Dog class for Greenfoot lesson

dog.java

import greenfoot.*;  // (World, Actor, GreenfootImage, Greenfoot and MouseInfo)
import java.util.List;
import java.util.ArrayList;
/**
 * Write a description of class Dog here.
 * Dog was made for all the cute shiba inus in the world and to gain recognition for them.
 * @author (Caitlyn Oda) 
 * @version (6/27/18)
 */
public class Dog extends Animal
{
    private int delay;
    public GreenfootSound whistle = new GreenfootSound("sounds/whistle.mp3");
    
    private List<GreenfootImage> right = new ArrayList();
    private List<GreenfootImage> left = new ArrayList();
    
    String baseName;
    int maxFrame = 10;
    int currentFrame = 0;
    private int maxDelay = 3;
    
    public Dog()
    {
        
        for(int x = 0; x < maxFrame; x++){
            baseName = "Walk0"; 
            if(x == maxFrame - 1){
               baseName = "Walk";
            }
            GreenfootImage rightDog = new GreenfootImage("images/" + baseName + Integer.toString(x + 1) + ".png");
            rightDog.scale(230, 200);
            right.add(rightDog);
            GreenfootImage leftDog = new GreenfootImage("images/" + baseName + Integer.toString(x + 1) + ".png");
            leftDog.mirrorHorizontally();
            leftDog.scale(230, 200);
            left.add(leftDog);
        };
        
        GreenfootImage dogImage = getImage();
        int height = dogImage.getHeight();
        int width = dogImage.getWidth();
        dogImage.scale(230, 200);
        delay = 0;
    }
    
    public void act() 
    {
        checkKeys();
        moveVertical();
    }   
    
    public void checkKeys()
    {
        if(Greenfoot.isKeyDown("z")){
            whistle.play();
        }
        
        if(Greenfoot.isKeyDown("i")){
            whistle.stop();
        }
        
        if(Greenfoot.isKeyDown("right")){
            move(3);
            switchImage();
        }
        else if(Greenfoot.isKeyDown("left")){
            move(-3);
            switchImageLeft();
        }
    }
    
    public void moveVertical()
    {
        int y = getY();
        int x = getX();
        if(Greenfoot.isKeyDown("up")){
            y = y - 3;
            setLocation(x, y);
            switchImage();
        }
        if(Greenfoot.isKeyDown("down")){
            y = y + 3;
            setLocation(x, y);
            switchImage();
        }
    }
    
    public void switchImage()
    {
        if(delay > maxDelay){   
            if (currentFrame < maxFrame) {
                setImage(right.get(currentFrame));
                currentFrame++;
            }
            else {
                currentFrame = 0;
            }
            delay = 0;
        }
        else{
            delay = delay + 1;
        }   
    }
    
    public void switchImageLeft()
    {
        if(delay > maxDelay){
            
            if (currentFrame < maxFrame) {
                setImage(left.get(currentFrame));
                currentFrame++;
            }
            else {
                currentFrame = 0;
            }
            delay = 0;
        }
        else{
            delay = delay + 1;
        }
    }
}