Tutorials : Java by Example : Section 4 :

Functions and Arrays

Random Colors and Arrays - Con't

//Sourcecode import java.awt.*; import java.applet.*; public class Project17 extends Applet implements Runnable { Image Buffer; Graphics gBuffer; //declare an array variable to hold our Colors Color myColors[]; Thread runner; public void init() { //create off-screen image we can draw to Buffer=createImage(size().width,size().height); gBuffer=Buffer.getGraphics(); //arrays are real objects, we have to declare them with "new" myColors = new Color[100]; } public void getNewColors() { for(int i=0;i<100;i++) { int red=(int)(Math.random()*255); int green=(int)(Math.random()*255); int blue=(int)(Math.random()*255); //fill our array with random colors myColors[i]=new Color(red, green, blue); } } public void start() { if (runner == null) { runner = new Thread (this); runner.start(); } } public void stop() { if (runner != null) { runner.stop(); runner = null; } } public void run() { while(true) { //halt the thread for 1000 ms here try {runner.sleep(1000);} catch (Exception e) { } //get new colors every second getNewColors(); repaint(); } } public void update(Graphics g) { paint(g); } public void drawColors() { //draw tiles with random colors //we use two nested loops to do this: int i=0; for(int x=0;x<300;x+=30) for(int y=0;y<300;y+=30) { int red=(int)(Math.random()*255); int green=(int)(Math.random()*255); int blue=(int)(Math.random()*255); gBuffer.setColor(myColors[i]); gBuffer.fillRect(x,y,60,60); //increment the index of our array here i++; } } public void paint (Graphics g) { drawColors(); //copy the buffer to the screen g.drawImage (Buffer,0,0, this); } }

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