I have made simple JFrame that works fine except when I am trying to access it from other classes it returns null. So I made getter for it (public static JFrame getWindow()) it returns null. If I set JFrame to public and try to access it that way it returns null. When I create it becomes null right after the game engine starts.
Main:
public class Main {
private static String title = "2D SquareWorld 0.";
private static String version = "";
private static JFrame window;
private static Container container;
public static void main(String[] args) {
GameEngine game = new GameEngine();
window = new JFrame();
window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
window.setTitle(title + Version.newVersion());
window.setResizable(false);
window.add(game);
window.setSize(1000, 720);
window.setLocationRelativeTo(null);
window.setVisible(true);
game.start();
}
public static Container getContainer() {
return container;
}
public static JFrame getWindow() {
return window;
}
}
GameEngine:
package GameEngine;
public class GameEngine extends Canvas implements Runnable, KeyListener, MouseListener, MouseMotionListener {
private static final long serialVersionUID = 1L;
private Thread thread;
private boolean running;
private GameStateManager gsm;
public GameEngine() {
gsm = new GameStateManager();
}
public void start() {
thread = new Thread(this, "Game");
thread.start();
running = true;
init();
}
public void init() {
Data.setValue("ScreenWidth", getWidth());
Data.setValue("ScreenHeight", getHeight());
addKeyListener(this);
}
public void update(double delta) {
}
public void render() {
BufferStrategy bs = getBufferStrategy();
if(bs == null) {
createBufferStrategy(2);
return;
}
Graphics g = bs.getDrawGraphics();
Graphics2D g2 = (Graphics2D) g;
g2.setColor(Color.white);
g2.fillRect(0, 0, getWidth(), getHeight());
gsm.draw(g2);
g2.dispose();
bs.show();
}
public void run() {
long lastLoopTime = System.nanoTime();
long lastFpsTime = 0;
final int TARGET_FPS = Fps.TargetFPS;
final long OPTIMAL_TIME = 1000000000 / TARGET_FPS;
int CurrentFps = 0;
while(running) {
long now = System.nanoTime();
long updateLength = now - lastLoopTime;
lastLoopTime = now;
double delta = updateLength / ((double) OPTIMAL_TIME);
lastFpsTime += updateLength;
CurrentFps++;
if (lastFpsTime >= 1000000000) {
Fps.FPS = CurrentFps;
lastFpsTime = 0;
CurrentFps = 0;
}
update(delta);
render();
try {
if(((lastLoopTime-System.nanoTime() + OPTIMAL_TIME) / 1000000) >= 1) {
Thread.sleep((lastLoopTime-System.nanoTime() + OPTIMAL_TIME) / 1000000);
}
}catch(InterruptedException IE) {
}
}
}
public void mouseDragged(MouseEvent me) {
}
public void mouseMoved(MouseEvent me) {
}
public void mouseClicked(MouseEvent me) {
}
public void mouseEntered(MouseEvent me) {
}
public void mouseExited(MouseEvent me) {
}
public void mousePressed(MouseEvent me) {
}
public void mouseReleased(MouseEvent me) {
}
public void keyPressed(KeyEvent ke) {
gsm.keyPressed(ke.getKeyCode());
}
public void keyReleased(KeyEvent ke) {
}
public void keyTyped(KeyEvent ke) {
}
}
I called getWindow from this class:
public class LoginState extends GameState {
private GameStateManager gsm;
public LoginState(GameStateManager gsm) {
this.gsm = gsm;
}
private JTextField username;
private JTextField password;
public void init() {
username = new JTextField(25);
username.setVisible(true);
username.setBounds(20, 20, 50, 50);
Main.getWindow().add(username);
}
public void draw(Graphics2D g) {
g.setColor(Color.gray);
//g.fillRect(0, 0, Data.getIntegerValue("ScreenWidth"), Data.getIntegerValue("ScreenHeight"));
}
GameStateManager:
public class GameStateManager {
private ArrayList<GameState> gameStates;
public static final int LOGINSTATE = 0;
public static final int MENUSTATE = 1;
public static final int PLAYSTATE = 2;
private static int currentState;
public GameStateManager() {
gameStates = new ArrayList<GameState>();
currentState = LOGINSTATE;
gameStates.add(new LoginState(this));
gameStates.add(new MenuState(this));
gameStates.add(new PlayState(this));
gameStates.get(currentState).init();
}
Please help.
