Repaint Problems

I was wondering how i could get the image to move by a set amount of pixels(which now is supposed to be 5) instead of making one big leap to the if statement in the loop which is what is happening now.

import java.applet.Applet;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;


public class main extends Applet implements KeyListener{
public int x = 0;
public int y = 0;

public void init(){
setBackground(Color.CYAN);
addKeyListener(this);
}

public void paint( Graphics g){
g.setColor(Color.BLUE);
g.fillRect(x, y, 10, 10);
g.setColor(Color.BLACK);
g.drawRect(x, y, 10, 10);
g.drawRect(x+1, y+1, 8, 8); 
}

public void keyTyped(KeyEvent input){
char key = input.getKeyChar();
while (key == 'd'){
repaint();
if (x < 600){
x = (x + 5);
try {
Thread.sleep(25);
} catch (InterruptedException e){}
}else{
break;
}
}
}
public void keyPressed(KeyEvent input){
}
public void keyReleased(KeyEvent input){
}
}

For convenience, here is the code so you both don't have to jump between threads.

import javax.swing.*;
import java.awt.*;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.util.*;

public class Snake extends JFrame implements Runnable, ActionListener {

	// number of squares in the grid, size of each of them
	private static final int SIZE = 25, WIDTH = 20;
	// the labels for displaying the snake and its foods
	private SnakeLabel[][] label = new SnakeLabel[SIZE][SIZE];
	// arrayList containing all of the snake position (Labels)
	private SnakeList snakeList = new SnakeList();
	// the label displaying if I am running or not and the size of the snake
	private JLabel statusLabel = new JLabel();
	// random number generator to find a new spot for a new food when I eat one
	private Random random = new Random();
	// if I am in a pause state or not
	boolean pause = false;
	// the button to switch from pause to not pause
	private JButton pauseResume = new JButton("Pause");
	// which direction I am running and where is my head
	private int directionX = 0, directionY = -1, headX, headY;
   
	Snake() {
		super("Snake Game");
		// to hold all the labels
		JPanel panel = new JPanel(new GridLayout(SIZE, SIZE, 1, 1));
		panel.setBackground(Color.BLUE);
		panel.setBorder(BorderFactory.createLineBorder(Color.BLUE));
		// create all the JLabel
		for(int j = 0; j < SIZE; j++) {
			for(int i = 0; i < SIZE; i++) {
				label[i][j] = new SnakeLabel(i, j);
				panel.add(label[i][j]);
			}
		}
	   
		// add the 4 foods
		initFood();
		// the snake in the middle of everything initial size 8
		headX = SIZE / 2;
		headY = (SIZE / 2) - 4;
		// declare these label as holding the snake
		// registering them in the arrayList
		for(int i = 0; i < 8; i++)
			snakeList.addLabel(label[headX][headY + i]);
	   
		add(panel, BorderLayout.CENTER);
		// label if I am running well and size of the snake
		statusLabel.setHorizontalAlignment(SwingConstants.CENTER);
		add(statusLabel, BorderLayout.NORTH);
		// listener so the pause button will work
		pauseResume.addActionListener(this);
		add(pauseResume, BorderLayout.SOUTH);
		// general JFrame stuff its size and visible
		setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
		setSize(SIZE * WIDTH, SIZE * WIDTH);
		setVisible(true);
		Thread thread = new Thread(this);
		thread.start();
	}
   
	// to put the initial 4 food labels in 1/4 of the grid
	private void initFood() {
		// north/west at 1/4 of the grid
		int x = SIZE / 4;
		int y = x;
		label[x][y].setFood(true);
		// north east so x is the same delta from the end
		x = SIZE - x;
		label[x][y].setFood(true);
		// south/west
		y = x;
		x = SIZE / 4;
		label[x][y].setFood(true);
		// south east
		x = y;
		label[x][y].setFood(true);		
	}
	// run as a thread to move the snake
	public void run() {
		for(;;) {
			// wait according to snake length... determine an empiric way
			try {
				Thread.sleep(10000L / snakeList.size());
			}
			catch(Exception e) {}
			// if the "Pause" button was pushed go to next turn
			if(pause)
				continue;
			// update snake head position
			headX += directionX;
			headY += directionY;
			// check if we are going out of bound
			if(headX < 0 || headX >= SIZE || headY < 0 || headY >= SIZE) {
				statusLabel.setText("Out of bound... length: " + snakeList.size());
				return;
			}
			// check if we are eating ourself
			if(label[headX][headY].isSnake) {
				statusLabel.setText("You eat yourself... length: " + snakeList.size());
				return;
			}
			// if we hit food
			if(label[headX][headY].isFood) {
				snakeList.updateHead();	 // without updating tail
				// found new place for food
				for(;;) {
					int x = random.nextInt(SIZE);
					int y = random.nextInt(SIZE);
					// start again if new random place is already in the snake or is already food
					if(label[x][y].isFood)
						continue;
					if(label[x][y].isSnake)
						continue;
					// ok good dpot not used yet/// declare it as food
					label[x][y].setFood(true);
					break;
				}
			}
			else {
				snakeList.updateTail();	 // first if I pass on my back
				snakeList.updateHead();
			}
			statusLabel.setText("Running... snake length: " + snakeList.size());
		}
	}
	// called when the pause/resume button is hit
	public void actionPerformed(ActionEvent e) {
		// change the state
		pause = !pause;
		// updtae button text accordingly
		if(pause)
			pauseResume.setText("Resume");
		else
			pauseResume.setText("Pause");
	}
	// to run the whole damned thing
	public static void main(String[] args) {

		SwingUtilities.invokeLater(new Runnable() {
			public void run() {
				new Snake();
			}
		});
	}
	// arrtay list that contains the position taken by the snake
	class SnakeList extends ArrayList<SnakeLabel> {
	   
		// for initial build when we install the snake first positions
		boolean addLabel(SnakeLabel sl) {
			sl.setSnake(true);
			return super.add(sl);
		}
		// remove (make free) the tail of the snake
		void updateTail() {
			SnakeLabel sl = remove(size() - 1);
			sl.setSnake(false);
		}
		// to update the head to new position
		void updateHead() {
			label[headX][headY].setSnake(true);
			add(0, label[headX][headY]);
		}
	}
	// extends JLabel to keep coordinate X and Y and have a mouseListener if cliked
	class SnakeLabel extends JLabel implements MouseListener{
		private int x, y;
		// init not food not snake
		boolean isFood = false;
		boolean isSnake = false;
		// constructor
		SnakeLabel(int x, int y) {
			super("");
			// save my coordinates
			this.x = x; this.y = y;
			// opaque because I use background to represent myself
			setOpaque(true);
			// so I will react if I am cleicked
			addMouseListener(this);
			// default color
			setBackground(Color.WHITE);
		}
		// declares me as a food case or not
		void setFood(boolean state) {
			isFood = state;
			// change color accordingly
			if(state)
				setBackground(Color.RED);
			else
				setBackground(Color.WHITE);
		}
		// declares me as part of the snake or not
		void setSnake(boolean state) {
			isSnake = state;
			// change my color accordingly
			if(state) {
				setBackground(Color.BLUE);
				isFood = false;	  // slot availabel again if I just eat it for later use
			}
			else {
				setBackground(Color.WHITE);
			}
		}
		// ok click on me
		public void mouseClicked(MouseEvent e) {
			// so am I going vertically or horitonaly
			if(directionX == 0) {
				// if clicked to my left
				if(x < headX) {
					// update the way I am going
					directionX = -1;
					directionY = 0;
				}	
				else if(x > headX) {   // is it to my rioght ?
					directionX = +1;
					directionY = 0;					
				}
			}
			else {				  // OK I am moving horizontaly
				if(y < headY) {	 // to my left
					directionY = -1;
					directionX = 0;
				}
				if(y > headY) {	 // to my right ?
					directionY = +1;
					directionX = 0;
				}
			   
			}
		}
		// do not react to those
		public void mouseEntered(MouseEvent arg0) {
		}
		public void mouseExited(MouseEvent arg0) {
		}
		public void mousePressed(MouseEvent arg0) {
		}
		public void mouseReleased(MouseEvent arg0) {
		}
	   
	}
}

And the nicer version:

import javax.swing.*;
import java.awt.*;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.util.*;

public class Snake extends JFrame implements Runnable, ActionListener {

	private static final long serialVersionUID = 123654L;   // just to avoid compile warning
	// number of squares in the grid, size of each of them
	private static final int SIZE = 25, WIDTH = 20;
	// the labels for displaying the snake and its foods
	private SnakeLabel[][] label = new SnakeLabel[SIZE][SIZE];
	// arrayList containing all of the snake position (Labels)
	private SnakeList snakeList = new SnakeList();
	// the label displaying if I am running or not and the size of the snake
	private JLabel statusLabel = new JLabel("Initializing");
	// random number generator to find a new spot for a new food when I eat one
	private Random random = new Random();
	// if I am in a pause state or not
	boolean pause = false;
	// the button to switch from pause to not pause
	private JButton pauseResume = new JButton("Pause");
	// which direction I am running and where is my head
	private int directionX = 0, directionY = -1, headX, headY;
	// the refresh rate
	private long refreshRate;

