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Thread: help me!

  1. #1
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    Angry help me!

    Arrrgh! This is hopeless! My dream is to be a game developer, and I have tried to make a simple 2D game. Every single time, I tell you, every single time, I get stuck with something. Before my imageIO hasn't been working, so I decided to make a game with only javas Graphics2D. Just when I got started I encounter a problem, my game loop doesn't work. I use a simple Thread game loop. I put print messages in my code to debug that way. The loop runs once and then stop! Why?

    Here is my code:

    package shooter;
     
    import java.awt.Color;
    import java.awt.Graphics;
    import java.awt.Graphics2D;
    import java.awt.event.KeyAdapter;
    import java.awt.event.KeyEvent;
     
    import javax.swing.JPanel;
     
    public class GamePanel extends JPanel implements Runnable {
     
    	private boolean paused = false;
    	private boolean gameover = false;
    	private int playerX, playerY, playerW, playerH, playerDx;
    	private Thread thread;
     
    	public GamePanel() {
    		thread = new Thread(this);
     
    		playerX = Game.WIDTH / 2 - 15;
    		playerY = 360;
    		playerW = 30;
    		playerH = 20;
     
    		addKeyListener(new KeyL());
     
    		thread.start();
    	}
     
    	public void paint(Graphics gf) {
     
    		Graphics2D g = (Graphics2D)gf;
     
    		//paints the background.
    		g.setColor(Color.BLACK);
    		g.fillRect(0, 0, Game.WIDTH, Game.HEIGHT);
     
    		//paints the player
    		g.setColor(Color.WHITE);
    		g.fillRect(playerX, playerY, playerW, playerH);
     
    		System.out.println("painted!");
    	}
     
    	//game loop
    	@Override
    	public void run() {
    		move();
    		repaint();
     
    		System.out.println("looped!");
    		try {
    			Thread.sleep(17);
    		}catch(Exception ex){
    			System.out.println(ex);
    		}
    	}
     
    	//checks all collisions in game
    	public void checkCollisions() {
     
    		//checks if the player its the walls.
    		if (playerX + playerDx < 0) {
    			playerX = 0;
    			playerDx = 0;
    		}
    		else if (playerX + playerDx > Game.WIDTH) {
    			playerX = Game.WIDTH - playerW;
    			playerDx = 0;
    		}
    	}
     
    	//moves all entities.
    	public void move() {
    		playerX += playerDx;
    		System.out.println("Moved!");
    	}
     
    	private class KeyL extends KeyAdapter {
     
    		public void keyPressed(KeyEvent e) {
    			int key = e.getKeyCode();
     
    			if (key == KeyEvent.VK_A) {
    				playerDx = -2;
    				System.out.println("moving left");
    			}
    			if (key == KeyEvent.VK_D) {
    				playerDx = 2;
    				System.out.println("moving right");
    			}
    		}
    	}
    }

    Yes, I know there is no main class. That one is in the JFrame class but I know the error isn't there.

    This is very frustrating! Earlier I have just given up, but know I decided to get help instead.

    Please, please, PLEASE, help me!

    P.S. The controls doesn't work either.
    Last edited by Dr.Code; June 26th, 2012 at 12:27 PM.

  2. #2
    Crazy Cat Lady KevinWorkman's Avatar
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    Default Re: help me!

    A Thread's run() method is only called once, not repeatedly. If you want it to run more than once, you have to set up a loop inside of it.

    I would recommend that you use a Swing Timer instead though.
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    Dr.Code (June 26th, 2012)

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    Default Re: help me!

    Quote Originally Posted by KevinWorkman View Post
    A Thread's run() method is only called once, not repeatedly. If you want it to run more than once, you have to set up a loop inside of it.

    I would recommend that you use a Swing Timer instead though.
    Thank you! It worked! Sort of... The controls don't work? I don't know why. Anyone that can help me?

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    Default Re: help me!

    You need to set the focus to the JPanel,
    Make it focusable first and then request the focus.

    You may also want to make it so the player stops moving when the keys are released. Unless your intent was to have them always moving.
    Last edited by JJeng; June 26th, 2012 at 02:45 PM.

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    Dr.Code (June 27th, 2012)

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    Default Re: help me!

    Quote Originally Posted by JJeng View Post
    You need to set the focus to the JPanel,
    Make it focusable first and then request the focus.
    Thank you!

    Quote Originally Posted by JJeng View Post
    You may also want to make it so the player stops moving when the keys are released. Unless your intent was to have them always moving.
    Yeah, I forgot that .

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