enemytest.java

《J2ME Game Programming》随书光盘源代码

import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;

/**
 * An example that creates a player and enemy ship.
 * @author Martin J. Wells
 */
public class EnemyTest extends MIDlet implements CommandListener, Runnable
{
   private GameScreen gameScreen;
   private Command quit;
   private boolean running;

   /**
    * Constructor for the MIDlet create the GameScreen object, adds a quit
    * command and then create a thread to do our cycling and painting.
    */
   public EnemyTest()
   {
      // Construct a canvas
      gameScreen = new GameScreen();

      // And a way to quit
      quit = new Command("Quit", Command.EXIT, 2);
      gameScreen.addCommand(quit);
      gameScreen.setCommandListener(this);

      // Create the game thread.
      running = true;
      Thread t = new Thread(this);
      t.start();
   }

   /**
    * Runnable interface run method that cycles the ships and requests a repaint
    * of the Canvas.
    */
   public void run()
   {
      while (running)
      {
         gameScreen.repaint();
         gameScreen.cycle();

         try
         {
            // Simple timing - sleep for 100 milliseconds.
            Thread.sleep(100);
         }
         catch (InterruptedException e)
         {
         }

      }
   }

   /**
    * Handles Application Manager notification the MIDlet is starting (or
    * resuning from a pause). In this case we set the canvas as the current
    * display screen.
    * @throws MIDletStateChangeException
    */
   protected void startApp() throws MIDletStateChangeException
   {
      Display.getDisplay(this).setCurrent(gameScreen);
   }

   /**
    * Handles Application Manager notification the MIDlet is about to be paused.
    * We don't bother doing anything for this case.
    */
   protected void pauseApp()
   {
   }

   /**
    * Handles Application Manager notification the MIDlet is about to be
    * destroyed. We don't bother doing anything for this case.
    */
   protected void destroyApp(boolean unconditional)
           throws MIDletStateChangeException
   {
   }

   /**
    * The CommandListener interface method called when the user executes
    * a Command, in this case it can only be the quit command we created in the
    * consutructor and added to the Canvas.
    * @param command The command that was executed.
    * @param displayable The displayable that command was embedded within.
    */
   public void commandAction(Command command, Displayable displayable)
   {
      try
      {
         if (command == quit)
         {
            running = false;
            destroyApp(true);
            notifyDestroyed();
         }
      }

      catch (MIDletStateChangeException me)
      {
         System.out.println(me + " caught.");
      }
   }

}