public void turn(int x, int y)//翻開
    {
        buttons[x][y].setBackground(Color.LIGHT_GRAY);
        if(aroundBombNum[x][y]>0)
            buttons[x][y].setText(Integer.toString(aroundBombNum[x][y]));
        isTurned[x][y] = true;
        isPressed[x][y] = true;
    }