Thanks for the update, but... you still haven't shown where LoginWindow is being initialized.
A guess -- you're program is starting from a different main method from the one you're showing, and so the main method which creates and assigns your JFrame to the static window field is never called. I suggest that you avoid using static methods and fields in this way, that depend on a main method to initialize. Java is an OOP language -- so make your code OOP compliant and create needed objects within code guaranteed to be called, and then assign them to non-static fields.
edit:
simply swap the two lines:
GameEngine game = new GameEngine();
window = new JFrame();
to
window = new JFrame();
GameEngine game = new GameEngine();
Your JFrame gets initialized in the main method of Main. You are better off using a static initialization block instead.
static {
window = new JFrame();
window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
window.setTitle(title + Version.newVersion());
window.setResizable(false);
window.add(game);
window.setSize(1000, 720);
window.setLocationRelativeTo(null);
window.setVisible(true);
}
Related
I decided I wanted to experiment with making a game and I like Java, so I started following a tutorial here. I did deviate from the video a few times when I felt it was cleaner while being synonymous with the tutorial's code, but not in any way I thought would affect how the code worked. For example, it made sense to me that there should only ever be one instance of the Renderer, and Object Registry so I made them Singletons.
The code I have so far is supposed to create a window with a black background, and a blue square in the middle of the window representing the player, that much is working. However, it should also be sliding around in response to the wasd keys, and even more slowly drifting in one direction regardless. Instead it's doing nothing.
I spent no less than an hour trying to figure out why it wasn't working. It seems to be ticking just fine and the data looks like it's updating properly, but even though my render methods are also being called, the screen just isn't changing.
This is all the code I have so far, since I'm out of ideas as to the problem. I apologize for listing a whole project.
public class Game implements Runnable {
private final Thread thread;
private boolean running = false;
Game() {
thread = new Thread(this);
}
public static void main(String[] args) {
Game game = new Game();
game.start();
new Player(600,450,0));
}
private void start() {
thread.start();
running = true;
}
#Override
public void run() {
double tps = 10.0;
double nsPerTick = 1000000000 / tps;
double delta = 0;
int frames = 0;
long timer = System.currentTimeMillis();
long lTime = System.nanoTime();
long now;
while (running) {
now = System.nanoTime();
delta += (now - lTime) / nsPerTick;
lTime = now;
while (delta >= 1) {
Registry.getInstance().tick();
delta--;
}
if (running) Renderer.getInstance().run();
frames++;
if (System.currentTimeMillis() - timer > 1000) {
timer += 1000;
System.out.println("FPS: " + frames);
frames = 0;
}
}
stop();
}
private void stop() {
try {
thread.join();
} catch (Exception e) {
e.printStackTrace();
}
running = false;
}
}
public class Renderer extends Canvas {
private static final Renderer renderer = new Renderer();
private final Window window;
private final BufferStrategy bs;
private final Graphics g;
boolean black = true;
private Renderer() {
window = new Window(1200, 900, "First Game", this);
this.createBufferStrategy(2);
bs = this.getBufferStrategy();
g = bs.getDrawGraphics();
addKeyListener(Controller.getInstance());
}
public static Renderer getInstance() {return renderer;}
public void run() {
g.setColor(Color.BLACK);
//this was to see if even the background would update, it wouldn't
//g.setColor(black ? Color.BLACK : Color.WHITE);
//black = !black;
g.fillRect(0,0,1200, 900);
Registry.getInstance().render();
g.dispose();
bs.show();
}
public Graphics getGraphics() {return g;}
private static class Window extends Canvas {
