l_combobox.rb - a combobox object for Locana

Author: Michael Davis, mdavis@locana.org

Copyright: (C) 2000, 2001, 2002 Seva Inc. and Seva Software - www.sevasoftware.com

Home page: www.locana.org

License: Same as Ruby

These classes provide a combobox for Locana. A combobox is a Ltextbox with a popup list box (Lcombobox_listbox based on the Llistbox class). You can type in the textbox directly or select an item from the popup listbox.

Status

• It works.

Todo

• None planned

History

• 10/10/2003 - When typing characters does not hit on an item in the listbox, the last character is ignored and the last valid item in the listbox remains visible. Before these enhancements, the textbox would contain only the typed in characters, now it shows the last item that was valid from the listbox.

               When pressing the delete key or backspace key always shows the listbox item that fits with the new string.  The backspace/delete key is ignored when the new text does not hit a value in the combobox.
  

• 7/12/2003 - Modified to draw the combobox directly into the GUI. The popup listbox is now a Llistbox that acts like a popup window. The combobox is now an extension to Ltextbox class with a button to open/close the popup listbox. This really simplified the design.
• 02/10/2002 - Updated to conform to the new event handler design.
• 11/20/2002 - Bug fixes where the :on_exit was not always processed correctly.
• 8/22/2002 - Added support for typing all characters into the combobox. The textbox is filled with the first matching element in the listbox. When a matching element is not found, you will get beeped and the new character is ignored.
• 6/19/2002 - Clicking the button with the listbox already open will now close the listbox.
• 6/6/2002 - Changed the base object of Lobject to Lgroup. This simplified some portions of the combobox.
• 5/31/2002 - Fixed several bugs with some events firing twice or not at all. Fixed bug where clearing out the content of the combobox was not firing an after_update event correctly. Fixed bug where clearing the content and choosing the content could cause an error. The textbox now inherits all it’s attributes from the combobox. Fixed a subtle sizing issue that could cause the combobox to shrink under some circumstances.
• 5/15/2002 - Put the popup listbox into it’s own window so it’s size is not constrained by the parent window.
• 2/24/2002 - Added support for new syntax changes in 0.81. All events now looks like they are coming from the combobox rather than the textbox. Also fixed the :on_enter and :on_exit events (they were getting processed when entering and leaving the listbox).
• 1/30/2002 - First official release.
• 1/27/2002 - Created because Tk did not provide a similar object. I know there are combo boxes that you can add on to tk, but this implementation is a lot simpler that any Tk code I could find on the web.