How to make JSplitPane auto expand on mouse hover?

Question

I want to make a Java program with Swing layout where there is a menu on the left that is expanded when a mouse hovers over the menu area, but auto contracts after your mouse leaves.

I am trying to imitate the effect of something like mobile Youtube for Android, or Weebly's editor. Fro those who don't know, both layouts have menus on the left that expand when your mouse hovers over them. Then after your mouse leaves the area, the menu contracts again and is out of view.

I was able to create the JSplitPane containing my menu successfully, but I have no idea how to make it automatically expand when the user's mouse hovers over the JSplitPane component, or how to make it contract after the mouse leaves the area.

In case anyone is wondering why: This type of menu is easy for the user to use but because it hides away when unneeded, allows me to have more space for the main part of the program.

Any help would be appreciated thanks!

Answer 1

Well make use of jSplitPan.setDividerLocation(location);: Sets the location of the divider. location - an int specifying a UI-specific value (typically a pixel count).

jSplitPane1.addMouseMotionListener(new MouseMotionAdapter() {
            public void mouseMoved(MouseEvent evt) {
                // use evt.getSource() if needed
                jSplitPan1.setDividerLocation(location);
            }
        });

You will probably need to compute the divider location a little bit intelligently. hints: by computing the relevant preferred-size hints. The part relevant should be discovered by you.

Take a look into official tutorial page to know: How to use MouseMotionListeners including other event listeners.