在Java Swing中创建一个不可见的按钮

Question

I have seen many times on Java Swing GUIs buttons that look like images until the mouse rolls over them. They appear to not have their content area filled. When the mouse rolls over them, the content area fills in but the button looks as though the mouse is not hovering over it. An example of this would be the toolbar of buttons used to activate each demo in SwingSet2.

How is this effect possible?

EDIT: Here are images that illustrate my question:

These are using the Window Look&Feel on Vista. The images were captured from the SwingSet2 demo toolbar.

Thanks!

Answer 1

Here is an easy way to do it. This code will add a resized image to the JButton and remove the button's borders and filled area except when the mouse is on the button.

 public JPanel hooverImages(){
        JPanel panel;
        ImageIcon icon;
        Image img;
        JButton button;
        String name = "image"


        icon = new ImageIcon(getClass().getResource("/gui/resources/"
                + name+".png"));
        img = icon.getImage(); 

        button = new JButton(new ImageIcon(img.getScaledInstance(30, 30
                , Image.SCALE_SMOOTH))); //adds resized image to button.
        button.setBounds(20, 0, 40, 40);
        button.setContentAreaFilled(false); //this is the piece of code you needed
        button.addMouseListener(new MouseAdapter(){
            @Override
            public void mouseEntered(MouseEvent event){
                JButton buton = (JButton)event.getSource();
                buton.setContentAreaFilled(true);  //when hoovered it will show borders and fill area.
            }

            @Override
            public void mouseExited(MouseEvent event){
                JButton buton = (JButton)event.getSource();
                buton.setContentAreaFilled(false); //when mouse is not on button then it will look the same.
            }
        });
        panel.add(button);

     return panel;
}

Answer 2

right click on the jButton, click properties and set Opacity to false. OR add this to your code. JButton.setvisible(false);

Answer 3

It has been a while since I've played with any of that, but I believe it is from JButton's setRolloverIcon inherited from AbstractButton. I believe you have to enable rollover as well.

Answer 4

Update This is what you want. Flat Button

I know it says the Windows L&F, which you can set in SwingSet2, but it doesn't mean SwingSet2 didn't replace some of the underlying UI handlers to gain the effect they needed along with using the Windows L&F.

Original Response

Rough version with no pictures. Change border and colors to suite your needs.

 public static void main(String[] args) {
    JFrame frame = new JFrame("Example");
    frame.setLayout(null);
    frame.setSize(800, 600);
    JButton button = new JButton("Hover Me");
    button.setBackground(Color.LIGHT_GRAY);
    button.setBounds(10, 10, 60, 40);
    button.setBorder(BorderFactory.createEmptyBorder());
    button.addMouseListener(new MouseAdapter() {

        @Override
        public void mouseEntered(MouseEvent e) {
            JButton button = (JButton) e.getComponent();
            button.setBackground(Color.LIGHT_GRAY.brighter());
            button.setBorder(BorderFactory.createBevelBorder(BevelBorder.RAISED));
        }

        @Override
        public void mouseExited(MouseEvent e) {
            JButton button = (JButton) e.getComponent();
            button.setBackground(Color.LIGHT_GRAY);
            button.setBorder(BorderFactory.createEmptyBorder());
        }
    });
    frame.add(button);
    frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
    frame.setVisible(true);
}

Answer 5

If you add any JToggleButton with an icon to a JToolBar it will behave like this. If you don't want it to be in a tool bar, try setBorderPainted(false) . I know it works on a GTK LaF, try it with windows.