Question

我需要一个检查鼠标光标是否在组件上的函数。这些组件将是JButton，JTextField和JLabel。我试过以下代码

@Override
    public void paintComponent(Graphics g){
        super.paintComponent(g);
        boolean noDraw = false;

        if(this.getWidth() > mX && mX > 0){
            if( this.getHeight() > mY && mY > 0){
               components = this.getComponents();
               if( components != null){
                   for(int i = 0; i < components.length; ++i){
                      if( components[i].contains(mX, mY)){
                          noDraw = true;
                          break;
                      }
                   }
               }
               if(noDraw == false )
               {
                   Cicle.draw(g);
               }
            }
        }

    }

Answer 1

Java中有一个名为Mouse Listener的函数，您可以使用它。您可以单独将它添加到组件中，然后当鼠标越过组件时，将发生MouseEvent。例如，如果您有JButton名为yourComponent，则可以将Mouse Listener添加到组件中。

yourComponent.addMouseListener(new CustomMouseListener());

class CustomMouseListener implements MouseListener
{
    @Override
    public void mouseClicked(MouseEvent e){}

    @Override
    public void mouseEntered(MouseEvent e)
    {
        //Mouse is over component
        Object source = e.getSource();
        if (source instanceof JButton) {
            System.out.println("Mouse is over a JButton");
        }

        if (source instanceof JTextField) {
            System.out.println("Mouse is over a JTextField");
        }

        if (source instanceof JLabel) {
            System.out.println("Mouse is over a JLabel");
        }

        Sysem.out.println("Mouse is over "+ e.getComponent().getClass().getName());
    }

    @Override
    public void mouseExited(MouseEvent e)
    {
         //Mouse is not over component
         Sysem.out.println("Mouse is not over "+ e.getComponent().getClass().getName()+" anymore");
    }

    @Override
    public void mousePressed(MouseEvent e){}

    @Override
    public void mouseReleased(MouseEvent e){}
}

有关其工作原理的详情，请参阅"How to write a Mouse Listener"

检查鼠标光标是否在组件上

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