private Window(int width, int height, String title, Renderer renderer) {
JFrame frame = new JFrame(title);
frame.setPreferredSize(new Dimension(width, height));
frame.setMinimumSize(new Dimension(width, height));
frame.setMaximumSize(new Dimension(width, height));
frame.setResizable(false);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null);
frame.add(renderer);
frame.setVisible(true);
}
}
}
public class Registry {
private static final Registry reg = new Registry();
private final LinkedList<GameObject> objects = new LinkedList<>();
private Registry() {
}
public static Registry getInstance() { return reg; }
public void tick() { //System.out.println("tick");
objects.forEach(GameObject::tick); }
public void render() { objects.forEach(GameObject::render); }
public void add(GameObject gameObject) { objects.add(gameObject); }
public void remove(GameObject gameObject) { objects.remove(gameObject);}
}
public class Controller extends KeyAdapter {
private static final Controller controller = new Controller();
private final HashMap<Character,Boolean> keyStates = new HashMap<>();
private Controller() {
}
public static Controller getInstance() {
return controller;
}
public void keyPressed(KeyEvent e) {
if (!keyStates.getOrDefault(e.getKeyChar(), true)) System.out.println(e.getKeyChar() + " down");
keyStates.put(e.getKeyChar(),true);
}
public void keyReleased(KeyEvent e) {
keyStates.put(e.getKeyChar(),false);
System.out.println(e.getKeyChar() + " up " + keyStates.size());
}
public boolean isKeyDown(char c) {return keyStates.getOrDefault(c,false);}
}
public abstract class GameObject {
protected Graphics graphics = Renderer.getInstance().getGraphics();
protected final ObjectType type;
protected float x,y,r;
protected GameObject(ObjectType objectType, float x, float y, float r) {
this.type = objectType;
this.x = x;
this.y = y;
this.r = r;
Registry.getInstance().add(this);
}
public abstract void tick();
public abstract void render();
public void destroy() { Registry.getInstance().remove(this); }
public float getX() { return x; }
public void setX(float x) { this.x = x; }
public float getY() { return y; }
public void setY(float y) { this.y = y; }
public float getR() { return r; }
public void setR(float r) { this.r = r; }
}
public class Player extends GameObject {
private final Controller controller;
public Player(float x, float y, float r) {
super(ObjectType.PLAYER, x, y, r);
controller = Controller.getInstance();
}
#Override
public void tick() {
this.x += 1;
if (controller.isKeyDown('w')) x += 2;
if (controller.isKeyDown('a')) y -= 2;
if (controller.isKeyDown('s')) x -= 2;
if (controller.isKeyDown('d')) y += 2;
}
#Override
public void render() {
graphics.setColor(Color.BLUE);
graphics.fillRect((int) (this.x-12),(int) (this.y-12), 24,24);
}
}
The problem lies in your handling of Graphics. There's only ONE active Graphics object you can effectively address.
Refactor your code, so that you pass the current Graphics object via parameter through the target methods (like here: Player.render() should become Player.render(Gpahics g). And get rid of the Gameobject.graphics member variable. That is the culprit.
Adding to that, the best way to do simple rendering is to override the paint(Graphics g) method or the paintComponents(Graphics g), and from outside call repaint() on the JPanel/Canvas. This way the UI instigates drawing itself, takes care of the actual frequency, and draws default components/design too if there is some.
When i try to set value to BufferedImage called dinoImage in Dino.java in a constructor i just get a blank screen every time (second picture) because repaint() is not being called, but if i set it to null it is working just fine but without this image (first picture).
No exceptions, everything seems fine in this code, this problem appears when i try to set value to this field using static method getImage of Resource.java which uses this line of code ImageIO.read(new File(path)) and it causes that repaint() is not being called, i guess this line causes such weird behavior but i dont know how to solve it.
