Develop Reference

Java - Create a button from a shape

I am learning Java currently and have been given the assignmnet of finidhing off a program to create the game Conways's life (we started with some code provided to us and must add features etc to this).
I am currently stuck on a menu option for the game. I want it to start off at the menu screen, wherein buttons appear at the top for "Start", "Random", "Load", Save". I have written code so that the program displays these buttons, through a fillRect option in my paint method.
My question is, how do I use the mousePressed method to recognise the cells selected so that I can get an action to occur when they are selected. I been looking at this for a while but can't seem to get this working.
Any suggestion would be a massive help. I have shared my code below. It's a work in progress but I would really like to get this working before continuing on with the other functionality.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.awt.image.*;
public class ConwaysLife extends JFrame implements Runnable, MouseListener {
// member data
private BufferStrategy strategy;
private Graphics offscreenBuffer;
private boolean gameState[][] = new boolean[40][40];
private boolean isGameInProgress = false;
// constructor
public ConwaysLife () {
//Display the window, centred on the screen
Dimension screensize = java.awt.Toolkit.getDefaultToolkit().getScreenSize();
int x = screensize.width/2 - 400;
int y = screensize.height/2 - 400;
setBounds(x, y, 800, 800);
setVisible(true);
this.setTitle("Conway's game of life");
// initialise double-buffering
createBufferStrategy(2);
strategy = getBufferStrategy();
offscreenBuffer = strategy.getDrawGraphics();
// register the Jframe itself to receive mouse events
addMouseListener(this);
// initialise the game state
for (x=0;x<40;x++) {
for (y=0;y<40;y++) {
gameState[x][y]=false;
}
}
// create and start our animation thread
Thread t = new Thread(this);
t.start();
}
// thread's entry point
public void run() {
while ( 1==1 ) {
// 1: sleep for 1/5 sec
try {
Thread.sleep(200);
} catch (InterruptedException e) { }
// 2: animate game objects [nothing yet!]
/*if (isGameInProgress == false) {
this.repaint();
}*/
// 3: force an application repaint
this.repaint();
}
}
// mouse events which must be implemented for MouseListener
public void mousePressed(MouseEvent e) {
while (!isGameInProgress) {
int x = e.getX()/20;
int y = e.getY()/20;
if(x >= 10 && x <= 80 && y >= 40 && y <= 65) {
isGameInProgress = !isGameInProgress;
this.repaint();
}
}
// determine which cell of the gameState array was clicked on
int x = e.getX()/20;
int y = e.getY()/20;
// toggle the state of the cell
gameState[x][y] = !gameState[x][y];
// request an extra repaint, to get immediate visual feedback
this.repaint();
}
public void mouseReleased(MouseEvent e) { }
public void mouseEntered(MouseEvent e) { }
public void mouseExited(MouseEvent e) { }
public void mouseClicked(MouseEvent e) { }
//
// application's paint method
public void paint(Graphics g) {
Font font = new Font("Veranda", Font.BOLD, 20);
g = offscreenBuffer; // draw to off screen buffer
// clear the canvas with a big black rectangle
g.setColor(Color.BLACK);
g.fillRect(0, 0, 800, 800);
/*look to add a while game in progress loop here!!!*/
// draw menu options
if(!isGameInProgress) {
g.setColor(Color.green);
g.fillRect(10, 40, 70, 25);
g.fillRect(100, 40, 100, 25);
g.fillRect(300, 40, 170, 25);
g.setColor(Color.BLACK);
g.setFont(font);
g.drawString("Start", 15, 60);
g.drawString("Random", 105, 60);
g.drawString("Load", 305, 60);
g.drawString("Save", 395, 60);
}
// redraw all game objects
g.setColor(Color.WHITE);
for (int x=0;x<40;x++) {
for (int y=0;y<40;y++) {
if (gameState[x][y]) {
g.fillRect(x*20, y*20, 20, 20);
}
}
}
// flip the buffers
strategy.show();
}
// application entry point
public static void main(String[] args) {
ConwaysLife w = new ConwaysLife();
}
}

