panel);
pack();
setLocationRelativeTo(frame);
setVisible(true);
System.out.println(getDecorationSize());
}
private Dimension getDecorationSize() {
Rectangle window = getBounds();
Rectangle content = getContentPane().getBounds();
int width = window.width - content.width;
int height = window.height - content.height;
return new Dimension(width, height);
}
}
}
I am trying to create a GUI that will take in the number of circles to draw, and draw them in drawPanel with random locations/sizes. On my actionListener, when I try to draw the circle, it gives me red lines on my drawOval
1st class:
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Random;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JPanel;
import javax.swing.JTextArea;
/**
*
* #author Chris
*
*/
public class CirclesPanel extends JPanel{
private JButton draw, clear;
private JTextArea textArea;
private JPanel panel, drawPanel, buttonPanel;
private int count;
/**constructor
* builds the frame
*/
public CirclesPanel(){
//creates buttons and textArea
draw = new JButton("Draw");
clear = new JButton("Clear");
textArea = new JTextArea(1,10);
textArea.setBorder(BorderFactory.createTitledBorder("Circles"));
//creats panel
JPanel panel = new JPanel();
panel.setLayout(new BorderLayout());
setPreferredSize(new Dimension(620, 425));
//creates subpanel drawPanel
JPanel drawPanel = new JPanel();
drawPanel.setPreferredSize(new Dimension(450,400));
drawPanel.setBackground(Color.BLACK);
//creates subpanel buttonPanel
JPanel buttonPanel = new JPanel();
buttonPanel.setLayout(new GridLayout(3,1));
//adds all the content to the frame
add(panel);
add(buttonPanel, BorderLayout.WEST);
add(drawPanel, BorderLayout.EAST);
buttonPanel.add(textArea);
buttonPanel.add(draw);
buttonPanel.add(clear);
//reads if the draw button is clicked
draw.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e)
{
count =Integer.parseInt(textArea.getText());//takes the count in
repaint();//repaints the picture to add the circles
}
});
//reads if the clear button is clicked
clear.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e)
{
count=0;//sets the count to 0 so nothing is painted
repaint();//repaints the window
}
});
}
/**Paint component
* draws the random circles
*/
public void paintComponent(Graphics g) {
Random generator = new Random();
int x, y, diameter;
for(int i = 0; i < count; i++){ //loop that takes the count and does this "x" times
g.setColor(Color.BLUE);//sets color to blue
x = generator.nextInt(90);//random location for x
y = generator.nextInt(90);//random location for y
diameter = generator.nextInt(30);//random size
g.fillOval(x, y, diameter, diameter);//draws the circle
}
}
}
2nd class
import javax.swing.JFrame;
public class Circles {
public static void main(String[]args){
JFrame frame = new JFrame("Cicles HW9");
frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new CirclesPanel());
frame.pack();
frame.setVisible(true);
}
}
So in your, I did little addition, first of all, I made the whole program in one class(CIRLCES PANEL), IF You want to use the second class, you can use it....
Problem is coming, your program is not the reading the ActionPerformed method for the drawing, means it is not located with the button, now I directly added it with your button(DRAW), now whenever you click on the button, it automatically reads the your textArea value, and draw your circles. I made your text area FINAL, So you can use it anywhere......
Now things that you need to do----
- this program is drawing circle on the whole frame, means not on your drawing Panel, you need to set the values, so it will draw on your draw panel area
- Also you need to add color for your oval, because it will either draw black color circle, which you will not able to see.....
and also one thing I forget to mentioned you, is that your, you also need to add code for your clear method...
