CODEWITHSUNDEEP
javaarrays
mr2k
mr2k

Reputation: 438

Accessing object-type methods from an object array java

My problem is I'm trying to make a console based chess game. Starting off with an Object array to hold the squares of the chess board.

class Chessboard {
    Object[][] board = new Object[10][10];

I fill it out perfectly with various if-sentences like this: 

for (int i = 0; i < 10; i++) {
    for (int j = 0;j < 10; j++) {
        if a position on a chess demands a specific piece:
                 board[i][j] = new ChessPiece(String firstLetterOfPiece, i, j);
        else fill in blanks:
                 board[i][j] = new ChessPiece(" ", i,j);
    }
}

Now, I have some find position methods in the ChessPiece class that just gives a compiler error when I try it from the class Chessboard.

What I do is: (to test)

System.out.println(board[2][4].getXposition());

I get "Cannot find symbol". What can I do to avoid this?

Upvotes: 0

Views: 118

Answers (2)

Chris
Chris

Reputation: 23171

Firstly, if your array will only ever contain ChessPiece objects, declare it as 

ChessPiece[][] board = new ChessPiece[10][10];

Secondly, since your array elements can be null, you'll want to do a null check before calling any methods:

if(board[2][4] != null)  System.out.println(board[2][4].getXPosition());

Upvotes: 0

corsiKa
corsiKa

Reputation: 82559

Well, you could "cast" it, for example: ((ChessPiece)(board[2][4])).getXposition()

But I would recommend doing something different: make a ChessSquare class that can hold a ChessPiece, or not.

Then go

ChessSquare square = board[2][4];
if(square.hasPiece()) {
    ChessPiece piece = square.getPiece();
    return piece.getXposition();
}

Upvotes: 1

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