The Java Boutique: Java Tutorial: Java by Example: Input Devices

import java.awt.*; import java.applet.*; public class Project30 extends Applet { Image Buffer; Graphics gBuffer; boolean pressedLeft, pressedRight, pressedUp, pressedDown; AudioClip mySound; public void init() { Buffer=createImage(size().width,size().height); gBuffer=Buffer.getGraphics(); try { mySound=getAudioClip(getCodeBase(),"sound.au"); } catch (Exception e){} } public boolean keyDown(Event e, int key) { if(key==Event.LEFT) pressedLeft=true; if(key==Event.RIGHT) pressedRight=true; if(key==Event.UP) pressedUp=true; if(key==Event.DOWN) pressedDown=true; if(key=='s'||key=='S') mySound.play(); repaint(); return true; } public boolean keyUp(Event e, int key) { pressedLeft=pressedRight=pressedUp=pressedDown=false; repaint(); return true; } public void drawStuff() { gBuffer.setColor(Color.blue); gBuffer.fillRect(0,0,size().width,size().height); gBuffer.setFont(new Font("Helvetica",Font.PLAIN,14)); gBuffer.setColor(Color.orange); //if we want to use "" inside a string, we have to mask it with \! gBuffer.drawString ("Click inside the applet, then try",50,30); gBuffer.drawString ("the cursor keys and the \"S\"-key!",45,50); //left int xl[] = {40,100,100}; int yl[] = {160,130,190}; if(pressedLeft) gBuffer.setColor(Color.yellow); else gBuffer.setColor(Color.red); gBuffer.fillPolygon(xl,yl,3); //right int xr[] = {260,200,200}; int yr[] = {160,130,190}; if(pressedRight) gBuffer.setColor(Color.yellow); else gBuffer.setColor(Color.red); gBuffer.fillPolygon(xr,yr,3); //up int xu[] = {120,150,180}; int yu[] = {110,60,110}; if(pressedUp) gBuffer.setColor(Color.yellow); else gBuffer.setColor(Color.red); gBuffer.fillPolygon(xu,yu,3); //down int xd[] = {120,150,180}; int yd[] = {210,260,210}; if(pressedDown) gBuffer.setColor(Color.yellow); else gBuffer.setColor(Color.red); gBuffer.fillPolygon(xd,yd,3); } public void update(Graphics g) { paint(g); } public void paint(Graphics g) { drawStuff(); g.drawImage (Buffer,0,0, this); } }