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);
}
Related
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've written some code that essentially animates a sequence of images and adds them to a frame when I run the file.
I want to implement a functionality where I can add this animation to two different areas of a JPanel that has a BorderLayout (North and West).
I want to do this using a button but I don't know how to do that. I am new to event handling and layout managers.
How do I go about this?
My code for the animation:
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class ImageSequence extends JPanel implements ActionListener {
private ImageSQPanel imageSQPanel;
private static int frameNumber = -1;
private Timer timer;
private void buildUI(Container container, Image[] arrows) {
int fps = 10;
int delay = 1000 / fps;
timer = new Timer(delay, this);
timer.setInitialDelay(0);
timer.setCoalesce(true);
imageSQPanel = new ImageSQPanel(arrows);
container.add(imageSQPanel, BorderLayout.CENTER);
}
private synchronized void startAnimation() {
if (!timer.isRunning()) {
timer.start();
}
}
public void actionPerformed(ActionEvent e) {
frameNumber++;
imageSQPanel.repaint();
}
class ImageSQPanel extends JPanel {
Image arrowAnimation[];
ImageSQPanel(Image[] arrowAnimation) {
this.arrowAnimation = arrowAnimation;
}
//Draw the current frame of animation.
public void paintComponent(Graphics g) {
super.paintComponent(g); //paint background
//Paint the frame into the image.
try {
g.drawImage(arrowAnimation[ImageSequence.frameNumber % 10], 0, 0, this);
} catch (ArrayIndexOutOfBoundsException e) {
//On rare occasions, this method can be called
//when frameNumber is still -1. Do nothing.
}
}
}
//Invoked only when this is run as an application.
public static void main(String[] args) {
Image[] waving = new Image[7];
for (int i = 1; i <= 7; i++) {
waving[i - 1] = Toolkit.getDefaultToolkit().getImage(
"/Users/sarthaksachdeva/Documents/IntelliJ Projects/Animation/src/images/Arrow" + i + ".png");
}
JFrame f = new JFrame("ImageSequenceTimer");
f.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
ImageSequence controller = new ImageSequence();
controller.buildUI(f.getContentPane(), waving);
controller.startAnimation();
f.setSize(new Dimension(200, 200));
f.setVisible(true);
}
}
Im trying to create a game in java.
At the first I've made a Jpanel and made a FPS counter and the background was white.
after that I've tried to made that when you pressing ESCAPE, the Jpanel shutting down and then I've tried to make that when you pressing Space, the Background moving to green but after that, when Im trying to start, the Jpanel moving to grey background and the FPS counter has been disappear.
this is the frame class
public class Frame extends JFrame{
public static void main(String[] args) {
new Frame();
}
public Frame(){
new JFrame();
this.setTitle("Tower Defence - By Sahar Haine");
this.setDefaultCloseOperation(EXIT_ON_CLOSE);
this.setExtendedState(MAXIMIZED_BOTH);
this.setUndecorated(true);
this.setResizable(false);
this.setVisible(true);
Screen screen = new Screen(this);
this.add(screen);
}
this is the screen class:
public class Screen extends JPanel implements Runnable{
Thread thread = new Thread(this);
Frame frame;
private int fps = 0;
public int scene;
public Boolean running = false;
public Screen(Frame frame){
this.frame = frame;
this.frame.addKeyListener(new KeyHandller(this));
thread.start();
}
#Override
public void paintComponent(Graphics g){
g.clearRect(0, 0, this.frame.getWidth(), this.frame.getHeight());
g.drawString(fps + "", 10, 10);
if(scene == 0){
g.setColor(Color.BLUE);
}else{
}
g.setColor(Color.GREEN);
g.fillRect(0, 0, this.frame.getWidth(), this.frame.getHeight());
}
public void run() {
System.out.println("Success");
long lastFrame = System.currentTimeMillis();
int frames = 0;
running = true;
scene = 0;
while(running){
try {
repaint();
frames++;
if(System.currentTimeMillis() - 1000>= lastFrame){
fps = frames;
frames = 0;
lastFrame = System.currentTimeMillis();
}
Thread.sleep(1);
} catch (InterruptedException ex) {
Logger.getLogger(Screen.class.getName()).log(Level.SEVERE, null, ex);
}
}
System.exit(0);
}
public class KeyTyped{
public void keyESC(){
running = false;
}
public void keySPACE() {
scene = 1;
}
and this is the key handler class:
public class KeyHandler implements KeyListener{
private Screen screen;
private Screen.KeyTyped keyTyped;
public KeyHandler(Screen screen){
this.screen = screen;
this.keyTyped = this.screen.new KeyTyped();
}
public void keyTyped(KeyEvent e) {
}
public void keyPressed(KeyEvent e) {
int keyCode = e.getKeyCode();
System.out.println(e.getKeyCode());
if(keyCode == 27){
this.keyTyped.keyESC();
}
if(keyCode == 27){
this.keyTyped.keySPACE();
}
}
public void keyReleased(KeyEvent e) {
}
One issue that jumps out immediately is that you have hard coded "keyCode = 27" for both Escape and Space which is not correct. "27 - Escape" and "32 - Space". Rather than hard code the values, please use KeyEvent.VK_ESCAPE and KeyEvent.VK_SPACE as documented here, KeyEvents
EDIT 1
Also make certain that you draw the string AFTER the "Fill" or else the "Fill" will over paint the FPS string and you will not see it.
I think you have to call
super.paintComponent(g)
as the first line in your paintComponent method override.
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);
}
I am making a little game applet, and I have gotten to where the player should move around with the controls.
Main:
public class Main extends JApplet implements Runnable, KeyListener {
private static final long serialVersionUID = 1L;
private static DoubleBufferedCanvas canvas = new DoubleBufferedCanvas();
public static int width = 900;
public static int height = 600;
public static int fps = 60;
public static Ailoid ailoid = new Ailoid();
public static Player player = new Player();
// Initialize
public void init() {
setSize(width, height);
setBackground(Color.white);
add(canvas);
addKeyListener(this);
setFocusable(true);
setFocusTraversalKeysEnabled(false);
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);
}
// 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();
canvas.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) {
KeyPress.run(evt);
System.out.println("DEBUG");
}
#Override
public void keyReleased(KeyEvent evt) {
}
#Override
public void keyTyped(KeyEvent evt) {
}
}
What happens is that it only starts saying "debug" after I press tab. How would I make it work even if the player doesn't press tab before?
Your Applet most likely does not have the input focus.Try adding
this.requestFocus ()
to your init method.
Also note that a JApplet is a part of the Swing framework and thus not threadsafe as mentioned in the documentation
public static void main(String[] args) {
JFrame frame = new JFrame(GAME_TITLE);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setResizable(false);
sGame = new Game(GAME_WIDTH, GAME_HEIGHT);
frame.add(sGame);
frame.pack();
frame.setVisible(true);
frame.setIconImage(Resources.iconimage);
}
I had the same problem, it was caused in main by not calling everything in the correct order.
Originally I had setVisible(true) before I had passed sGame to .add and called frame.pack().
This code is what worked for me.