You're not going to like the answer, but it's the "correct" way to approach the problem.
What you need to understand is, Swing/AWT is using a "passive" rendering workflow and BufferStrategy is using a "active" rendering workflow, these are incompatible with each other.
As a general rule, you should not be overriding paint of top level containers like JFrame, this is going to end in no end of issues. Instead, you should be starting with something like JPanel and overriding it's paintComponent method instead.
Having said that, there's a "simpler" solution available to you. CardLayout. This will allow you to seperate the workflows of the menu from the game and resolve the issue between Swing/AWT and BufferStrategy
For example...
import java.awt.Canvas;
import java.awt.CardLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferStrategy;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
public final class Main {
public static void main(String[] args) {
new Main();
}
public Main() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
JFrame frame = new JFrame();
frame.add(new MainPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class MainPane extends JPanel {
enum View {
MENU, GAME;
}
private CardLayout cardLayout = new CardLayout();
private GamePane gamePane;
public MainPane() {
setLayout(cardLayout);
gamePane = new GamePane();
add(new MenuPane(new MenuPane.Observer() {
#Override
public void startNewGame() {
showGame();
}
#Override
public void randomGame() {
}
#Override
public void loadGame() {
}
#Override
public void saveGame() {
}
}), View.MENU);
add(gamePane, View.GAME);
}
protected void add(Component compent, View view) {
add(compent, view.name());
}
protected void showGame() {
show(View.GAME);
gamePane.start();
}
protected void showMenu() {
gamePane.stop();
show(View.MENU);
}
protected void show(View view) {
cardLayout.show(this, view.name());
}
}
public class MenuPane extends JPanel {
public interface Observer {
public void startNewGame();
public void randomGame();
public void loadGame();
public void saveGame();
}
private Observer observer;
public MenuPane(Observer observer) {
this.observer = observer;
JButton startButton = new JButton("Start");
JButton randomButton = new JButton("Random");
JButton loadButton = new JButton("Load");
JButton saveButton = new JButton("Save");
setLayout(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.ipadx = 10;
gbc.ipady = 10;
gbc.insets = new Insets(8, 8, 8, 8);
gbc.weightx = GridBagConstraints.REMAINDER;
add(startButton, gbc);
add(randomButton, gbc);
add(loadButton, gbc);
add(saveButton, gbc);
startButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
observer.startNewGame();
}
});
randomButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
observer.randomGame();
}
});
loadButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
observer.loadGame();
}
});
saveButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
observer.saveGame();
}
});
}
}
public class GamePane extends Canvas {
private Thread thread;
private volatile boolean isRunning = false;
public GamePane() {
setBackground(Color.BLACK);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(800, 800);
}
protected void start() {
if (isRunning) {
return;
}
createBufferStrategy(3);
isRunning = true;
thread = new Thread(new Runnable() {
#Override
public void run() {
mainLoop();
}
});
thread.start();
}
protected void stop() {
if (!isRunning || thread == null) {
return;
}
isRunning = false;
try {
thread.join();
} catch (InterruptedException ex) {
}
thread = null;
}
protected void mainLoop() {
try {
while (isRunning) {
render();
Thread.sleep(16);
}
} catch (InterruptedException ex) {
}
}
protected void render() {
BufferStrategy strategy = getBufferStrategy();
if (strategy == null) {
return;
}
// Render single frame
do {
// The following loop ensures that the contents of the drawing buffer
// are consistent in case the underlying surface was recreated
do {
// Get a new graphics context every time through the loop
// to make sure the strategy is validated
Graphics graphics = strategy.getDrawGraphics();
FontMetrics fm = graphics.getFontMetrics();
String text = "All your game are belong to us";
int x = (getWidth() - fm.stringWidth(text)) / 2;
int y = (getHeight() - fm.getHeight()) / 2;
graphics.setColor(Color.WHITE);
