Question

我是开发国际象棋应用程序的初学者“开发者”。

InGameActivity类中有一个名为currentBoardState的变量public static。每个ChessPiece都有一个boolean[][] possibleMoves。以下方法将采用possibleMoves并确定是否有任何移动会导致玩家对其进行检查并将其设置为假，因为它不再是可能的移动。

@Override
public void eliminateMovesThatPutYouInCheck() {
    ChessPiece[][] originalBoard = InGameActivity.currentBoardState;
    final ChessPiece emptyPiece = new EmptyPiece(Color.EMPTY);
    final ChessPiece tempKnight = new Knight(side);
    //This block eliminates moves that will cause a player
    //to put him/her self in check.
    InGameActivity.currentBoardState[x][y] = emptyPiece;
    for (int i = 0; i < 8; i++) {
        for (int j = 0; j < 8; j++) {
            if (possibleMoves[i][j] == true) {
                tempKnight.x = i;
                tempKnight.y = j;
                InGameActivity.currentBoardState[i][j] = tempKnight;
                if (InGameActivity.isPlayerInCheck(side)) {
                    possibleMoves[i][j] = false;
                }
                InGameActivity.currentBoardState[i][j] = emptyPiece;
            }
        }
    }
    InGameActivity.currentBoardState = originalBoard;
}

问题是，我的currentBoardState变量搞砸了，我不知道为什么，我已经保存了值，然后在方法结束时重置它为什么会丢失它的值？

编辑：如果您需要，这是isPlayerInCheck方法，谢谢。

public static boolean isPlayerInCheck(Color side) {
        List<boolean[][]> opponentsMoves = new ArrayList<boolean[][]>();
        int xKing = -1;
        int yKing = -1;

        if (side.equals(Color.WHITE)) {
            xKing = whiteKing.x;
            yKing = whiteKing.y;
        } else {
            xKing = blackKing.x;
            yKing = blackKing.y;
        }

        if (side.equals(Color.WHITE)) {
            for (int i = 0; i < 8; i++) {
                for (int j = 0; j < 8; j++) {
                    if (currentBoardState[i][j].isBlack()) {
                        opponentsMoves.add(currentBoardState[i][j].possibleMoves);
                    }
                }
            }
            for (boolean[][] b : opponentsMoves) {
                for (int i = 0; i < 8; i++) {
                    for (int j = 0; j < 8; j++) {
                        if (b[xKing][yKing] == true) {
                            return true;
                        }
                    }
                }
            }
            return false;

        } else {
            for (int i = 0; i < 8; i++) {
                for (int j = 0; j < 8; j++) {
                    if (currentBoardState[i][j].isWhite()) {
                        opponentsMoves.add(currentBoardState[i][j].possibleMoves);
                    }
                    if (currentBoardState[i][j].isBlack() && currentBoardState[i][j].getType().equals(Type.KING)) {
                        xKing = currentBoardState[i][j].x;
                        yKing = currentBoardState[i][j].y;
                    }
                }
            }
            for (boolean[][] b : opponentsMoves) {
                for (int i = 0; i < 8; i++) {
                    for (int j = 0; j < 8; j++) {
                        if (b[xKing][yKing] == true) {
                            return true;
                        }
                    }
                }
            }
            return false;

        }
    }

另外，我理解并理解我的代码效率可能非常低，而且国际象棋的设计很糟糕，但这并不是我现在所关注的。

Answer 1

我假设messed up你的意思是currentBoardState变量未被“重置”到原始主板上。

这是由于这一行：

ChessPiece[][] originalBoard = InGameActivity.currentBoardState;

将当前电路板状态的引用传递给变量originalBoard。

当您修改currentBoardState时，由于originalBoard变量指向同一个对象，因此它也会被修改。

将数组复制到originalBoard变量，如：

ChessPiece[][] originalBoard = new ChessPiece[InGameActivity.currentBoardState.length][];
for(int i = 0; i < InGameActivity.currentBoardState.length; i++){
    ChessPiece[] pieces = InGameActivity.currentBoardState[i];
    int len = pieces.length;
    originalBoard[i] = new ChessPiece[len];
    System.arraycopy(pieces, 0, originalBoard[i], 0, len);
}

//Rest of code here...

仅当您通过值进行复制时，才会存在实际的数据副本。忽略原始类型和一些不可变数据，使用赋值运算符=仅将RHS的引用分配给LHS。

Answer 2

如果我正确理解您的代码，我认为您需要将原始代码复制到新数组中，例如：

ChessPiece[][] originalBoard = Arrays.copyOf(
    InGameActivity.currentBoardState, InGameActivity.currentBoardState.length);

这可以防止修改原始数组。

Answer 3

你有问题：

if (possibleMoves[i][j]) 
{ 
    tempKnight.x = i;
    tempKnight.y = j;
    InGameActivity.currentBoardState[i][j] = tempKnight;
    if (InGameActivity.isPlayerInCheck(side))
    {
       possibleMoves[i][j] = false;
    }
    /** whatever was before next line resets the value at i,j: puts empty piece here */
    InGameActivity.currentBoardState[i][j] = emptyPiece;
}

2d不保留值的对象数组

3 个答案: