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Thread: Pretty new to Java can someone help with an addObject() problem?

  1. #1
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    Default Pretty new to Java can someone help with an addObject() problem?

    Hi I'm pretty knew to programming and I have an assignment which I've been working on but I am stuck

    I have to create a 'space invaders' style game, and I've got some basics working. I wanted to add a boss enemy, which appears when all other enemies have been destroyed. It kind of works, only the program spawns a seemingly infinite amount of the boss which then creates a 'wipe' effect across the top of the screen.
    Here is my code:
    import greenfoot.*; // (World, Actor, GreenfootImage, Greenfoot and MouseInfo)
    import java.util.List;
     
     
    public class Space extends World
    {
     
         /**
         * Constructor for objects of class Space.
         *
         */
         public Space()
         {
              // Create a new world with 200x250 cells with a cell size of 3x3 pixels.
              super(200, 250, 3);
              //add class with starstreaks
              addObject(new EmptyBox(),1,1);
              //add player character
              addObject(new Player(), 100, 228);
     
              //add 4 romulan enemies row 1
              for(int i=0; i<4; i++){
                   addObject(new Romulan(), (25 + 50 * i), 15);
              }
     
              //add 3 klingon enemies row 2
              for(int i=0; i<3; i++){
                   addObject(new Klingon(), (50 + 50 * i), 40);
              }
     
              //add 4 romulan enemies row 3
              for(int i=0; i<4; i++){
                   addObject(new Romulan(), (25 + 50 * i), 65);
              }
     
              //add 3 klingon enemies row 4
              for(int i=0; i<3; i++){
                   addObject(new Klingon(), (50 + 50 * i), 90);
              }
     
              //add 3 shields
              for(int i=0; i<3; i++){
                   addObject(new Shield(), (30 + 70 * i), 180);
              }
         }
     
         [B]public void act(){
     
              List<Enemy> enemies = getObjects(Enemy.class);
     
              if(enemies.size()==0 ){
                   addObject(new Borg(), 100, 30 );
              }
         }[/B]
    }

    I believe the part in bold is the problem, but I dont know why. Klingon and Romulan are subclasses of the Enemy class. The Borg class is it's own seperate class, but with the exact same functions as Enemy. I made it seperate as I figured it would keep respawning if it was a subclass of Enemy.


    Any ideas?
    Last edited by helloworld922; November 1st, 2009 at 12:07 PM.


  2. #2
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    Default Re: Pretty new to Java can someone help with an addObject() problem?

    Its ok, after more than an hour I've got it.
    I simply added private int bossValue = 0; at the beginning and then changed act to this:
    public void act(){
     
    List<Enemy> enemies = getObjects(Enemy.class);
     
     
    if(enemies.size()==0 && bossValue==0 ){
    //for(int i=0; i<1; i++){
     
    addObject(new Borg(), 100, 30 );
    bossValue =1;
    //}
    }
    }
    Last edited by helloworld922; November 1st, 2009 at 04:43 PM.

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