	Snake() {
		super("Snake Game");
		// to hold all the labels with a gap of 1 pixel
		JPanel panel = new JPanel(new GridLayout(SIZE, SIZE, 1, 1));
		// the same color as the Snake so the back will show a continuos snake
		panel.setBackground(Color.BLUE);
		panel.setBorder(BorderFactory.createLineBorder(Color.BLUE));
		// create all the JLabels
		initLabels(panel);
	   
		// add the 4 foods
		initFood();
		// init the snake the length of a quarter of our size
		initSnake(SIZE / 4);
		add(panel, BorderLayout.CENTER);
	   
		// label if I am running well and size of the snake
		statusLabel.setHorizontalAlignment(SwingConstants.CENTER);
		statusLabel.setOpaque(true);
		statusLabel.setBackground(Color.YELLOW);
		add(statusLabel, BorderLayout.NORTH);
		// listener so the pause button will work
		pauseResume.setForeground(Color.RED);
		pauseResume.addActionListener(this);
		add(pauseResume, BorderLayout.SOUTH);
		// general JFrame stuff its size and visible
		setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
		setSize(SIZE * WIDTH - 5, SIZE * WIDTH - 5);
		setVisible(true);
		// start the thread that move the snakes
		Thread thread = new Thread(this);
		thread.start();
	}
   
	// to initialize the labels filling the grid
	// this method is called only once
	private void initLabels(JPanel p) {
		for(int j = 0; j < SIZE; j++) {
			for(int i = 0; i < SIZE; i++) {
				label[i][j] = new SnakeLabel(i, j);
				p.add(label[i][j]);
			}
		}
	   
	}
	// to put the initial 4 food labels in 1/4 of the grid
	// this method will be called only once
	private void initFood() {
		// north/west at 1/4 of the grid
		int x = SIZE / 4;
		int y = x;
		label[x][y].setFood(true);
		// north east so x is the same delta from the end
		x = SIZE - x;
		label[x][y].setFood(true);
		// south/west
		y = x;
		x = SIZE / 4;
		label[x][y].setFood(true);
		// south east
		x = y;
		label[x][y].setFood(true);		
	}
   
	// to position the snake at the beginning of game
	private void initSnake(int length) {
		// the snake in the middle of everything initial size of length
		headX = SIZE / 2;
		headY = (SIZE / 2) - (length / 2);
		// declare these label as holding the snake
		// registering them in the arrayList
		for(int i = headY; i < headY + length; i++)
			snakeList.addLabel(label[headX][i]);
		// set the color for the first time
		snakeList.updateColor();
	}
	   
	// run as a thread to move the snake
	public void run() {
		for(;;) {
			// wait according to snake length... determine an empiric way
			refreshRate = 5000L / (snakeList.size() / 2);
			// manage to have at least a minimum refresh rate
			if(refreshRate < 10L)
				refreshRate = 10L;
		   
			try {
				Thread.sleep(refreshRate);
			}
			catch(Exception e) {}
			// if the "Pause" button was pushed go to next turn
			if(pause)
				continue;
			// update snake head position
			headX += directionX;
			headY += directionY;
			// check if we are going out of bound
			if(headX < 0 || headX >= SIZE || headY < 0 || headY >= SIZE) {
				statusLabel.setText("Out of bound... length: " + snakeList.size());
				return;
			}
			// check if we are eating ourself
			if(label[headX][headY].isSnake) {
				statusLabel.setText("You eat yourself... length: " + snakeList.size());
				return;
			}
			// if we hit food
			if(label[headX][headY].isFood) {
				snakeList.updateHead();	 // without updating tail
				// found new place for food
				for(;;) {
					int x = random.nextInt(SIZE);
					int y = random.nextInt(SIZE);
					// start again if new random place is already in the snake or is already food
					if(label[x][y].isFood)
						continue;
					if(label[x][y].isSnake)
						continue;
					// ok good dpot not used yet/// declare it as food
					label[x][y].setFood(true);
					break;
				}
			}
			else {
				snakeList.updateTail();	 // first if I pass on my back
				snakeList.updateHead();
			}
			statusLabel.setText("Running... snake length: " + snakeList.size()
											+ "	Refresh Rate: " + refreshRate + "/1000 sec");
		}
	}
	// called when the pause/resume button is hit
	public void actionPerformed(ActionEvent e) {
		// change the state
		pause = !pause;
		// updtae button text accordingly
		if(pause)
			pauseResume.setText("Resume");
		else
			pauseResume.setText("Pause");
	}
	// to run the whole damned thing
	public static void main(String[] args) {