graphics.drawString(text, x, y + fm.getAscent());
// Render to graphics
// ...
// Dispose the graphics
graphics.dispose();
// Repeat the rendering if the drawing buffer contents
// were restored
} while (strategy.contentsRestored());
// Display the buffer
strategy.show();
// Repeat the rendering if the drawing buffer was lost
} while (strategy.contentsLost());
}
}
}
I would strongly recommend that you take the time to read through:
Creating a GUI With Swing
A Visual Guide to Layout Managers
Performing Custom Painting
Painting in AWT and Swing
BufferStrategy and BufferCapabilities
JavaDocs for BufferStrategy which demonstrate how the API should be used.
A "fully" BufferStrategy based approach...
Now, if you can't use Swing, "for reasons", you can still achieve a simular concept using "delegation".
Basically this means "delegating" responsibility for performing some workflow to another. In this case, we want to delegate the rendering and the handling of the mouse events.
This allows you to have a dedicated workflow for the menu and a dedicated workflow for the game, without having to try and mix a lot of state.
Why do I keep on insisting on separating these two workflows? Simply, because it makes it MUCH easier to manage and reason about, but also because it supports the Single Responsibility Principle.
The follow example makes use of Renderable interface to define the core functionality that end "render" delegate will need to implement, in this case, it's pretty simple, we want to tell the renderer to "render" it's content on each paint pass and we want to (optionally) delegate mouse clicked events (this could be done via a second interface or even just the MouseListener interface directly, but I've made it a requirement of the Renderable interface for demonstration purposes.
The "basic" solution to your actual question is found through the use of Rectangle#contains(Point).
This basically inspects each "button" Rectangle to determine if the supplied MouseEvent occurs within it's bounds, if it does, we take action.
It is, however, a little more complicated then that, as we need to have the Rectangles built ahead of time, not difficult, but it's state which is actually reliant on the parent, as we need to know the area in which the renderer is been displayed, run the example, you'll see what I mean 😉
import java.awt.Canvas;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.FontMetrics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.RenderingHints;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.geom.RoundRectangle2D;
import java.awt.image.BufferStrategy;
import javax.swing.JFrame;
public final class Main {
public static void main(String[] args) {
new Main();
}
public Main() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
MainPane mainPane = new MainPane();
JFrame frame = new JFrame();
frame.add(mainPane);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
mainPane.start();
}
});
}
public interface Renderable {
public void render(Graphics2D g2d, Dimension size);
// We could just extend from MouseListener
// but I don't need all those event handlers
public void mouseClicked(MouseEvent e);
}
public class MainPane extends Canvas {
private Thread thread;
private volatile boolean isRunning = false;
private Renderable currentRenderer;
private MenuRenderer menuRenderer;
private GameRenderer gameRenderer;
public MainPane() {
setBackground(Color.BLACK);
gameRenderer = new GameRenderer();
menuRenderer = new MenuRenderer(new MenuRenderer.Observer() {
#Override
public void startNewGame() {
showGame();
}
#Override
public void randomGame() {
}
#Override
public void loadGame() {
}
#Override
public void saveGame() {
}
});
showMenu();
addMouseListener(new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent e) {
if (currentRenderer == null) {
return;
}
currentRenderer.mouseClicked(e);
}
});
}
protected void showMenu() {
// This may need to tell the game renderer to stop
// or pause
currentRenderer = menuRenderer;
}
protected void showGame() {
currentRenderer = gameRenderer;
}
#Override
public Dimension getPreferredSize() {
return new Dimension(800, 800);
}
protected void start() {
if (isRunning) {
return;
}
createBufferStrategy(3);
isRunning = true;
thread = new Thread(new Runnable() {
#Override
public void run() {
mainLoop();
}
});
thread.start();
