请你按照下列要求写个反应碰撞的程序It would be very useful to write this section of code as a separate method private GObject getCollidingObject() that returns the object involved in the collision, if any, and null otherwise. You could then use it in a declaration like GObject collider = getCollidingObject(); which assigns that value to a variable called collider. – 7 – From here, the only remaining thing you need to do is decide what to do when a collision occurs. There are only two possibilities. First, the object you get back might be the paddle, which you can test by checking if (collider == paddle) . . . If it is the paddle, you need to bounce the ball so that it starts traveling up. If it isn’t the paddle, the only other thing it might be is a brick, since those are the only other objects in the world. Once again, you need to cause a bounce in the vertical direction, but you also need to take the brick away. To do so, all you need to do is remove it from the screen by calling the remove method.

以下是一个反应碰撞的程序，包括了一个私有方法 getCollidingObject()，用于返回参与碰撞的对象，如果没有则返回 null。在检测到碰撞时，根据返回的对象决定下一步的操作，如果是球拍，则将球弹起；如果是砖块，则将球弹起并移除砖块。

private GObject getCollidingObject() {
    if (getElementAt(ball.getX(), ball.getY()) != null) {
        return getElementAt(ball.getX(), ball.getY());
    } else if (getElementAt(ball.getX() + BALL_RADIUS * 2, ball.getY()) != null) {
        return getElementAt(ball.getX() + BALL_RADIUS * 2, ball.getY());
    } else if (getElementAt(ball.getX(), ball.getY() + BALL_RADIUS * 2) != null) {
        return getElementAt(ball.getX(), ball.getY() + BALL_RADIUS * 2);
    } else if (getElementAt(ball.getX() + BALL_RADIUS * 2, ball.getY() + BALL_RADIUS * 2) != null) {
        return getElementAt(ball.getX() + BALL_RADIUS * 2, ball.getY() + BALL_RADIUS * 2);
    } else {
        return null;
    }
}

GObject collider = getCollidingObject();
if (collider != null) {
    if (collider == paddle) {
        vy = -vy;
    } else {
        vy = -vy;
        remove(collider);
    }
}