Need help getting height of image (Possible Inheritance Problem)

问题

Ok so this is the KernelHandler Class

public class KernelHandler extends ImageHandler

I'm getting a cannot find method getWidth()

I know it has something to do with inheritance, but I need help, please

//Heres the contructor

 public KernelHandler(String nameOfFile)
{
   super(nameOfFile);


    }

// here's the super constructor
public ImageHandler(String  nameOfFile){


     URL imageURL = getClass().getClassLoader().getResource(nameOfFile);
    try
    {
     myImage = ImageIO.read(imageURL);
    }
    catch ( IOException e )
    {
        System.out.println( "image missing" );
    }

// Here's the method were trying to use

public static int numOfRedBoxes(String nameOfImg)

    {
        KernelHandler myHand = new KernelHandler(nameOfImg);
        for(int i = 0; i < myHand.getWidth(); i++)

            for(int j = 0; j < myHand.getHeight(); j++){
                if(img.getRGB(i, j) == red){
                    numOfRedBoxes++;
               }   
            }
       }
      return numOfRedBoxes;
   }

回答1:

getWidth() should not have private access in ImageHandler (or package private access if both classes are in different packages). Could you check that?

Simply put, getWidth() should be prefixed with public or protected.

回答2:

Is there a method named getWidth() in ImageHandler? I have seen some implementations of this class that do not. That could be another reason why it is not accessible.

回答3:

Try changing the type of myHand to that of the super class , it would be something like:

ImageHandler myHand = new KernelHandler(nameOfImg);

来源：https://stackoverflow.com/questions/5651499/need-help-getting-height-of-image-possible-inheritance-problem