Question

我确定我错过了一些愚蠢的话，这是我的代码：

public class clearBlankGrid {

    public static void main(String args[]) {

        Monster myMonster = new Monster(10,10,5,5,1);
        MonsterGUI myGUI = new MonsterGUI(myMonster);

        if (myMonster.getRows() > 0) {   
            // 0 = North, 1 = East, 2 = South, 3 = West
            myMonster.setFacing(3);
            myMonster.setIcon();
        }

    }

    public static void keepClearing() {

        myMonster.isGridCleared(); // Cannot find symbol 'myMonster'

    }

}

Answer 1

myMonster如果要在keepClearing方法（静态）中访问它，则需要是静态成员。

注意：作为参考，您还可以通过实际实例化Monster类来避免使clearBlankGrid成员静态。 Monster可以是clearBlankGrid的实例变量，这意味着keepClearing方法不再必须是静态的。

public class clearBlankGrid {

   private Monster myMonster;
   private MonsterGUI myGUI;

   public void run() {
       myMonster = new Monster(10,10,5,5,1);
       myGUI = new MonsterGUI(myMonster);

       if (myMonster.getRows() > 0) {   
            // 0 = North, 1 = East, 2 = South, 3 = West
            myMonster.setFacing(3);
            myMonster.setIcon();
        }
   }

    public void keepClearing() {
        myMonster.isGridCleared();
    }

    public static void main(String args[]) {
        clearBlankGrid blankGrid = new clearBlankGrid();
        blankGrid.run();
    }
}

Answer 2

您需要将对象放在静态字段中。

Answer 3

让myMonster成为static班级成员：

public class clearBlankGrid {

    private static Monster myMonster;

    public static void main(String args[]) {

        myMonster = new Monster(10,10,5,5,1);
        // ...

    }
}

Answer 4

public class clearBlankGrid {

    // I made this static because you access it via a static method.  
    // If you make it a class member, as Greg Hewgill suggested, then 
    // change the method that uses it to be non-static
    private static  Monster myMonster = new Monster(10,10,5,5,1);


    public static void main(String args[]) {

        MonsterGUI myGUI = new MonsterGUI(myMonster);

        if (myMonster.getRows() > 0) {   
            // 0 = North, 1 = East, 2 = South, 3 = West
            myMonster.setFacing(3);
            myMonster.setIcon();
        }

    }

    public static void keepClearing() {

        myMonster.isGridCleared(); // Cannot find symbol 'myMonster'

    }
}

如何从另一个方法访问我在main方法中实例化的对象？

4 个答案: