Using Thread in Java to Create Animation, Example 3

Now, we are at a point to create animation on our canvas without using an image; doing it just by painting. Still we use the tick-tack technique between run() method and the other() method. Here we have to add a paint() method to create the desired object for us, we put a small red blob, an oval shape on the canvas, moving from left to right. The canvas is a java swing panel.

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package Forward; /** * * author Peter Jones */ public class Ex3Thread extends javax.swing.JFrame implements java.lang.Runnable{ /** Creates new form Ex3Thread */ public Ex3Thread() { super("Example 3!"); // A title for the frame aPanel = new javax.swing.JPanel(); setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE); setPreferredSize(new java.awt.Dimension(200, 100)); add(aPanel); pack(); start(); } /** Start when browser is loaded or button pushed. **/ public void start() { if (fThread == null){ fThread = new java.lang.Thread (this); fThread.start(); } } // start /** The thread loops to draw each frame.**/ public void run() { j=0; // Loop through animation frames while ( fThread != null){ // Sleep between frames try{ Thread.sleep (100); x+=3; paint(); } catch (InterruptedException e) { } // Now go to other frame other(); isDone(); //if (this.isDone()) fThread = null; } }// run ends // Your other frame comes here. public void other(){ // ++j; // Sleep between frames try{ Thread.sleep (200); aPanel.repaint(); // meanwhile repaint the panel. } catch (InterruptedException e) { } } /* Boolean allows you to terminate this thread, if you like, and go to other tasks. * I used it to provide a flag for counting. */ public boolean isDone() { boolean temp=false; if(j==COUNTS) { temp=true; j=0; x=10; } return temp; } //Create some graphic public void paint() { java.awt.Graphics g=aPanel.getGraphics(); g.setColor(java.awt.Color.red); g.fillOval(x, 25, 5, 5); } public static void main(String args[]) { new Ex3Thread().setVisible(true); } /* Variables declaration - do not modify * For simple GUI */ private javax.swing.JPanel aPanel; /* Variables declaration - do not modify * For thread animation */ int j=0; //counter int x=10; // X-coordinate of a point Thread fThread; final int COUNTS=50; // End of variables declaration }

Click here to see the application. If you save the "jar" file in your computer you can use "7z" decompression utility to extract source file and image files.