我的鼠标听众似乎没有工作。 有人能帮我吗？ 我必须将球移动到单击鼠标的位置，但它不起作用

Question

This is the code but it is not working. I thought i added the right thing but the mouse listener is even responding. Much help is needed.

class Mouse implements MouseListener {
    /**
    * Moves the ball to the (x, y) location where the mouse has been clicked
    */
    public void mousePressed(MouseEvent e) {
        ball.setX(e.getX());
        ball.setY(e.getY());

        if (e.isMetaDown()) {
            ball.move(getX(), getY());
            repaint();
        }
        if (e.isShiftDown()) {
            ball.setRandomSpeed(20);
            ball.setLocation(Math.random(), Math.random());
            repaint();
        }
    }
}

It is not working as you can see. I don't know what is wrong.

Answer 1

You are working with the , right?

The problem is, that you invoke methods on the MouseEvent e that do not work like expected in your case. The Methods e.isMetaDown() and e.isShiftDown() check weather the Meta modfier or the Shift modifier is down on this event. I think you searches for a method to check if you pressed the left ( MouseEvent.BUTTON1 ) or right mouse button ( MouseEvent.BUTTON3 ). You can consult this page:

https://docs.oracle.com/en/java/javase/11/docs/api/java.desktop/java/awt/event/MouseEvent.html

to inform yoursef about the Methods that can be invoked on MouseEvent s.

You could try these two small changes. (But this code is not tested,.) If you want somebody to test the code, then please post a minimal reproducible example as @DontKnowMuchBut Getting Better already mentioned.

class Mouse implements MouseListener {
    /**
    * Moves the ball to the (x, y) location where the mouse has been clicked
    */
    public void mousePressed(MouseEvent e) {
        ball.setX(e.getX());
        ball.setY(e.getY());

        if (e.getButton().equals(MouseEvent.BUTTON1)) {
            ball.move(getX(), getY());
            repaint();
        }
        if (e.getButton().equals(MouseEvent.BUTTON2)) {
            ball.setRandomSpeed(20);
            ball.setLocation(Math.random(), Math.random());
            repaint();
        }
    }
}

I hope this is helpfull.