Main.java
public class Main {
public static void main(String[] args) {
GameWindow gameWindow = new GameWindow();
gameWindow.startGame();
}
}
GameWindow.java
public class GameWindow extends JFrame {
private GameScreen gameScreen;
public GameWindow() {
super("Runner");
setSize(1000, 500);
setVisible(true);
setResizable(false);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
gameScreen = new GameScreen();
add(gameScreen);
}
public void startGame() {
gameScreen.startThread();
}
}
GameScreen.java
public class GameScreen extends JPanel implements Runnable, KeyListener {
private Thread thread;
public static final double GRAVITY = 0.1;
public static final int GROUND_Y = 300;
private Dino dino;
public GameScreen() {
thread = new Thread(this);
dino = new Dino();
}
public void startThread() {
thread.start();
}
#Override
public void run() {
while(true) {
try {
Thread.sleep(20);
dino.updatePosition();
repaint();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
// g.clearRect(0, 0, getWidth(), getHeight());
g.setColor(Color.RED);
g.drawLine(0, GROUND_Y, getWidth(), GROUND_Y);
dino.draw(g);
}
#Override
public void keyTyped(KeyEvent e) {
}
#Override
public void keyPressed(KeyEvent e) {
System.out.println("Key Pressed");
dino.jump();
}
#Override
public void keyReleased(KeyEvent e) {
System.out.println("Key Released");
}
}
Dino.java
public class Dino {
private double x = 100;
private double y = 100;
private double speedY = 0;
private BufferedImage dinoImage;
public Dino() {
dinoImage = getImage("data/dino.png");
}
public void updatePosition() {
if(y + speedY >= GROUND_Y - 100) {
speedY = 0;
y = GROUND_Y - 100;
} else {
speedY += GRAVITY;
y += speedY;
}
}
public void jump() {
if(y == GROUND_Y - 100) {
speedY = -5;
y += speedY;
}
}
public void draw(Graphics g) {
g.setColor(Color.BLACK);
g.drawRect((int)x, (int)y, 100, 100);
g.drawImage(dinoImage, (int)x, (int)y, null);
}
}
Resource.java
public class Resource {
public static BufferedImage getImage(String path) {
BufferedImage image = null;
try {
image = ImageIO.read(new File(path));
} catch (IOException e) {
e.printStackTrace();
}
return image;
}
}
setSize(1000, 500);
setVisible(true);
setResizable(false);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
gameScreen = new GameScreen();
add(gameScreen);
Swing components need to be added to the frame BEFORE the frame is made visible. Otherwise the panel has a size of (0, 0) and there is nothing to paint.
The code should be something like:
gameScreen = new GameScreen();
add(gameScreen);
setSize(1000, 500);
setVisible(true);
I am making a game and I ran into a key ghosting problem (where the program only detects one keypress at a time, so the player can't go diagonally). I was watching this tutorial: https://www.youtube.com/watch?v=5UaEUrbpDPE
I followed everything they said and it still only detects one key at a time.
Main:
public class Main extends JApplet implements Runnable, KeyListener {
private static final long serialVersionUID = 1L;
public static int width = 900;
public static int height = 600;
public static int fps = 60;
public static Main instance;
public static Ailoid ailoid = new Ailoid();
public static Player player = new Player();
// Initialize
public void init() {
setSize(width, height);
setBackground(Color.white);
addKeyListener(this);
setFocusable(true);
setFocusTraversalKeysEnabled(false);
requestFocus();
instance = this;
ailoid.setLocation(new Location(100, 100));
AlienManager.registerAlien(ailoid);
player.setLocation(new Location(400, 400));
}
// Paint graphics
public void paint(Graphics g) {
super.paint(g);
paintComponent(g);
}
public void paintComponent(Graphics g) {
for (Alien alien : AlienManager.getAliens()) {
Location loc = alien.getLocation();
g.setColor(Color.GREEN);
g.fillRect(loc.getX(), loc.getY(), 10, 25);
}
g.setColor(Color.BLUE);
Location loc = Main.player.getLocation();
g.fillRect(loc.getX(), loc.getY(), 10, 25);
}
// Thread start
#Override
public void start() {
Thread thread = new Thread(this);
thread.start();
}
// Thread stop
#Override
public void destroy() {
}
// Thread run
#Override
public void run() {
Thread thread = new Thread(this);
while (thread != null) {
Updater.run();
repaint();
try {
