Re: dynamic tool tip text

From:

Jim Janney <jjanney@shell.xmission.com>

Newsgroups:

comp.lang.java.programmer

Date:

Thu, 18 Mar 2010 13:11:43 -0600

Message-ID:

<2ppr31zbps.fsf@shell.xmission.com>

Knute Johnson <nospam@rabbitbrush.frazmtn.com> writes:

From: Knute Johnson <nospam@rabbitbrush.frazmtn.com>
Subject: Re: dynamic tool tip text
Newsgroups: comp.lang.java.programmer
Date: Thu, 18 Mar 2010 10:16:51 -0700
Organization: NewsDemon

On 3/18/2010 9:32 AM, Jim Janney wrote:

Thanks. That still doesn't work with a JComboBox, but that turns out
to be because nothing works with JComboBoxes, as is copiously
described in bug ID 4144505, where Sun says "yes we know, but we're
not going to fix it."

Sure it does.

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class test extends JPanel {
    String[] items = {"One","Two","Three","Four","Five"};

    public test() {
        super(new GridBagLayout());

        setPreferredSize(new Dimension(400,300));

        JComboBox b = new JComboBox(items);
        b.addMouseListener(new MouseAdapter() {
            public void mouseEntered(MouseEvent me) {
                JComponent c = (JComponent)me.getSource();
                if (me.isAltDown())
                    c.setToolTipText("ALT is pressed");
                else
                    c.setToolTipText("ALT isn't pressed!");

            }
        });
        add(b);
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                JFrame f = new JFrame();
                f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                test t = new test();
                f.add(t);
                f.pack();
                f.setVisible(true);
            }
        });
    }
}

More precisely, it works on the editor but not on the button.

To be somewhat less unfair to Sun, I did find some discussion of this at

http://java.sun.com/docs/books/tutorial/uiswing/components/combobox.html#listeners

Although JComboBox inherits methods to register listeners for
low-level events -- focus, key, and mouse events, for example -- we
recommend that you don't listen for low-level events on a combo
box. Here's why: A combo box is a compound component -- it is
comprised of two or more other components. The combo box itself
fires high-level events such as action events. Its subcomponents
fire low-level events such as mouse, key, and focus events. The
low-level events and the subcomponent that fires them are
look-and-feel-dependent. To avoid writing look-and-feel-dependent
code, you should listen only for high-level events on a compound
component such as a combo box. For information about events,
including a discussion about high- and low-level events, refer to
Writing Event Listeners.

--
Jim Janney