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Random;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JPanel;
import javax.swing.JTextArea;
public class CirclesPanel extends JPanel{
private JButton draw, clear;
private JTextArea textArea;
private JPanel panel, drawPanel, buttonPanel;
private int count;
public CirclesPanel(){
JButton draw = new JButton("Draw");
JButton clear = new JButton("Clear");
final JTextArea textArea = new JTextArea(1,10);
textArea.setBorder(BorderFactory.createTitledBorder("Circles"));
JPanel panel = new JPanel();
panel.setLayout(new BorderLayout());
setPreferredSize(new Dimension(620, 425));
JPanel drawPanel = new JPanel();
drawPanel.setPreferredSize(new Dimension(450,400));
drawPanel.setBackground(Color.BLACK);
JPanel buttonPanel = new JPanel();
buttonPanel.setLayout(new GridLayout(3,1));
add(panel);
add(buttonPanel, BorderLayout.WEST);
add(drawPanel, BorderLayout.EAST);
buttonPanel.add(textArea);
buttonPanel.add(draw);
buttonPanel.add(clear);
draw.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e)
{
count =Integer.parseInt(textArea.getText());
repaint();
}
});
}
public void paintComponent(Graphics g) {
Random generator = new Random();
int x, y, diameter;
for(int i = 0; i < count; i++){
x = generator.nextInt(90);
y = generator.nextInt(90);
diameter = generator.nextInt(30);
g.drawOval(x, y, diameter, diameter);
}
}
}
What you want to do is drawing some random circles on the drawPanel when button clicked. I write you a simplified version to show how things work.
I only keep the drawButton and paintPanel to keep things simple.
public class PaintFrame extends JFrame {
private JPanel content = new JPanel();
private JButton drawButton = new JButton("Draw");
private PaintPanel paintPanel = new PaintPanel();
public PaintFrame() {
getContentPane().add(content);
content.setLayout(new BorderLayout());
drawButton.setSize(100, 500);
drawButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
// drawButton is fired, repaint the paintPanel
paintPanel.repaint();
}
});
content.add(drawButton, BorderLayout.WEST);
content.add(paintPanel, BorderLayout.CENTER);
}
}
You need a new class extending the JPanel and override the paintComponent method to do the paint job for you. This makes sure you are drawing on the panel.
class PaintPanel extends JPanel {
public PaintPanel() {
setSize(500, 500);
setBackground(Color.BLACK);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Random random = new Random();
g.setColor(Color.WHITE);
// draw 5 random circles
int count = 5;
for (int i = 0; i < count; i++) {
g.drawOval(random.nextInt(250), random.nextInt(250),
random.nextInt(250), random.nextInt(250));
}
}
}
Main class
public class DrawMain {
public static void main(String[] args) {
JFrame frame = new PaintFrame();
frame.setDefaultCloseOperation(PaintFrame.EXIT_ON_CLOSE);
frame.setSize(600, 500);
frame.setVisible(true);
}
}
So I have this problem with my code. Whenever I load up the game there is a red square in the center of the screen, and I have not programmed it to do so. I have tried to find the error for hours but I just can't see it. I think it has to do with the panels or something. The second thing is that when I press the button to draw the grid, only a small line appears. It is programmed to be much bigger than what it is, and it is not in the right location either. Below is all my code, and any help is greatly appreciated!!
package com.theDevCorner;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JMenuBar;
import javax.swing.JPanel;
public class Game extends JPanel implements ActionListener {
public static JButton grid = new JButton("Show Grid");
public static JPanel drawArea = new JPanel();
public static JMenuBar menu = new JMenuBar();
public static JPanel notDrawn = new JPanel();
public static boolean gridPressed = false;
public Game() {
grid.addActionListener(this);
}
public static void main(String args[]) {
Game game = new Game();
JFrame frame = new JFrame();
frame.setVisible(true);
frame.setSize(new Dimension(
Toolkit.getDefaultToolkit().getScreenSize().width, Toolkit
.getDefaultToolkit().getScreenSize().height));
frame.setTitle("Game");
frame.setAlwaysOnTop(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setResizable(false);
menu.setSize(new Dimension(1600, 20));
menu.setLocation(0, 0);
notDrawn.setBackground(new Color(255, 0, 50));
notDrawn.setSize(100, 900);
notDrawn.add(grid);
notDrawn.setLayout(null);
grid.setSize(new Dimension(100, 25));
grid.setLocation(0, 25);
drawArea.setSize(new Dimension((Toolkit.getDefaultToolkit()
.getScreenSize().width), Toolkit.getDefaultToolkit()
.getScreenSize().height));
drawArea.setLocation(100, 0);
drawArea.setBackground(Color.black);
drawArea.add(menu);
drawArea.add(game);
frame.add(drawArea);
frame.add(notDrawn);
}
public void paint(Graphics g) {
Game game = new Game();
if (gridPressed) {
Game.drawGrid(0, 0, g);
}
g.dispose();
repaint();
}
public static void drawGrid(int x, int y, Graphics g) {
g.setColor(Color.white);
g.drawLine(x, y, 50, 300);
}
#Override
public void actionPerformed(ActionEvent e) {
if (e.getSource() == grid && gridPressed == true) {
gridPressed = false;
System.out.println("Unpressed");
}
if (e.getSource() == grid) {
gridPressed = true;
System.out.println("Pressed");
}
}
}
There are a number of problems...
