Platformer: Animated Player Sprite

Today we added our player sprites and animated them:

import greenfoot.*;  // (World, Actor, GreenfootImage, Greenfoot and MouseInfo)

/**
 * Write a description of class Player here.
 * 
 * @author (your name) 
 * @version (a version number or a date)
 */
public class Player extends Actor
{
    private int vSpeed = 0;
    private int acceleration = 1;
    private boolean jumping;
    private int jumpStrength = 16;
    private int speed = 4;
    
    private GreenfootImage run1r = new GreenfootImage("run1r.png");
    private GreenfootImage run2r = new GreenfootImage("run2r.png");
    private GreenfootImage run3r = new GreenfootImage("run3r.png");
    private GreenfootImage run4r = new GreenfootImage("run4r.png");
    private GreenfootImage run1l = new GreenfootImage("run1l.png");
    private GreenfootImage run2l = new GreenfootImage("run2l.png");
    private GreenfootImage run3l = new GreenfootImage("run3l.png");
    private GreenfootImage run4l = new GreenfootImage("run4l.png");
    private int frame = 1;
    private int animationCounter = 0;
    
    /**
     * Act - do whatever the Player wants to do. This method is called whenever
     * the 'Act' or 'Run' button gets pressed in the environment.
     */
    public void act() 
    {
        checkFall();
        checkKey();
        animationCounter++;
    }   
    
    public void checkKey()
    {
        if(Greenfoot.isKeyDown("space") && jumping == false)
        {
            jump();
        }
        if(Greenfoot.isKeyDown("right"))
        {
            moveRight();
        }
        if(Greenfoot.isKeyDown("left"))
        {
            moveLeft();
        }
    }
    
    public void moveRight()
    {
        setLocation(getX()+speed, getY());
        if(animationCounter % 4 == 0)
        {
        animateRight();
        }
    }
    
    public void animateRight()
    {
        if(frame == 1)
        {
            setImage(run1r);
        }
        else if(frame == 2)
        {
            setImage(run2r);
        }
        else if(frame == 3)
        {
            setImage(run3r);
        }
        else if(frame == 4)
        {
            setImage(run4r);
            frame = 1;
            return;
        }
        frame++;
    }
    
    public void moveLeft()
    {
        setLocation(getX()-speed, getY());
        if(animationCounter %4 == 0)
        {
        animateLeft();
    }
    }
    
    public void animateLeft()
    {
        if(frame == 1)
        {
            setImage(run1l);
        }
        else if(frame == 2)
        {
            setImage(run2l);
        }
        else if(frame == 3)
        {
            setImage(run3l);
        }
        else if(frame == 4)
        {
            setImage(run4l);
            frame = 1;
            return;
        }
        frame++;
    }
    
    public void fall()
    {
        setLocation(getX(), getY() + vSpeed);
        if(vSpeed <=9)
        {
            vSpeed = vSpeed + acceleration;
        }
        jumping = true;
    }
    
    public boolean onGround()
    {
        int spriteHeight = getImage().getHeight();
        int yDistance = (int)(spriteHeight/2) + 5;
        Actor ground = getOneObjectAtOffset(0, getImage().getHeight()/2, Platform.class);
        if(ground == null)
        {
            jumping = true;
            return false;
        }
        else
        {
            moveToGround(ground);
            return true;
        }
    }
    
    public void moveToGround(Actor ground)
    {
        int groundHeight = ground.getImage().getHeight();
        int newY = ground.getY() - (groundHeight + getImage().getHeight())/2;
        setLocation(getX(), newY);
        jumping = false;
    }
    
    public void checkFall()
    {
        if(onGround())
        {
            vSpeed = 0;
        }
        else
        {
            fall();
        }
    }
    
    public void jump()
    {
        vSpeed = vSpeed - jumpStrength;
        jumping = true;
        fall();
    }
}