java - Java 中的二维数组未正确更改

Question

在我正在从事的 Game Of Life 项目中，我有一个二维字节数组。该数组代表一个游戏板。问题是当我尝试访问数组时，它返回全零。但是，在我设置单元格的函数中，更改保存得很好。

这是类:

public class Game {
    int boardW;
    int boardH;
    Board board;
    public Game(int bW) {
        boardW = bW;
        boardH = bW;
        this.board = new Board(boardH, boardW);
    }

    private byte updateCell(int x, int y) {
        byte neighbors = 0;
        // Loop through 8 neighbors and count them
        for (byte offset_y = -1; offset_y < 2; offset_y++) {
            for (byte offset_x = -1; offset_x < 2; offset_x++) {
                // Make sure we don't check our current cell
                if (offset_x != 0 || offset_y != 0) {
                    byte newY = (byte) (y + offset_y);
                    byte newX = (byte) (x + offset_x);
                    // Roll over edge of board
                    if (y + offset_y < 0) {
                        newY = (byte) (boardH - 1);
                    }
                    else if (y + offset_y >= boardH) {
                        newY = 0;
                    }
                    if (x + offset_x < 0) {
                        newX = (byte) (boardW - 1);
                    }
                    if (x + offset_x >= boardW) {
                        newX = 0;
                    }
                    neighbors += this.board.getState(newX, newY);
                }
            }
        }
        if (neighbors < 2) {return 0;}
        if (neighbors > 3) {return 0;}
        if (neighbors == 3) {return 1;}
        return this.board.getState(x, y);
    }

    public Board gameTick() {
        Board nextTick = new Board(boardH, boardW);
        // Go through next iteration of cells
        for (int h = 0; h < boardH; h++) {
            for (int w = 0; w < boardW; w++) {
                nextTick.setState(w, h, updateCell(w, h));
            }
        }
        return nextTick;
    }

    public Board getBoard() {

        return this.board;
    }

    public void toggleCell(int x, int y, byte state) {
        this.board.setState(x, y, state);
    }
}

class Board {
    private final byte[][] board;
    final int height;
    final int width;

    public Board(int h, int w) {
        width = w;
        height = h;
        board = new byte[height][width];
    }

    public void setState(int x, int y, byte state) {
        board[y][x] = state;
    }

    public byte getState(int x, int y) {
        return board[y][x];
    }

    public byte[][] getData() {
        return board;
    }

    public void setData(byte[][] newBoard) {
        for (int x = 0; x<newBoard.length; x++) {
            for (int y = 0; y<newBoard.length; y++) {
                setState(x, y, newBoard[y][x]);
            }
        }
    }
}

这是怎么回事？

编辑:事实证明这是访问板的代码中的另一个问题，我已经解决了。感谢大家的帮助。

Answer 1

完全改变代码的设计。有一个包装类 Board，它封装(和隐藏)里面的二维数组(如果它必须是一个数组的话)。

public class Board {
    private final byte[][] board;

    public Board(int height, int width) {
        board = new byte[height][width];
    }

    public void setState(int x, int y, byte state) {
        board[y][x] = state;
    }

    public byte getState(int x, int y) {
        return board[y][x];
    }
}

然后创建 Board 类的实例并仅通过该实例访问状态。

因此，您可以安全地访问您的数据，并且您的设计可以在未来进行修改。你是例如免费开始添加有用的方法，例如

boolean isRowEmpty(int x)
boolean isColumnEmpty(int y)
void resetRow(int x)
void resetColumn(int y)
void reset()

所有这些都将在 Board 类的实例上很好地调用。您不会直接从业务逻辑代码访问数组，这是一种令人讨厌的做法。