}
protected void stop() {
if (!isRunning || thread == null) {
return;
}
isRunning = false;
try {
thread.join();
} catch (InterruptedException ex) {
}
thread = null;
}
protected void mainLoop() {
try {
while (isRunning) {
render();
Thread.sleep(16);
}
} catch (InterruptedException ex) {
}
}
protected void render() {
BufferStrategy strategy = getBufferStrategy();
if (strategy == null && currentRenderer != null) {
return;
}
// Render single frame
do {
// The following loop ensures that the contents of the drawing buffer
// are consistent in case the underlying surface was recreated
do {
// Get a new graphics context every time through the loop
// to make sure the strategy is validated
Graphics2D g2d = (Graphics2D) strategy.getDrawGraphics();
g2d.setBackground(Color.BLACK);
g2d.fillRect(0, 0, getWidth(), getHeight());
RenderingHints hints = new RenderingHints(
RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON
);
g2d.setRenderingHints(hints);
// Render to graphics
currentRenderer.render(g2d, getSize());
// Dispose the graphics
g2d.dispose();
// Repeat the rendering if the drawing buffer contents
// were restored
} while (strategy.contentsRestored());
// Display the buffer
strategy.show();
// Repeat the rendering if the drawing buffer was lost
} while (strategy.contentsLost());
}
}
public class GameRenderer implements Renderable {
#Override
public void render(Graphics2D g2d, Dimension size) {
FontMetrics fm = g2d.getFontMetrics();
String text = "All your game are belong to us";
int x = (size.width - fm.stringWidth(text)) / 2;
int y = (size.height - fm.getHeight()) / 2;
g2d.setColor(Color.WHITE);
g2d.drawString(text, x, y + fm.getAscent());
}
#Override
public void mouseClicked(MouseEvent e) {
}
}
public class MenuRenderer implements Renderable {
public interface Observer {
public void startNewGame();
public void randomGame();
public void loadGame();
public void saveGame();
}
private Observer observer;
private String[] menuOptions = new String[]{
"New Game",
"Random",
"Load Game",
"Save Game"
};
private Rectangle[] menuBounds;
private int internalPadding = 20;
private int horizontalGap = 16;
public MenuRenderer(Observer observer) {
this.observer = observer;
}
#Override
public void render(Graphics2D g2d, Dimension size) {
if (menuBounds == null) {
createMenus(g2d, size);
}
renderMenus(g2d);
}
protected void createMenus(Graphics2D g2d, Dimension size) {
FontMetrics fm = g2d.getFontMetrics();
int totalHeight = (((fm.getHeight() + internalPadding) + horizontalGap) * menuOptions.length) - horizontalGap;
int buttonHeight = fm.getHeight() + internalPadding;
menuBounds = new Rectangle[menuOptions.length];
int buttonWidth = 0;
for (int index = 0; index < menuOptions.length; index++) {
int width = fm.stringWidth(menuOptions[index]) + internalPadding;
buttonWidth = Math.max(width, buttonWidth);
}
int yPos = (size.height - totalHeight) / 2;
for (int index = 0; index < menuOptions.length; index++) {
int xPos = (size.width - buttonWidth) / 2;
Rectangle menuRectangle = new Rectangle(xPos, yPos, buttonWidth, buttonHeight);
menuBounds[index] = menuRectangle;
yPos += buttonHeight + (horizontalGap / 2);
}
}
protected void renderMenus(Graphics2D g2d) {
for (int index = 0; index < menuOptions.length; index++) {
String text = menuOptions[index];
Rectangle bounds = menuBounds[index];
renderMenu(g2d, text, bounds);
}
}
protected void renderMenu(Graphics2D g2d, String text, Rectangle bounds) {
FontMetrics fm = g2d.getFontMetrics();
int textWidth = fm.stringWidth(text);
int textXPos = (bounds.x + (internalPadding / 2)) + ((bounds.width - internalPadding - textWidth) / 2);
int textYPos = bounds.y + (internalPadding / 2);
RoundRectangle2D buttonBackground = new RoundRectangle2D.Double(bounds.x, bounds.y, bounds.width, bounds.height, 20, 20);
g2d.setColor(Color.BLUE.darker());
g2d.fill(buttonBackground);
g2d.setColor(Color.WHITE);
g2d.drawString(text, textXPos, textYPos + fm.getAscent());
}
#Override
public void mouseClicked(MouseEvent e) {
if (menuBounds == null) {
return;
}
for (int index = 0; index < menuOptions.length; index++) {
if (menuBounds[index].contains(e.getPoint())) {
switch (index) {
case 0:
observer.startNewGame();
break;
case 2:
observer.randomGame();
break;
case 3:
observer.loadGame();
break;
case 4:
observer.saveGame();
break;
}
}
}
}
}
}