The red "square" you are seeing is actually your grid button. The reason it's red is because of your paint method.
Graphics is a shared resource, that is, each component that is painted on the screen shares the same Graphics context. Because you chose to dispose of the context and because you've failed to honor the paint chain, you've basically screwed it up.
Don't EVER dispose of a Graphics context you didn't create. It will prevent anything from being painted to it again. Always call super.paintXxx. The paint chain is complex and does a lot of very important work. If you're going to ignore it, be ready to have to re-implement it.
null layouts are vary rarely the right choice, especially when you're laying out components. You need to separate your components from your custom painting, otherwise the components will appear above the custom painting.
This frame.setSize(new Dimension(Toolkit.getDefaultToolkit().getScreenSize().width, Toolkit.getDefaultToolkit().getScreenSize().height)) is not the way to maximize a window. This does not take into consideration the possibility of things like tasks bars. Instead use Frame#setExtendedState
As Andreas has already commented, you actionPerformed logic is wrong. You should be using an if-statement or simply flipping the boolean logic...
Updated with simple example
ps- static is not your friend here...
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Game extends JPanel implements ActionListener {
private GridPane gridPane;
public Game() {
setLayout(new BorderLayout());
SideBarPane sideBar = new SideBarPane();
sideBar.addActionListener(this);
add(sideBar, BorderLayout.WEST);
gridPane = new GridPane();
add(gridPane);
}
public static void main(String args[]) {
Game game = new Game();
JFrame frame = new JFrame();
frame.setVisible(true);
frame.setExtendedState(JFrame.MAXIMIZED_BOTH);
frame.setTitle("Game");
frame.setAlwaysOnTop(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(game);
}
#Override
public void actionPerformed(ActionEvent e) {
if (e.getActionCommand().equalsIgnoreCase("grid")) {
gridPane.setGridOn(!gridPane.isGridOn());
}
}
public class GridPane extends JPanel {
private boolean gridOn = false;
public GridPane() {
setBackground(Color.BLACK);
}
public boolean isGridOn() {
return gridOn;
}
public void setGridOn(boolean value) {
if (value != gridOn) {
this.gridOn = value;
repaint();
}
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (gridOn) {
g.setColor(Color.white);
g.drawLine(0, 0, 50, 300);
}
}
}
public class SideBarPane extends JPanel {
public JButton grid;
public SideBarPane() {
setBackground(new Color(255, 0, 50));
setLayout(new GridBagLayout());
grid = new JButton("Show Grid");
grid.setActionCommand("grid");
GridBagConstraints gbc = new GridBagConstraints();
gbc.anchor = GridBagConstraints.NORTH;
gbc.weighty = 1;
add(grid, gbc);
}
public void addActionListener(ActionListener listener) {
grid.addActionListener(listener);
}
}
}
I am making a simple game using a JFrame. I have made a simple "Start" screen which basically consists of a String and a JButton. I am picking up the button click with the actionPerformed(ActionEvent e) method. I don't know how to change the cards using a button click. This may seem like a simple problem to solve, but the twist comes with this: My main JFrame, my StartScreen and my JPanel where the game takes place are all in separate files. My main file, Virus.java, is where I create the JFrame. My file VirusGamePanel.java is where the game takes place. My file StartScreen.java is the screen with the button. I want to change 'cards' to the game screen when the player clicks the button. How can I do this?
My StartScreen.java file:
package virus;
import javax.swing.JPanel;
import java.awt.event.ActionListener;
import java.awt.Graphics;
import java.awt.Font;
import java.awt.Color;
import javax.swing.JButton;
import java.awt.Rectangle;
import java.awt.event.ActionEvent;
import java.awt.CardLayout;
public class StartScreen extends JPanel implements ActionListener{
private static final long serialVersionUID = 1L;
JButton start = new JButton("Start");
public StartScreen(){
start.addActionListener(this);
start.setBounds(new Rectangle(400,300,100,30));
this.add(start);
}
public void paint(Graphics g){
super.paint(g);
g.setFont(new Font("Impact",Font.BOLD,72));
g.setColor(Color.MAGENTA);
g.drawString("Virus",275,300);
}
public void actionPerformed(ActionEvent e)
{
if(e.getSource()==start)
{
//what to do here?