// 1000 divided by fps to get frames per second
Thread.sleep(1000 / fps);
}
catch (InterruptedException e) {
e.printStackTrace();
}
}
}
#Override
public void keyPressed(KeyEvent evt) {
if (!KeysDown.get().contains(evt.getKeyCode()))
KeysDown.add(new Integer(evt.getKeyCode()));
KeyPress.run(evt);
}
#Override
public void keyReleased(KeyEvent evt) {
KeysDown.remove(new Integer(evt.getKeyCode()));
}
#Override
public void keyTyped(KeyEvent evt) {
}
}
KeysDown:
public class KeysDown {
private static ArrayList<Integer> keysDown = new ArrayList<Integer>();
public static ArrayList<Integer> get() {
return keysDown;
}
public static void add(Integer key) {
keysDown.add(key);
}
public static void remove(Integer key) {
keysDown.remove(key);
}
}
KeyPress:
public class KeyPress {
public static void run(KeyEvent evt) {
if (KeysDown.get().contains(KeyEvent.VK_RIGHT)) {
Main.player.moveRight();
}
else if (KeysDown.get().contains(KeyEvent.VK_LEFT)) {
Main.player.moveLeft();
}
else if (KeysDown.get().contains(KeyEvent.VK_DOWN)) {
Main.player.moveDown();
}
else if (KeysDown.get().contains(KeyEvent.VK_UP)) {
Main.player.moveUp();
}
}
}
Thank you!
Again as I have mentioned in previous comments:
Don't draw directly on the JApplet or in any top-level window.
If you give your applet a paintComponent method, it won't override any applet methods and won't gain the benefit of double buffering.
Instead draw in the paintComponent method of a JPanel, an thereby gain the benefit of double buffering.
Use Key Bindings not a KeyListener.
Also, I like to use a Swing Timer for simple game loops.
In the code below, I use an enum called Direction to encapsulate the idea of directions on the screen.
I then put the for Directions together with Boolean.FALSE in a Map<Direction, Boolean> called dirMap.
I run a Swing Timer continuously, polling the state of this Map and move a sprite based on the state of Booleans held by the dirMap.
I change the state of the map held values in my Key Binding Actions. So if the down key is pressed, its action will change the Direction.DOWN associated value in the Map to true, and when released, the Direction.DOWN associated value will be changed back to false.
For example:
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.EnumMap;
import javax.imageio.ImageIO;
import javax.swing.*;
#SuppressWarnings("serial")
public class AnimateExample extends JPanel {
public static final String DUKE_IMG_PATH = // https://duke.kenai.com/iconSized/duke.gif
"https://duke.kenai.com/iconSized/duke4.gif";
private static final int PREF_W = 800;
private static final int PREF_H = 800;
private static final int TIMER_DELAY = 20;
private static final String KEY_DOWN = "key down";
private static final String KEY_RELEASE = "key release";
public static final int TRANSLATE_SCALE = 3;
private static final String BACKGROUND_STRING = "Use Arrow Keys to Move Image";
private static final Font BG_STRING_FONT = new Font(Font.SANS_SERIF,
Font.BOLD, 32);
private EnumMap<Direction, Boolean> dirMap =
new EnumMap<AnimateExample.Direction, Boolean>(Direction.class);
private BufferedImage image = null;
private int imgX = 0;
private int imgY = 0;
private int bgStringX;
private int bgStringY;
public AnimateExample() {
for (Direction dir : Direction.values()) {
dirMap.put(dir, Boolean.FALSE);
}
try {
URL imgUrl = new URL(DUKE_IMG_PATH);
image = ImageIO.read(imgUrl);
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
new Timer(TIMER_DELAY, new TimerListener()).start();
// here we set up our key bindings
int condition = JComponent.WHEN_IN_FOCUSED_WINDOW;
InputMap inputMap = getInputMap(condition);
ActionMap actionMap = getActionMap();
for (final Direction dir : Direction.values()) {
// for the key down key stroke
KeyStroke keyStroke = KeyStroke.getKeyStroke(dir.getKeyCode(), 0,
false);
inputMap.put(keyStroke, dir.name() + KEY_DOWN);
actionMap.put(dir.name() + KEY_DOWN, new AbstractAction() {
#Override
public void actionPerformed(ActionEvent arg0) {
dirMap.put(dir, true);
}
});
// for the key release key stroke
keyStroke = KeyStroke.getKeyStroke(dir.getKeyCode(), 0, true);
inputMap.put(keyStroke, dir.name() + KEY_RELEASE);
actionMap.put(dir.name() + KEY_RELEASE, new AbstractAction() {
