Java:从类中打印/返回数组

Question

我为宾果游戏创建了一个类。我收到一条错误消息，提示“预期为‘class’”。我怎样才能将数组中的值返回给主启动器？任何其他评论也会有所帮助。谢谢。

import java.util.Random;
public class Card
{
    Random generator = new Random();

    private final int BOARDMAX = 4; 
    private final int NUMMAX = 59;
    int i, j, m, n;
    private int [][] ArrayBoard = new int[BOARDMAX][BOARDMAX];
    String [][] StrArrayBoard = new String [BOARDMAX][BOARDMAX];

    public void RandomNumGenerator()
    {
        for (i = 0; i<BOARDMAX; i++)
        {
            for (j = 0; j<BOARDMAX; j++)
            {
                ArrayBoard[i][j] = generator.nextInt (NUMMAX+1);
            }
        }

    }   

    public String ShowBoard()
    {
        for (i = 0; i<BOARDMAX; i++)
        {
            for (j = 0; j<BOARDMAX; j++)
            {
                m=i;
                n=j;
                if (j != BOARDMAX)
                    StrArrayBoard[m][n] = ArrayBoard[m][n] + "  ";
                else
                    StrArrayBoard[m][n] = ArrayBoard[m][n] + "  \n";
            }
        }
        return StrArrayBoard[i][j];
    }

    public void ShowMark()
    {
        for (i = 0; i<BOARDMAX; i++)
        {
            for (j = 0; j<BOARDMAX; j++)
            {
                if (CardCheck [i][j] == 1)
                    StrArrayBoard[i][j] = ArrayBoard[i][j] + "* ";
                else
                    StrArrayBoard[i][j] = ArrayBoard[i][j] + "  ";  
                if (j == BOARDMAX)
                    ArrayBoard[i][j] = ArrayBoard[i][j] + "\n";
            }
        }
    }

    public String toString()
    {
        return ArrayBoard[][];
    }
}

Answer 1

使用 toString() 您需要返回一个 String 对象，但实际上您试图返回一个 int[][]。 ShowBoard 也是如此，您尝试返回一个不兼容类型的字符串数组。

修复方法如下:

public String ShowBoard() {
  // your code to populate StrArrayBoard

  StringBuilder boardBuilder = new StringBuilder();
  for (String[] row:StrArrayBoard)
    for (String cell:row)
      sb.append(cell);
  return boardBuilder.toString();
}

public String toString() {
  return ShowBoard();
}

---

我建议重构代码并重命名方法和字段:

ShowBoard()  -->  getBoardAsString()
ArrayBoard   -->  arrayBoard
StrArrayBoard --> strArrayBoard

并且不需要将 StrArrayBoard 声明为字段(类成员)，因为您只需要在 ShowBoard 方法中使用它。在那里将其声明为局部变量。