使用Gridworld的棋子游戏(Java)

Question

我一直在使用Gridworld在Eclipse中创建一个Checker游戏。到目前为止，我只是在修改红片。我的目标是能够移动()块，让他们选择是跳还是跳。显然，跳跃(即当该块移动到相反颜色的一块，然后将其从网格中移除)优先于步进。我的问题是，每当我试图移动前两列或最后两列中的部分时，我就会得到一个非法的越界错误。有人能帮我解决这个问题吗？请谢谢你。

import java.awt.Color;
import info.gridworld.actor.Actor;
import info.gridworld.actor.Bug;
import info.gridworld.actor.Critter;
import info.gridworld.actor.Flower;
import info.gridworld.grid.Grid;
import info.gridworld.grid.Location;

public class RedPieces extends Bug {
boolean jumped;

public RedPieces() {
    setColor(Color.red);
    setDirection(180);
    jumped = false;
}

public boolean canMove() {
    Grid<Actor> gr = getGrid();
    if (gr == null)
        return false;
    Location loc1 = getLocation();
    if (getGrid().get(new Location(loc1.getRow() + 1, loc1.getCol() - 1)) == null || 
        getGrid().get(new Location(loc1.getRow() + 1, loc1.getCol() - 1)).getColor() == Color.black || 
        getGrid().get(new Location(loc1.getRow() + 1, loc1.getCol() + 1)) == null || 
        getGrid().get(new Location(loc1.getRow() + 1, loc1.getCol() + 1)).getColor() == Color.black) {
        return true;
    }
    return false;
}

public boolean jump2(Location loc){
    Grid<Actor> gr = getGrid();
    if (gr == null)
        return false;
    Location jump1 = new Location(loc.getRow() + 2, loc.getCol() - 2);
    Location jump2 = new Location(loc.getRow() + 2, loc.getCol() + 2);

    if( (gr.isValid(jump1)) && 
        (gr.get(jump1) == null) && 
        (gr.get(jump2) == null) && 
        (gr.get(new Location(loc.getRow() + 1, loc.getCol() -1)) instanceof BlackPieces) && 
        ((gr.get(new Location(loc.getRow() + 1, loc.getCol() + 1)) == null) || 
         (gr.get(new Location(loc.getRow() + 1, loc.getCol() + 1))) instanceof RedPieces))
    {
        gr.get(new Location(loc.getRow() + 1, loc.getCol() -1)).removeSelfFromGrid();
        moveTo(jump1);
        return true;
    }
    else if( (gr.isValid(jump2)) && 
             (gr.get(jump2) == null) && 
             (gr.get(jump1) == null) && 
             (gr.get(new Location(loc.getRow() + 1, loc.getCol() +1)) instanceof BlackPieces) && 
             ((gr.get(new Location(loc.getRow() +1, loc.getCol() - 1)) == null) || 
              (gr.get(new Location(loc.getRow() + 1, loc.getCol() -1)) instanceof RedPieces)))
    {
        gr.get(new Location(loc.getRow() + 1, loc.getCol() +1)).removeSelfFromGrid();
        moveTo(jump2);
        return true;
    }
    else if((gr.isValid(jump1) && gr.get(jump1) == null) && 
            (gr.isValid(jump2) && gr.get(jump2) != null))
    {
        if(gr.get(new Location(loc.getRow() + 1, loc.getCol() -1)) instanceof BlackPieces)
        {
            gr.get(new Location(loc.getRow() + 1, loc.getCol() -1)).removeSelfFromGrid();
            moveTo(jump1);
            return true;
        }
    }
    else if((gr.isValid(jump2) && gr.get(jump2) == null) && 
            (gr.isValid(jump1) && gr.get(jump1) != null))
    {
        if(gr.get(new Location(loc.getRow() + 1, loc.getCol() +1)) instanceof BlackPieces)
        {
            gr.get(new Location(loc.getRow() + 1, loc.getCol() +1)).removeSelfFromGrid();
            moveTo(jump2);
            return true;
        }
    }

    return false;
}

public void move() {
    Grid<Actor> gr = getGrid();
    if (gr == null)
        return;

    Location loc = getLocation();
    Location next1 = new Location(loc.getRow() + 1, loc.getCol() - 1);
    Location next2 = new Location(loc.getRow() + 1, loc.getCol() + 1);
    if (jump2(loc) == false) {
        if (gr.isValid(next2) && gr.get(next2) == null && 
            gr.isValid(next1) && gr.get(next1) != null)
        {
            moveTo(next2);
        }
        else if (gr.isValid(next1) && gr.get(next1) == null && 
                 gr.isValid(next1) && gr.get(next2) != null)
        {
            moveTo(next1);
        }
        else if (gr.isValid(next1) && gr.get(next1) == null && 
                 gr.isValid(next2) && gr.get(next2) == null)
        {
            moveTo(randomLoc(next1, next2));
        }
        else
            return;
    }
}

public static Location randomLoc(Location loc1, Location loc2) {
    double num = Math.random();
    if (num < 0.5)
        return loc1;
    else
        return loc2;
}

public void act() {
    if(canMove()) move();
}
}

Answer 1

必须重新格式化代码以获得更好的可读性。通过这样做，我发现了一些潜在的bug。

• 在jump2()方法中，第二个if语句不检查jump2的有效性。这可能是在gr.get(jump2 == null)条件下if语句中出现异常的原因。
• 同样的逻辑也适用于后续的else if语句。这一次，您没有检查jump1的有效性。
• 在move()方法(第一个else if )中，您只检查next1的有效性两次，这似乎是一个错误。请在您的问题中重新格式化的代码中找到它。

总的来说，我认为您需要尽可能简单(可读)地修改if条件。重新格式化也会有帮助。

增加了两件小事。

• 在canMove()方法中，只在第一个if语句处使用gr。在第二个getGrid()语句中使用的是gr而不是gr。
• 您能避免每次在new Location语句中获取网格时都执行if吗？你在使用这些网格时没有检查它们的有效性。你确定它们是有效的吗？您可以在方法的开头创建它们，检查它们的有效性，并在if语句中使用它们。它也可能有助于if语句的可读性。

添加了更多的jump2()方法简化示例

下面的代码将忽略列的另一端(无效、空或红段)。这是基于我的假设，当一方有效跳过一块黑色物体时，其他方面的情况并不重要。

public boolean jump2(Location loc){
    Grid<Actor> gr = getGrid();
    if (gr == null)
        return false;

    Location jump1 = new Location(loc.getRow() + 2, loc.getCol() - 2);
    Location jump2 = new Location(loc.getRow() + 2, loc.getCol() + 2);
    Location adjacent1 = new Location(loc.getRow() + 1, loc.getCol() - 1);
    Location adjacent2 = new Location(loc.getRow() + 1, loc.getCol() + 1);

    // try one column
    if( gr.isValid(jump1))
    {
        if( (gr.get(jump1) == null) && 
            (gr.get(adjacent1) instanceof BlackPieces))
        {
            gr.get(adjacent1).removeSelfFromGrid();
            moveTo(jump1);
            return true;
        }
    }

    // try the other column
    if( gr.isValid(jump2))
    {
        if( (gr.get(jump2) == null) && 
             (gr.get(adjacent2) instanceof BlackPieces))
        {
            gr.get(adjacent2).removeSelfFromGrid();
            moveTo(jump2);
            return true;
        }
    }

    return false;
}