fullcanvastest.java

《J2ME Game Programming》随书光盘源代码

import com.nokia.mid.ui.FullCanvas;
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
import java.util.Random;

/**
 * An example that demonstrates the use of the Nokia UI FullCanvas class.
 * You must have the nokia UI class files on your classpath and run this example
 * on a Nokia emulator (such as the 7210).
 * @author Martin J. Wells
 */
public class FullCanvasTest extends MIDlet
{
   private MyCanvas myCanvas;

   /**
    * An inner class which extends from the com.nokia.mid.ui.FullCanvas and
    * implements a random rectangle drawer.
    */
   class MyCanvas extends FullCanvas
   {
      private Random randomizer = new Random();

      /**
       * A method to obtain a random number between a miniumum and maximum
       * range.
       * @param min The minimum number of the range
       * @param max The maximum number of the range
       * @return
       */
      private int getRand(int min, int max)
      {
         int r = Math.abs(randomizer.nextInt());
         return (r % (max - min)) + min;
      }

      /**
       * Canvas class paint implementation where we draw the some random
       * rectangles.
       * @param graphics The graphics context to draw to
       */
      protected void paint(Graphics graphics)
      {
         for (int i = 10; i > 0; i--)
         {
            graphics.setColor(getRand(1, 254), getRand(1, 254), getRand(1, 254));
            graphics.fillRect(0, 0, i * (getWidth() / 10), i * (getHeight() / 10));
         }
      }
   }

   /**
    * MIDlet class which constructs an instance of our custom FullCanvas.
    */
   public FullCanvasTest()
   {
      myCanvas = new MyCanvas();
   }

   /**
    * Called by the Application Manager when the MIDlet is starting or resuming
    * after being paused. In this example it acquires the current Display object
    * and uses it to set the Form object created in the MIDlet constructor as
    * the active Screen to display.
    * @throws MIDletStateChangeException
    */
   protected void startApp() throws MIDletStateChangeException
   {
      Display.getDisplay(this).setCurrent(myCanvas);
   }

   /**
    * Called by the MID's Application Manager to pause the MIDlet. A good
    * example of this is when the user receives an incoming phone call whilst
    * playing your game. When they're done the Application Manager will call
    * startApp to resume. For this example we don't need to do anything.
    */
   protected void pauseApp()
   {
   }

   /**
    * Called by the MID's Application Manager when the MIDlet is about to
    * be destroyed (removed from memory). You should take this as an opportunity
    * to clear up any resources and save the game. For this example we don't
    * need to do anything.
    * @param unconditional if false you have the option of throwing a
    * MIDletStateChangeException to abort the destruction process.
    * @throws MIDletStateChangeException
    */
   protected void destroyApp(boolean unconditional) throws MIDletStateChangeException
   {
   }
}