Cannot convert from String to (what should be another String)

Question

I'm trying to use enum to store a bunch of strings, but when I go to convert them into strings it doesn't work. I get the error "cannot convert from String to ChessSquare.SelectedPiece. I think it'll only be a little change, but I can't find what to change.

Here is my code:

package Logic;

import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JButton;


    //chess square class, 1 instance of which for each square in the grid
    @SuppressWarnings("serial")
    public class ChessSquare extends JButton {

        //instance variables for position and pieces
        public int posX;
        public int posY;
        public String currentPiece;
        public enum selectedPiece{
            NONE, PAWN, ROOK, KNIGHT, BISHOP, QUEEN, KING
        }
        selectedPiece piece;

        //load images and cast into icons
        BufferedImage buttonIcon = ImageIO.read(new File(piece));
            ImageIcon Icon = new ImageIcon(buttonIcon);
                BufferedImage 

        //constructor for chess squares
        public ChessSquare(int x, int y, double p) throws IOException {
            this.setIcon(Icon);
                setVisible(true);
            }

        //accessor method for position
        public void squarePos(int x, int y){
            this.posX = x;
            this.posY = y;
        }

        //accessor method for currentPiece
        public void cPiece(){
            this.currentPiece = piece;
        }

        //specify what each value of enum slectedPiece represents
        public void selectedPiece(){
            switch (piece){
                case NONE:
                        piece = "E:\\Eclipse\\ChessF\\src\\Images\\EmptySquare.jpg";
                case PAWN:
                        piece = "E:\\Eclipse\\ChessF\\src\\Images\\Pawn.jpg";
                case ROOK:
                        piece = "E:\\Eclipse\\ChessF\\src\\Images\\Rook.jpg";
                case KNIGHT:
                        piece = "E:\\Eclipse\\ChessF\\src\\Images\\Knight.jpg";
                case BISHOP:
                        piece = "E:\\Eclipse\\ChessF\\src\\Images\\Bishop.jpg";
                case QUEEN:
                        piece = "E:\\Eclipse\\ChessF\\src\\Images\\Queen.jpg";
                case KING:
                        piece = "E:\\Eclipse\\ChessF\\src\\Images\\King.jpg";
            }
        }
    }

`enum != String`. You can't just interchange types like that. — Sotirios Delimanolis, Mar 22 '13 at 15:09
I can't compile your code: `ImageIcon Icon = new ImageIcon(buttonIcon); BufferedImage` — Iswanto San, Mar 22 '13 at 15:11
Not answering your question but you really really should put break; and default: in your switch case. That would save you from hell. — cwhsu, Mar 22 '13 at 15:16
The problem is in your cPiece method. What exactly is your cPiece method supposed to do? — Aaron Kurtzhals, Mar 22 '13 at 15:18
FYI you can use / for the directory separator. The JVM will convert it to \ on Windows. — Steve Kuo, Mar 22 '13 at 19:57

score 2 · Answer 1 · answered Mar 22 '13 at 15:18

In Java, enum is a full fledged class... As such, you should put your enum operations (convert to/from string) inside it. For example:

    public enum SelectedPiece{
        NONE("E:\\Eclipse\\ChessF\\src\\Images\\EmptySquare.jpg"), 
        PAWN("E:\\Eclipse\\ChessF\\src\\Images\\Pawn.jpg"), 
        ROOK("E:\\Eclipse\\ChessF\\src\\Images\\Rook.jpg"), 
        KNIGHT("E:\\Eclipse\\ChessF\\src\\Images\\Knight.jpg"), 
        BISHOP("E:\\Eclipse\\ChessF\\src\\Images\\Bishop.jpg"), 
        QUEEN("E:\\Eclipse\\ChessF\\src\\Images\\Queen.jpg"), 
        KING("E:\\Eclipse\\ChessF\\src\\Images\\King.jpg");

        private String imageFilename;
        private ImageIcon image;

        private SelectedPiece( String imageFilename ) throws IOException {
            this.imageFilename = imageFilename;
            this.image = new ImageIcon(ImageIO.read(new File(piece)));
        }

        public String getImageFilename() {
            return imageFilename;
        }

        public ImageIcon getImage() {
            return image;
        }
    }

And so forth... Then just use the enum values where needed.

@SteveKuo, not saying that they shouldn't be, but how would that help? (curious, not challenging...) — Lucas, Mar 22 '13 at 19:57

score 1 · Answer 2 · answered Mar 22 '13 at 15:12

Enum is not a string. To convert between them, you need to use valueOf

E.g.,

selectedPiece.valueOf("ROOK");

Will return the enum selectedPiece.ROOK

When writing the enum, you can use a custom value, e.g.,

Public enum Piece {
  ROOK("Rook"),
  QUEEN("Queen")
}

score 0 · Answer 3 · answered Mar 22 '13 at 15:13

0

When you do this.currentPiece = piece; you're attempting to assign an enum type in a String object. It's impossible.

answered Mar 22 '13 at 15:13

Guillaume M

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score 0 · Answer 4 · answered Mar 22 '13 at 15:14

piece is of type selectedPiece (your enum)

You are not allowed to assign a String to it. Store your paths in another variable.

eg.:

String piecePath;
switch (piece){
                    case NONE:
                            piecePath = "E:\\Eclipse\\ChessF\\src\\Images\\EmptySquare.jpg";
 ...

score 0 · Answer 5 · answered Mar 22 '13 at 15:14

You should use the enum as a variable in the class to determine its type. You could simply add:

    public selectedPiece pieceType;

Then set the type somewhere in the object:

    pieceType = selectedPiece.ROOK;

Then you can do the switch statement using the enum to assign the string to the string variable.

The way you organize this is up to you.

Zeddy · Answer 6 · 2013-03-22T15:23:10.750

0

Maybe this is a case for using CONSTANTS?, after all if the graphic image for a pawn is always going to be the same image, doesn't that make it constant?

static final string IMAGE_NONE = "E:\\Eclipse\\ChessF\\src\\Images\\EmptySquare.jpg";
static final string IMAGE_PAWN = "E:\\Eclipse\\ChessF\\src\\Images\\Pawn.jpg";

and in your case statements

case PAWN:
  piece = IMAGE_PAWN

etc etc

edited Mar 22 '13 at 15:23

answered Mar 22 '13 at 15:17

Zeddy

2,079
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Java doesnt have [var](http://stackoverflow.com/questions/3443858/c-sharp-var-keyword-equivalent-in-java) – Lucas Mar 22 '13 at 15:20
I changed it static final string, Thank You for point out my mistake. – Zeddy Mar 22 '13 at 15:25

Cannot convert from String to (what should be another String)

6 Answers6