More code fragments for Slick2d blog post

DemoSprite1.java

... 
private int x = 100; 
private int y = 100; 
private int dx = 1; 
private int dy = 1; 
private Image img = null;
...

DemoSprite2.java

...
public void init(GameContainer gc) throws SlickException 
{ 
	img = new Image("res/ball.png"); 
}
...

DemoSprite3.java

...
public void render(GameContainer gc, Graphics g) throws SlickException 
{ 
	img.draw(x, y);		 
}
... 

DemoSprite4.java

...
public void update(GameContainer gc, int delta) throws SlickException 
{ 
	if(x>gc.getWidth()-img.getWidth()) dx = -1; 
	if(x<0) dx = 1; 
	if(y>gc.getHeight()-img.getHeight()) dy = -1; 
	if(y<0) dy = 1;		 
	x = x+dx; 
	y = y+dy; 		 
}
...