Repaint() working only half times

i've got a problem with what should be a simple excercise.
I've been asked to make an applet that prints a green oval (filled) that becomes larger until it hits the borders, than start becoming smaller.
This should go on until you close the applet.
Well, i came out with this code
import java.awt.Color;
import java.awt.Graphics;
import javax.swing.JApplet;
public class Disco extends JApplet{
private int x;
private int y;
private int r;
private boolean enlarge;
MakeLarger makeLarger;
MakeSmaller makeSmaller;
public void init() {}
public void start() {
x = getWidth()/2;
y = getHeight()/2;
r = 50;
enlarge = true;
makeLarger = new MakeLarger();
makeLarger.start();
}
public void paint(Graphics g) {
g.setColor(Color.GREEN);
g.fillOval(x - r, y- r, r*2, r*2);
}
public void update() {
if(enlarge) {
makeLarger = new MakeLarger();
makeLarger.start();
} else {
makeSmaller = new MakeSmaller();
makeSmaller.start();
}
}
private class MakeLarger extends Thread {
public void run() {
while(true) {
x = getWidth()/2;
y = getHeight()/2;
if(getWidth() > getHeight()) {
if(r < getHeight()/2) {
r++;
repaint();
try {
sleep(25);
} catch(InterruptedException e) {
e.printStackTrace();
}
} else {
enlarge = false;
update();
Thread.currentThread().interrupt();
return;
}
} else {
if(r < getWidth()/2) {
r++;
repaint();
try {
sleep(25);
} catch(InterruptedException e) {
e.printStackTrace();
}
} else {
enlarge = false;
update();
Thread.currentThread().interrupt();
return;
}
}
}
}
}
private class MakeSmaller extends Thread {
public void run() {
while(true) {
x = getWidth()/2;
y = getHeight()/2;
if(r > 50) {
r--;
repaint();
revalidate();
try {
sleep(25);
} catch(InterruptedException e) {
e.printStackTrace();
}
} else {
enlarge = true;
update();
Thread.currentThread().interrupt();
return;
}
}
}
}
}
When I start my applet the oval start growing correctly until it hits the border and then suddently stop.
The first thing i thought was that it wasn't getting smaller correctly. But a little System.out.println work showed me that all computation was going on correctly, the problem is that the applet repaint only while the makeLarger thread is active, when the makeSmaller thread is at work the call to repaint() doesn't work!
If i resize the applet window while the makeSmaller Thread is at work it repaints correctly showing me the oval getting smaller.
Can, please, someone enlight me on this odd behavior?
What am I missing?
thank you everyone for your most appreciated help and sorry if my english is so poor!

I can't say that I've looked at all the code, but a couple of suggestions:
Paint in a JPanel's paintComponent override.
This is key: call the super.paintComponent method in the override, first line. This gets rid of prior images so that the image can get smaller.
Display the JPanel within your JApplet by adding it to the applet.
Myself, I'd use a single Swing Timer for the animation loop, and would use a boolean to decide which direction the sizing should go.
But regardless of whether I were using a Swing Timer or a Runnable placed in a Thread, I'd try to keep things a simple as possible, and that would mean using a single Timer that changes direction of resizing or a single Runnable/Thread that changes size of resizing based on a boolean. This swapping of threads that you're doing just serves to overly and unnecessarily complicate things, and could quite possibly be the source of your error.
As a side recommendation, you almost never want to extend Thread. Much better is to create classes that implement Runnable, and then when you need to run them in a background thread, create a Thread, passing in your Runnable into the Thread's constructor, and then calling start() on the Thread.

First things first, thank you all for helping me!
The problem I was trying to solve was this:
Make an applet which shows a green oval getting larger until it hits the borders, then it should start getting smaller up to a fixed radius (50), then it should start over (and over) again. Solve the problem by making two threads (by extending Thread).
Just to explain why the algorithm was so odd!
Well, reading your suggestions I fixed my code, now it's running properly. Here is the code if anyone will need this.
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import javax.swing.JApplet;
import javax.swing.Timer;
public class Disco extends JApplet{
private int x;
private int y;
private int r;
private boolean enlarge;
MakeLarger makeLarger;
MakeSmaller makeSmaller;
public void init() {}
public void start() {
x = getWidth()/2;
y = getHeight()/2;
r = 50;
enlarge = true;
makeLarger = new MakeLarger();
makeLarger.start();
Timer timer = new Timer(1000/60, new ActionListener() {
public void actionPerformed(ActionEvent e) {
repaint();
}
});
timer.start();
}
public void paint(Graphics g) {
BufferedImage offScreenImage = new BufferedImage(getWidth(), getHeight(), BufferedImage.TYPE_4BYTE_ABGR_PRE);
Graphics2D g2D = (Graphics2D) offScreenImage.getGraphics();
g2D.clearRect(0, 0, getWidth(), getHeight());
g2D.setColor(Color.GREEN);
g2D.fillOval(x - r, y- r, r*2, r*2);
g.drawImage(offScreenImage, 0, 0, this);
}
public void update() {
if(enlarge) {
makeLarger = new MakeLarger();
makeLarger.start();
} else {
makeSmaller = new MakeSmaller();
makeSmaller.start();
}
}
private class MakeLarger extends Thread {
public void run() {
while(true) {
x = getWidth()/2;
y = getHeight()/2;
if(getWidth() > getHeight()) {
if(r < getHeight()/2) {
r++;
try {
sleep(25);
} catch(InterruptedException e) {
e.printStackTrace();
}
} else {
enlarge = false;
update();
Thread.currentThread().interrupt();
return;
}
} else {
if(r < getWidth()/2) {
r++;
try {
sleep(25);
} catch(InterruptedException e) {
e.printStackTrace();
}
} else {
enlarge = false;
update();
Thread.currentThread().interrupt();
return;
}
}
}
}
}
private class MakeSmaller extends Thread {
public void run() {
while(true) {
x = getWidth()/2;
y = getHeight()/2;
if(r > 50) {
r--;
try {
sleep(25);
} catch(InterruptedException e) {
e.printStackTrace();
}
} else {
enlarge = true;
update();
Thread.currentThread().interrupt();
return;
}
}
}
}
}

