can anyone post different varietals on how i could remove an object after adding it to the world?


import greenfoot.*; // (World, Actor, GreenfootImage, Greenfoot and MouseInfo) public class Yellowplayer2 extends Char { private int fallSpeed = 0; private int acceleration = 1; boolean isJumping=false; public void act() { move(); //manage the motion horizontally drop(); //manage the motion vertically start(); } private void start() { Actor first = getOneObjectAtOffset(0,0,End.class); if(first!=null) { Second h = new Second(); Greenfoot.setWorld(h); } Actor change = getOneObjectAtOffset(0,0,Change.class); if(change!=null) { Wall wall = new Wall(); getWorld().addObject(wall,29,215); getWorld().addObject(new Wallup(),61,240); getWorld().addObject(new Wallup(),301,242); getWorld().addObject(new Wall(),490,333); getWorld().addObject(new Change2(),484,309); } Actor Firstc = getOneObjectAtOffset(0,0,Firstc.class); if(Firstc!=null) { } Actor change2 = getOneObjectAtOffset(0,0,Change2.class); if(change2!=null) { [[[[[[HELPHERE]]]]] } Actor exit = getOneObjectAtOffset(0,0,Exit1.class); if(exit!=null) { // setImage("smallblock.png"); // Third a = new Third(); // Greenfoot.setWorld(a); }} public void drop(){ if(isJumping==true) jump(); else if(onGround()==false) { fall(); } else standOn(); } public boolean onGround(){ Object t1=(Object)getOneObjectAtOffset(-getImage().getWidth()/2+5, getImage().getHeight()/2 , Object.class); Object t2=(Object)getOneObjectAtOffset(getImage().getWidth()/2-5, getImage().getHeight()/2 , Object.class); if(t1!=null||t2!=null) return true; else return false; } public void standOn(){ Object t1=(Object)getOneObjectAtOffset(-getImage().getWidth()/2+5, getImage().getHeight()/2 , Object.class); Object t2=(Object)getOneObjectAtOffset(getImage().getWidth()/2-5, getImage().getHeight()/2 , Object.class); if(t1!=null) setLocation ( getX(), t1.getY()-t1.getImage().getHeight()/2-getImage().getHeight()/2+2); else if(t2!=null) setLocation ( getX(), t2.getY()-t2.getImage().getHeight()/2-getImage().getHeight()/2+2); fallSpeed=0; if (Greenfoot.isKeyDown("up")){ fallSpeed = -12; isJumping=true; } } public void fall(){ setLocation(getX(),getY() + fallSpeed); fallSpeed = fallSpeed + acceleration; } public void jump(){ setLocation(getX(),getY() + fallSpeed); fallSpeed = fallSpeed + acceleration; if(fallSpeed>=0) isJumping=false; Object t1=(Object)getOneObjectAtOffset(-getImage().getWidth()/2+5 ,-getImage().getHeight()/2, Object.class); Object t2=(Object)getOneObjectAtOffset(getImage().getWidth()/2-5 ,-getImage().getHeight()/2, Object.class); if (t1!=null) { setLocation ( getX(), t1.getY() + t1.getImage().getHeight()/2+getImage().getHeight()/2+1); fallSpeed=0; } else if(t2!=null){ setLocation ( getX(), t2.getY() + t2.getImage().getHeight()/2+getImage().getHeight()/2+1); fallSpeed=0; } } public void move(){ if (Greenfoot.isKeyDown("left")){ setLocation(getX()-7, getY()); } Object t=(Object)getOneObjectAtOffset(-getImage().getWidth()/2 ,0, Object.class); if (t!=null) setLocation ( t.getX()+t.getImage().getWidth()/2+getImage().getWidth()/2, getY() ); if (Greenfoot.isKeyDown("right")){ setLocation(getX()+7, getY()); } t=(Object)getOneObjectAtOffset(getImage().getWidth()/2 ,0, Object.class); if (t!=null) setLocation ( t.getX()-t.getImage().getWidth()/2-getImage().getWidth()/2, getY() ); } }
Wall wall = new Wall(); getWorld().addObject(wall,29,215); getWorld().addObject(new Wallup(),61,240); getWorld().addObject(new Wallup(),301,242); getWorld().addObject(new Wall(),490,333); getWorld().addObject(new Change2(),484,309);
getWorld().removeObjects(Wallup.class); getWorld().removeObjects(Change.class);