Continuous Movement in Snake

[djplatinumalex]

I am trying to find a way to allow the snake to continue to move after a key is pressed. I have tried using 4 boolean variables for each key but it only responds to one key and none after that. That has been a continuous issue. Does anyone know how to allow the movement to continue but change if an alternate key is pressed?

code:

import java.awt.*; import javax.swing.*; public class Snake extends Frame {     Image offScreenImage;     Graphics offScreenGraphics;     int numOfPieces = 1;     int[] [] snake = new int [200] [2];     int xChange = 0;     int yChange = 0;     int score = 0;     int prizeX = (int) ((Math.random () * 18) + 1) * 20;     int prizeY = (int) ((Math.random () * 16) + 3) * 20;     Menu game = new Menu ("Game");     Menu about = new Menu ("About");     MenuItem newGame = new MenuItem ("New Game");     MenuItem exit = new MenuItem ("Exit");     MenuItem aboutIt = new MenuItem ("About");     MenuBar menu = new MenuBar ();     public Snake ()     {         super ("Snake");         setSize (400, 400);         setResizable (false);         snake [0] [0] = 20;         snake [0] [1] = 60;         game.add (newGame);         game.add (exit);         about.add (aboutIt);         menu.add (game);         menu.add (about);         setMenuBar (menu);         show ();     }     public static void drawGrid (Graphics g)     {         int x = 20;         int y = 60;         for (int count = 0 ; count < 380 ; count += 20)         {             g.drawLine (x + count, y, x + count, 380);         }         for (int count = 0 ; count < 380 ; count += 20)         {             g.drawLine (x, y + count, 380, y + count);         }     }     public static void delay (int time)     {         try         {             Thread.sleep (time);         }         catch (Exception e)         {         }     }     public boolean keyDown (Event evt, int key)     {         char keyChar = (char) key;         if (key == Event.LEFT)         {             xChange = -20;             yChange = 0;             repaint ();         }         if (key == Event.RIGHT)         {             xChange = 20;             yChange = 0;             repaint ();         }         if (key == Event.UP)         {             xChange = 0;             yChange = -20;             repaint ();         }         if (key == Event.DOWN)         {             xChange = 0;             yChange = 20;             repaint ();         }         return true;     }     public boolean action (Event evt, Object obj)     {         if (evt.target == exit)             System.exit (0);         if (evt.target == aboutIt)             JOptionPane.showMessageDialog (null, "About: Snake\nBy: Alex Mikhailov\nDescription: Move around and collect the pieces\nDon't hit the wall or yourself!");         if (evt.target == newGame)         {             numOfPieces = 1;             snake [0] [0] = 20;             snake [0] [1] = 60;             xChange = 0;             yChange = 0;             score = 0;             prizeX = (int) ((Math.random () * 18) + 1) * 20;             prizeY = (int) ((Math.random () * 16) + 3) * 20;             repaint ();         }         return true;     }     public void paint (Graphics g)     {         int oldX = 0;         int oldY = 0;         int holdX = 0;         int holdY = 0;         String scoreString = "Score = " + score;         if (offScreenGraphics == null)         {             offScreenImage = createImage (size ().width, size ().height);             offScreenGraphics = offScreenImage.getGraphics ();         }         for (int count = 1 ; count < numOfPieces ; count++)         {             if (snake [0] [0] == snake [count] [0] && snake [0] [1] == snake [count] [1])             {                 JOptionPane.showMessageDialog (null, "You Have Died!");                 numOfPieces = 1;                 score = 0;                 repaint ();             }         }         if (numOfPieces == 1)         {             if (xChange != 0 || yChange != 0)             {                 snake [0] [0] += xChange;                 snake [0] [1] += yChange;                 offScreenGraphics.setColor (Color.black);                 drawGrid (offScreenGraphics);                 offScreenGraphics.setColor (Color.blue);                 offScreenGraphics.fillRect (prizeX, prizeY, 20, 20);                 offScreenGraphics.setColor (Color.green);                 offScreenGraphics.fillRect (snake [0] [0], snake [0] [1], 20, 20);                 g.drawImage (offScreenImage, 0, 0, this);                 delay (25);                 offScreenGraphics.setColor (Color.white);                 offScreenGraphics.fillRect (0, 0, 400, 400);                 offScreenGraphics.setColor (Color.black);                 offScreenGraphics.drawString (scoreString, 20, 55);             }         }         if (numOfPieces > 1)         {             if (xChange != 0 || yChange != 0)             {                 oldX = snake [0] [0];                 oldY = snake [0] [1];                 snake [0] [0] += xChange;                 snake [0] [1] += yChange;                 offScreenGraphics.setColor (Color.black);                 drawGrid (offScreenGraphics);                 offScreenGraphics.setColor (Color.blue);                 offScreenGraphics.fillRect (prizeX, prizeY, 20, 20);                 offScreenGraphics.setColor (Color.green);                 offScreenGraphics.fillRect (snake [0] [0], snake [0] [1], 20, 20);                 for (int count = 1 ; count < numOfPieces ; count++)                 {                     holdX = snake [count] [0];                     holdY = snake [count] [1];                     snake [count] [0] = oldX;                     snake [count] [1] = oldY;                     oldX = holdX;                     oldY = holdY;                     offScreenGraphics.setColor (Color.green);                     offScreenGraphics.fillRect (snake [count] [0], snake [count] [1], 20, 20);                 }                 g.drawImage (offScreenImage, 0, 0, this);                 delay (25);                 offScreenGraphics.setColor (Color.white);                 offScreenGraphics.fillRect (0, 0, 400, 400);                 offScreenGraphics.setColor (Color.black);                 offScreenGraphics.drawString (scoreString, 20, 55);             }         }         if (snake [0] [0] < 20 || snake [0] [0] > 360 || snake [0] [1] < 60 || snake [0] [1] > 360)         {             JOptionPane.showMessageDialog (null, "You Have Died!");             numOfPieces = 1;             snake [0] [0] = 20;             snake [0] [1] = 60;             xChange = 0;             yChange = 0;             score = 0;             repaint ();         }         if (snake [0] [0] == prizeX && snake [0] [1] == prizeY)         {             numOfPieces++;             score++;             for (int count = 0 ; count < numOfPieces ; count++)             {                 if (snake [count] [0] == prizeX && snake [count] [1] == prizeY)                 {                     prizeX = (int) ((Math.random () * 18) + 1) * 20;                     prizeY = (int) ((Math.random () * 16) + 3) * 20;                 }             }         }     }     public static void main (String[] args)     {         new Snake ();     } }