Java graphics - repaint an image without removing another

I am using Graphics g to draw an image for my player and a map. Whenever the player moves I want to update the player image to the new location without updating the map image. How can I do this?
Thanks in advance for any replies!
Sorry about my messy code.
Main:
package Main;
import java.awt.Dimension;
import javax.swing.JFrame;
public class Main {
public static JFrame frame;
static int size = 32;
static int width = size*20;
static int height = size*17;
static playerObj p = new playerObj(200,200);
static tileMap grid = new tileMap();
public static void main(String[] args) {
frame = new JFrame("Game");
frame.getContentPane().setPreferredSize(new Dimension(width-9, height-9));
frame.pack();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setResizable(false);
frame.add(new drawGraphics());
frame.setVisible(true);
}
}
drawGraphics:
package Main;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JPanel;
public class drawGraphics extends JPanel implements Runnable {
private static final long serialVersionUID = 1L;
boolean running = true;
boolean renderMap = true;
playerObj p = Main.p;
int size = Main.size;
static int x = 0;
static int y = 0;
Thread thread = new Thread(this);
public drawGraphics() {
setFocusable(true);
addKeyListener(new controls());
start();
}
public void start() {
thread.start();
}
public void paint(Graphics g) {
Graphics2D d = (Graphics2D) g;
super.paintComponent(g);
if (renderMap) {
map(d);
}
player(g);
repaint();
}
public void player(Graphics g) {
try {
BufferedImage pImg = ImageIO.read(new File("images/player.png"));
g.drawImage(pImg, p.getX(), p.getY(), null);
} catch (IOException e) {
e.printStackTrace();
}
}
public void map(Graphics g) {
System.out.println("2dfsdf");
Graphics2D d = (Graphics2D) g;
for (int i = 0; i < tileMap.map.length; i++) {
for (int j = 0; j < tileMap.map[i].length; j++) {
d.setColor(tileMap.map[i][j].getC());
d.fillRect(tileMap.map[i][j].getX(), tileMap.map[i][j].getY(),
Main.size, Main.size);
if (tileMap.map[i][j].solid()) {
d.setColor(Color.BLACK);
d.drawRect(tileMap.map[i][j].getX(),
tileMap.map[i][j].getY(), Main.size, Main.size);
}
}
}
}
public void move() {
if (controls.up) {
controls.goUp();
y--;
repaint();
}
if (controls.down) {
controls.goDown();
y++;
repaint();
}
if (controls.left) {
controls.goLeft();
x--;
repaint();
}
if (controls.right) {
controls.goRight();
x++;
repaint();
}
if (controls.place) {
repaint();
}
}
public void run() {
while (running == true) {
move();
try {
Thread.sleep(10);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}

Don't draw directly in a JFrame but rather in a JPanel that is displayed within the JFrame.
If you're using Swing as your GUI library, then draw the background as a BufferedImage, and draw that first in your paintComponent method. Then draw your image sprite at whatever location needed next:
#Override // this is in a JPanel extended class
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (backgroundImg != null) {
g.drawImage(backgroundImg, 0, 0, null);
}
if (spriteImg != null) {
g.drawImage(spriteImg, spriteX, spriteY, null);
}
}
Some issues with your code:
Don't override paint and then call super.paintComponent inside of it.
Instead override paintComponent and call the same super method inside.
Never call repaint() inside of paint or paintComponent. Use a Swing Timer instead.
In your player(...) method, you re-read the image in each time the method is called, something that will slow your painting down to a crawl. Don't do this, but instead read the image in once, and save it to a variable.

