mouseEntered will not execute

问题

I am trying to do a mouseEntered test to change a square colour however the MouseListener mouseEntered would not execute. The mouse is responding but only to clicks, pressed and release. So i am not sure what is going on. I hope you can help me point my problem thanks.

//Class
class RectangleClass extends JPanel{
    private int height;
    private int width;
    private boolean MouseEntered= false;
    private boolean MouseExit= false;
    private JPanel myPanel = new JPanel();
//Inner class with mouse Event
    class RectangleAdapter extends MouseAdapter{

        public void MouseEntered(MouseEvent e){
            System.out.println("MouseEntered"); 
            MouseEntered = true;
            repaint();
        }

        public void MouseExited(MouseEvent e){
            System.out.println("MouseExited");  
            MouseExit = true;
            repaint();
        }

    }
//constructor
    public RectangleClass(int height,int width){

        myPanel = this;
        this.height=height;
        this.width=width;
        this.addMouseListener(new RectangleAdapter());
    }
//paint graphic
    public void paint(Graphics g){
        super.paint(g);
        g.clearRect(0, 0, width, height);
        g.drawRect(0, 0, width, height);
        g.setColor(Color.YELLOW);

        if (MouseEntered){
            g.setColor(Color.CYAN);
            MouseEntered= false;
        }
        if (MouseExit){
            g.setColor(Color.orange);
            MouseExit= false;
        }
        g.fillRect(0, 0, width, height);
    }
}

public class RectangleContainer extends JFrame{

    public RectangleContainer(){
        setLayout(null);
        JPanel myPanel = new RectangleClass(100,100);
        myPanel.setBounds(50, 50, 200, 200);
        setSize(200,200);
        add(myPanel);
        setVisible(true);
    }

    public static void main(String args[]){
        new RectangleContainer();
    }
}

回答1:

You have started the mouseEntered method in your code with a capital M. Change it to lowercase m.

回答2:

You're not actually overriding the mouseEntered method of MouseAdapter, you need

@Override
public void mouseEntered(MouseEvent e) {

Adding @Override will let the compiler check that you are overriding the correct method. The same applies for mouseExited BTW.

Side Notes:

Don't use null layout - Always use a layout manager
For custom painting override paintComponent rather than paint
Java naming conventions indicate that all variables start with a lowercase letter which would make the variable MouseEntered mouseEntered

来源：https://stackoverflow.com/questions/15457160/mouseentered-will-not-execute

标签

java

swing

awt

mouselistener