}
}
}
My Virus.java file:
package virus;
import javax.swing.*;
import java.awt.CardLayout;
import virus.StartScreen;
public class Virus extends JFrame{
private static final long serialVersionUID =1L;
JFrame jf = new JFrame("Virus");
static JPanel thegame = new JPanel(new CardLayout());
JPanel game = new VirusGamePanel();
JPanel start = new StartScreen();
public Virus(){
jf.setResizable(false);
jf.setSize(600,600);
jf.setLocationRelativeTo(null);
jf.setDefaultCloseOperation(EXIT_ON_CLOSE);
jf.setVisible(true);
jf.add(thegame);
thegame.add(start);
thegame.add(game);
}
public static void main(String[] args) {
new Virus();
}
}
You simply have to right this in your actionPerformed(...) method :
public void actionPerformed(ActionEvent e)
{
if(e.getSource()==start)
{
//what to do here?
CardLayout cardLayout = (CardLayout) Virus.thegame.getLayout();
cardLayout.next(Virus.thegame);
}
}
As very much pointed out by #kleopatra (THE EMPRESS) herself, don't override paint() instead do your painting stuff inside paintComponent(Graphics g) method of any JPanel/JComponent. Moreover, first add the components to your JFrame, once it's size is realized, then only set it to Visible, not before that. Instead of setting sizes for the JFrame simply override the JPanel's method getPreferredSize(), make it return some valid Dimension Object.
Do watch this sequence, as you write your code the next time :
public Virus(){
jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
jf.setResizable(false);
thegame.add(start);
thegame.add(game);
jf.add(thegame);
jf.pack();
jf.setLocationRelativeTo(null);
jf.setVisible(true);
}
Here is your full code :
import javax.swing.JFrame;
import javax.swing.JPanel;
import java.awt.event.ActionListener;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Font;
import java.awt.Color;
import javax.swing.JButton;
import javax.swing.JLabel;
import java.awt.Rectangle;
import java.awt.event.ActionEvent;
import java.awt.CardLayout;
public class Virus extends JFrame{
private static final long serialVersionUID =1L;
JFrame jf = new JFrame("Virus");
static JPanel thegame = new JPanel(new CardLayout());
JPanel game = new VirusGamePanel();
JPanel start = new StartScreen();
public Virus(){
jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
jf.setResizable(false);
thegame.add(start);
thegame.add(game);
jf.add(thegame);
jf.pack();
jf.setLocationRelativeTo(null);
jf.setVisible(true);
}
public static void main(String[] args) {
new Virus();
}
}
class StartScreen extends JPanel implements ActionListener{
private static final long serialVersionUID = 1L;
JButton start = new JButton("Start");
public StartScreen(){
start.addActionListener(this);
start.setBounds(new Rectangle(400,300,100,30));
this.add(start);
}
#Override
protected void paintComponent(Graphics g){
super.paintComponent(g);
g.setFont(new Font("Impact",Font.BOLD,72));
g.setColor(Color.MAGENTA);
g.drawString("Virus",275,300);
}
#Override
public Dimension getPreferredSize()
{
return (new Dimension(600, 600));
}
public void actionPerformed(ActionEvent e)
{
if(e.getSource()==start)
{
//what to do here?
CardLayout cardLayout = (CardLayout) Virus.thegame.getLayout();
cardLayout.next(Virus.thegame);
}
}
}
class VirusGamePanel extends JPanel
{
public VirusGamePanel()
{
JLabel label = new JLabel("I am ON", JLabel.CENTER);
add(label);
}
#Override
public Dimension getPreferredSize()
{
return (new Dimension(600, 600));
}
}
Your StartScreen class has to have access to the instance of the CardLayout of the JFrame and the instance of the VirusGamePanel class. You can pass these instances in the constructor or a setLayout method and setVirusGamePanel method of your StartScreen class.
Something like:
layout.next(virusGamePanel);
should work.