Image won't draw onto screen but no errors occur

I've started creating a simple java game and at the moment I have the Game Window created with a screen and a basic Player class. The player image however won't draw onto the screen despite the program not giving me any errors so I'm not sure where to start debugging for the problem maybe someone could help me out?
Here are the classes:
import java.awt.*;
import javax.swing.*;
#SuppressWarnings("serial")
public class GameWindow extends JFrame {
public static int windowWidth = 600;
public static int windowHeight = 600;
public static void main(String[] args) {
new GameWindow();
}
public GameWindow() {
this.setSize(windowWidth, windowHeight);
this.setTitle("Berzerk Clone");
this.setVisible(true);
// Defaults the window to be set in the middle of the screen
this.setLocationRelativeTo(null);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
GameDrawing drawGame = new GameDrawing();
this.add(drawGame, BorderLayout.CENTER);
}
}
Drawing Class:
import java.awt.*;
import javax.swing.*;
#SuppressWarnings("serial")
public class GameDrawing extends JComponent {
PlayerHuman p;
public GameDrawing() {
p = new PlayerHuman(300, 300);
}
public void paint(Graphics g) {
super.paint(g);
Graphics2D graphics = (Graphics2D)g;
graphics.setColor(Color.BLACK);
graphics.fillRect(0, 0, GameWindow.windowWidth,GameWindow.windowHeight);
graphics.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
graphics.drawImage(p.getPlayerImage(), 300, 300, null);
}
}
Player class:
import java.awt.*;
import java.awt.image.*;
import java.io.*;
import javax.imageio.*;
public class PlayerHuman extends GlobalPosition {
BufferedImage basicPlayer;
public PlayerHuman(int x, int y) {
super(x, y);
try {
basicPlayer = ImageIO.read(new File("Images/Player.png"));
} catch (IOException e) {
e.printStackTrace();
}
}
public void draw(Graphics2D g2d) {
g2d.drawImage(getPlayerImage(), x, y, null);
}
public BufferedImage getPlayerImage() {
return basicPlayer;
}
}
All help is appreciated.
EDIT:
My Apologies
GlobalPosition Class to give the player a starting point:
public class GlobalPosition {
public int x;
public int y;
public GlobalPosition() {
x = y = 0;
}
public GlobalPosition(int _x, int _y) {
x = _x;
y = _y;
}
public int getX() {
return x;
}
public int getY() {
return y;
}
public void setX(int newX) {
x = newX;
}
public void setY(int newY) {
y = newY;
}
}
I have a Game Loop class that repaints:
public class GameLoop implements Runnable {
GameWindow gWindow;
public GameLoop(GameWindow newGWindow) {
this.gWindow = newGWindow;
}
#Override
public void run() {
gWindow.repaint();
}
}

Suggestions:
Start small: test a very small program that does nothing but loads an image, puts it into an ImageIcon and displays the ImageIcon in a JOptionPane. Solve that first, and only then work on using it in the larger application.
You're better off reading the image in as a URL via getClass().getResource("....") than as a File.
don't call setVisible(true) on the top-level window until after adding all components.
Override the JComponent's paintComponent(Graphics g) method, not its paint method.
e.g.,
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.net.URL;
import javax.imageio.ImageIO;
import javax.swing.*;
public class ShowImage {
// ******* add the path to the image resource below *****
private static final String IMAGE_RESOURCE_PATH = "";
public static void main(String[] args) {
URL imgUrl = ShowImage.class.getResource(IMAGE_RESOURCE_PATH);
BufferedImage img;
try {
img = ImageIO.read(imgUrl);
if (img == null) {
String message = "Image cannot be found at \""
+ IMAGE_RESOURCE_PATH + "\"";
JOptionPane.showMessageDialog(null, message);
System.exit(-1);
}
Icon icon = new ImageIcon(img);
JOptionPane.showMessageDialog(null, icon);
} catch (IOException e) {
e.printStackTrace();
}
}
}

Turns out that it was the
setVisible(true)
call that was causing the problem. I pushed it below all the other calls in the method and the screen and image appeared. Thanks for the help.
EDIT:
#Sage this is the location so the location is correct, however I will begin to use the
getClass().getResource(..)
method from now on.

How do I get my image to follow my mouse?