#Override
public void actionPerformed(ActionEvent arg0) {
dirMap.put(dir, false);
}
});
}
FontMetrics fontMetrics = getFontMetrics(BG_STRING_FONT);
int w = fontMetrics.stringWidth(BACKGROUND_STRING);
int h = fontMetrics.getHeight();
bgStringX = (PREF_W - w) / 2;
bgStringY = (PREF_H - h) / 2;
}
#Override
public Dimension getPreferredSize() {
return new Dimension(PREF_W, PREF_H);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
g.setFont(BG_STRING_FONT);
g.setColor(Color.LIGHT_GRAY);
g2.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING,
RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
g.drawString(BACKGROUND_STRING, bgStringX, bgStringY);
if (image != null) {
g.drawImage(image, imgX, imgY, this);
}
}
private class TimerListener implements ActionListener {
public void actionPerformed(java.awt.event.ActionEvent e) {
for (Direction dir : Direction.values()) {
if (dirMap.get(dir)) {
imgX += dir.getX() * TRANSLATE_SCALE;
imgY += dir.getY() * TRANSLATE_SCALE;
}
}
repaint();
};
}
enum Direction {
Up(KeyEvent.VK_UP, 0, -1), Down(KeyEvent.VK_DOWN, 0, 1), Left(
KeyEvent.VK_LEFT, -1, 0), Right(KeyEvent.VK_RIGHT, 1, 0);
private int keyCode;
private int x;
private int y;
private Direction(int keyCode, int x, int y) {
this.keyCode = keyCode;
this.x = x;
this.y = y;
}
public int getKeyCode() {
return keyCode;
}
public int getX() {
return x;
}
public int getY() {
return y;
}
}
private static void createAndShowGui() {
AnimateExample mainPanel = new AnimateExample();
JFrame frame = new JFrame("Animate Example");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
For more on Key Bindings, please check out the informative tutorial which you can find here.
I want to, when i click the "d" button, start a timer. This is to animate a player walking. The timer doesn't start when i press the key, how do i do that?
The code I have is this:
public class Game extends JPanel implements KeyListener {
//Player variables
private BufferedImage playerStanding;
private BufferedImage playerWalking;
private BufferedImage playerFrame;
private boolean walking = false;
private final int PLAYER_HEIGHT = 100;
private final int PLAYER_WIDTH = 100;
private final int INITIAL_X = 0;
private final int INITIAL_Y = 500;
private int x = INITIAL_X;
private int y = INITIAL_Y;
//The timer I want to start on keypress-> "d"
private Timer playerAnimationTimer;
public Game() {
setPreferredSize(new Dimension(800, 800));
setBackground(Color.CYAN);
//Player
try {
playerStanding = ImageIO.read(getClass().getResource("player1.gif"));
playerWalking = ImageIO.read(getClass().getResource("player2.gif"));
playerFrame = playerStanding;
}
catch (IOException ex) {
ex.printStackTrace();
}
playerAnimationTimer = new Timer(500, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
walking = !walking;
playerFrame = walking ? playerWalking : playerStanding;
x += 10;
if (x > getWidth() - PLAYER_WIDTH) {
x = INITIAL_X;
}
repaint();
}
});
playerAnimationTimer.setRepeats(true);
}
public Dimension setPreferredSize() {
return new Dimension(800, 800);
}
#Override
public void paintComponent(Graphics graphics) {
super.paintComponent(graphics);
Graphics2D graphics2D = (Graphics2D) graphics;
if (playerFrame != null) {
graphics2D.drawImage(playerFrame, x, y, PLAYER_WIDTH, PLAYER_HEIGHT, this);
}
graphics2D.dispose();
}
#Override
public void keyTyped(KeyEvent e) {
//This doesn't work
playerAnimationTimer.start();
}
#Override
public void keyPressed(KeyEvent e) {
}
#Override
public void keyReleased(KeyEvent e) {
}
}
//The class to hold the gamepanel
public class StartGame extends JFrame implements ActionListener {
private static JButton startGame = new JButton();
StartGame() {
setDefaultCloseOperation(WindowConstants.HIDE_ON_CLOSE);
setSize(200, 100);
setVisible(true);
setBackground(Color.BLUE);
setLocationRelativeTo(null);
startGame.setText("Play!");
startGame.setSize(100, 25);
startGame.addActionListener(this);
add(startGame);
}
#Override
public void actionPerformed(ActionEvent e) {
if (e.getSource() == startGame) {
this.setVisible(false);
new GameWindow();
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new StartGame();
}
});
}
}
How could I make the timer start when I click the "d" button?
