java如何在同一类的函数中使用构造函数中的二维数组变量

Question

public class GameField {
    public static final int SIZE=8;

    public GameField() {
        Pawn[][] field = new Pawn[SIZE][SIZE];
    }

    void set(Cell cell, Pawn neuvalue) {
        this.field[cell.getx][cell.gety] = neuvalue;
    }
}

我想用x和y设置单元格的值，但它不起作用。我该怎么修呢

Answer 1

如果要在类的多个方法中使用值，应将其定义为类属性：

public class GameField {
    // this is a constant class attribute determining the initial size of the field
    public static final int SIZE = 8;

    // what you need is this: a variable class attribute, the field itself
    private Pawn[][] field;

    public GameField() {
        // you can define the size of the field like this (without a new declaration)
        field = new Pawn[SIZE][SIZE];
    }

    void set(Cell cell, Pawn neuvalue) {
        this.field[cell.getx][cell.gety] = neuvalue;
    }
}

public class GameField {
    // this is a constant class attribute determining the initial size of the field
    public static final int SIZE = 8;

    ...

    // what you can do if you cannot change the current constructor, write an alternative
    public GameField(int width, int height) {
        field = new Pawn[width][height];
    }

    ...
}