		SwingUtilities.invokeLater(new Runnable() {
			public void run() {
				new Snake();
			}
		});
	}
	// array list that contains the position taken by the snake
	private class SnakeList extends ArrayList<SnakeLabel> {
		private static final long serialVersionUID = 654321L;  // to avoid compile warning
		// the 2 colours of the snake
		private Color[] snakeColor = {new Color(0, 0, 255), new Color(75, 75, 255)};
		// for initial build when we install the snake first positions
		private boolean addLabel(SnakeLabel sl) {
			// flag the SnakeLabel as being part of the Snake
			sl.setSnake(true);
			// call father's method to add an object into the arrayList
			return add(sl);
		}
		// remove (make free) the tail of the snake
		private void updateTail() {
			SnakeLabel sl = remove(size() - 1);
			sl.setSnake(false);
		}
		// to update the head to new position
		private void updateHead() {
			// declare it as part of the snake
			label[headX][headY].setSnake(true);
			// add it to the head of the snake
			add(0, label[headX][headY]);
			// switch colors
			updateColor();
		}
	   
		// to put 2 colours in the snake
		private void updateColor() {
			int len = size();
			// the head in black
			get(0).setBackground(Color.BLACK);
			// variation of blue for the others
			for(int i = 1; i < len; i++) {
				get(i).setBackground(snakeColor[i % snakeColor.length]);
			}
		}
	} // end of inner class SnakeList
   
	// specialized JLabel to keep coordinate X and Y and have a mouseListener if cliked
	private class SnakeLabel extends JLabel implements MouseListener{
		private static final long serialVersionUID = 123456L;   // to avoid compile warning
		// my coordinates on the Grid so the mouseListener can know where I am situate
		private int x, y;
		// init not food and not snake
		boolean isFood = false;		 // not a food case
		boolean isSnake = false;		// not part of the snake
		// constructor
		SnakeLabel(int x, int y) {
			super("");
			// save my coordinates
			this.x = x; this.y = y;
			// opaque because I use background to represent myself
			setOpaque(true);
			// so I will react if I am cleicked
			addMouseListener(this);
			// default color
			setBackground(Color.WHITE);
		}
		// declares me as a food case or not
		private void setFood(boolean state) {
			isFood = state;
			// change color accordingly
			if(state)
				setBackground(Color.RED);	   // food color
			else
				setBackground(Color.WHITE);	 // regular color
		}
		// declares me as part of the snake or not
		private void setSnake(boolean state) {
			isSnake = state;
			// change my color accordingly
			if(state) {
				setFood(false);	  // make it available again as food slot
				setBackground(Color.BLUE);
			}
			else {
				setBackground(Color.WHITE);
			}
		}
	   
		// ok click on me I just chek for the Pressed event to react faster
		// (important when the snake goes very fast)
		public void mousePressed(MouseEvent e) {
			// so am I going vertically or horitonaly
			if(directionX == 0) {
				// if clicked on my same X nothing to do
				if(x == headX)
					return;
				directionY = 0;				// stop updating Y
				// if clicked to my left
				if(x < headX) {
					// update the way I am going
					directionX = -1;
				}	
				else  {   // so to my rioght
					directionX = +1;				
				}
			}
			else {				  // OK I am moving horizontaly
				if(y == headY)
					return;
				directionX = 0;
				if(y < headY) {	 // to my left
					directionY = -1;
				}
				else {	 // to my right
					directionY = +1;
				}				
			}
		}
		// do not react to those but as I implement MouseListener have have to implement these
		public void mouseEntered(MouseEvent arg0) {}
		public void mouseExited(MouseEvent arg0) {}
		public void mouseClicked(MouseEvent arg0) {}
		public void mouseReleased(MouseEvent arg0) {}
	   
	}  // end inner class SnakeLabel
}

@pbl - you should make this a tutorial. and definitely add a difficulty bar, because it's too easy now lol (i play a lot of video games) or make it so the snake speeds up every time he eats an apple.

This post has been edited by 333OnlyHalfEvil: 18 June 2009 - 02:04 AM

I'm trying to make "Snake" using a java applet but whene

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