Your KeyListener doesn't work because you never add the KeyListener to anything much less to a component that has focus, which is needed for a KeyListener to work.
I suggest that you instead use Key Bindings as a cleaner safer way to capture the desired key press.
As an aside, never dispose of a Graphics object that is given to you from the JVM.
For a better answer, please edit your code to make it comply with the mcve standard. You should use no images files, and it should compile and run for us unaltered.
You could set the private Timer like you did and start it like this...
public void startTimer(){
timer.start();
timer.setRepeats(true);
}
How can I obtain the coordinates of the cursor on a JPanel? I've tried using this:
MouseInfo.getPointerInfo().getLocation();
But this returns the location on the screen. I tried using the mouseMoved(MouseEvent m) method and then get the coordinates from m.getX() and m.getY(), but that method isn't being called. (I am using MouseListener).
Here's my Panel class:
public class Panel extends JPanel implements Runnable, KeyListener, MouseListener {
// serial
private static final long serialVersionUID = -2066956445832373537L;
// dimensions
public static final int WIDTH = 800;
public static final int HEIGHT = 600;
// game loop
private Thread thread;
private boolean running;
private final int FPS = 30;
private final int TARGET_TIME = 1000 / FPS;
// drawing
private BufferedImage image;
private Graphics2D g;
// status handler
private StatusHandler statusHandler;
// constructor
public Panel() {
setPreferredSize(new Dimension(WIDTH, HEIGHT));
setFocusable(true);
requestFocus();
}
public void addNotify() {
super.addNotify();
if(thread == null) {
addKeyListener(this);
addMouseListener(this);
thread = new Thread(this);
thread.start();
}
}
public void run() {
init();
long start;
long elapsed;
long wait;
// game loop
while(running) {
start = System.nanoTime();
update();
render();
renderToScreen();
elapsed = System.nanoTime() - start;
wait = TARGET_TIME - elapsed / 1000000;
if(wait < 0) wait = TARGET_TIME;
try {
Thread.sleep(wait);
}
catch(Exception e) {
e.printStackTrace();
}
}
}
private void init() {
running = true;
image = new BufferedImage(WIDTH, HEIGHT, 1);
g = (Graphics2D) image.getGraphics();
statusHandler = new StatusHandler();
}
private void update() {
statusHandler.update();
}
private void render() {
statusHandler.render(g);
}
private void renderToScreen() {
Graphics g2 = getGraphics();
g2.drawImage(image, 0, 0, WIDTH, HEIGHT, null);
}
public void keyTyped(KeyEvent key) {}
public void keyPressed(KeyEvent key) {
KeyInput.setKey(key.getKeyCode(), true);
}
public void keyReleased(KeyEvent key) {
KeyInput.setKey(key.getKeyCode(), false);
}
public void mouseClicked(MouseEvent m) {}
public void mouseReleased(MouseEvent m) {
MouseInput.setButton(m.getButton(), false);
MouseInput.setMouseEvent(m);
}
public void mouseEntered(MouseEvent m) {}
public void mouseExited(MouseEvent m) {}
public void mousePressed(MouseEvent m) {
MouseInput.setButton(m.getButton(), true);
MouseInput.setMouseEvent(m);
}
}
The mouseMoved event is handled by a MouseMotionListener.