How do I get my image to follow my mouse anywhere on the screen?
The below code makes the image move along the x axis.
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;
public class PlayerTwo implements KeyListener, MouseListener, MouseMotionListener{
public static int PLAYER_HEIGHT = 15;
public static int PLAYER_WIDTH = 15;
private Image p2Image = null;
private static int x = 0;
private static int y = 0;
private int heightPosition = 0;
Main main = null;
public PlayerTwo(Image pi, Main m ){
main = m;
p2Image = pi;
y = (int)((Main.WIDTH*2)+(PLAYER_WIDTH*2));
heightPosition = Main.HEIGHT-PLAYER_HEIGHT-20;
}
public void drawPlayer(Graphics g){
g.drawImage(p2Image, y, heightPosition, main);
}
public void keyTyped(KeyEvent e) {
}
public void keyReleased(KeyEvent e) {
}
public void mouseClicked(MouseEvent e) {
}
public void mousePressed(MouseEvent e) {
}
public void mouseReleased(MouseEvent e) {
}
public void mouseEntered(MouseEvent e) {
}
public void mouseExited(MouseEvent e) {
}
public void mouseDragged(MouseEvent e) {
}
public void mouseMoved(MouseEvent me) {
int newX = me.getX();
int newY = me.getY();
if(newY > (Main.HEIGHT+PLAYER_HEIGHT+10)){
y = Main.HEIGHT+PLAYER_HEIGHT+10;
}else{
y = newY;
}
// if (newX > (Main.WIDTH-PLAYER_WIDTH-10)){
// x = Main.WIDTH-PLAYER_WIDTH-10;
// }else{
// x = newX;
// }
}
}
Updated with Main...
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.image.BufferedImage;
import javax.swing.JFrame;
public class Main extends JFrame implements Runnable {
public static int WIDTH = 600;
public static int HEIGHT = 600;
private int gameSpeed = 100;
PlayerOne playOne = null;
PlayerTwo playTwo = null;
Image p1Image = null;
Image p2Image = null;
Image backImage = null;
Graphics offscreen_high;
BufferedImage offscreen;
public Main(String frameTitle) {
super(frameTitle);
p1Image = new javax.swing.ImageIcon("src/resources/player1.gif").getImage();
p2Image = new javax.swing.ImageIcon("src/resources/player2.gif").getImage();
backImage = new javax.swing.ImageIcon("src/resources/back.png").getImage();
offscreen = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);
offscreen_high = offscreen.createGraphics();
playOne = new PlayerOne(p1Image, this);
playTwo = new PlayerTwo(p2Image, this);
addKeyListener(playOne);
addKeyListener(playTwo);
addMouseListener(playTwo);
addMouseMotionListener(playTwo);
setSize(WIDTH, HEIGHT);
setVisible(true);
startGame();
}
public void startGame() {
Thread thread = new Thread(this);
thread.start();
}
public void paint(Graphics g) {
offscreen_high.setColor(Color.black);
offscreen_high.fillRect(0, 0, WIDTH, HEIGHT);
offscreen_high.drawImage(backImage, 0, 0, this);
playOne.drawPlayer(offscreen_high);
playTwo.drawPlayer(offscreen_high);
g.drawImage(offscreen, 0, 0, this);
}
// public void update(Graphics g){
// paint(g);
// }
public void run() {
int count = 0;
while (true) {
try {
Thread.sleep(gameSpeed);
} catch (InterruptedException ie) {
}
repaint();
count++;
}
}
public static void main(String[] args) {
Main main = new Main("Game On!");
}
}

Generally, you need some way to tell the UI that it should be updated.
Assuming that Main is some kind of component (and it's also responsible for painting the Player), you should be calling its repaint method in the mouseListener
But without more details, this is more of a guess
Updated
After a muck around with the code, the main problem, as I see it, is your trying to draw the image only the horizontal axis (x) using the vertical position (y)...
public void drawPlayer(Graphics g){
//g.drawImage(p2Image, y, heightPosition, main);
g.drawImage(p2Image, x, heightPosition, main);
}
To get it to work, you're going to have to uncomment the code in you mouseMoved method so that the x position updates.
You should also avoid painting to top level containers, the main reason (apart from the fact that you can screw up the paint process) is that top level containers are not double buffered.
Instead, you should move your entire game container over to something like a JPanel and override it's paintComponent method (and don't for get to call super.paintComponent)