eXtropia: the open web technology company
Technology | Support | Tutorials | Development | About Us | Users | Contact Us
Resources
 ::   Tutorials
 ::   Presentations
Perl & CGI tutorials
 ::   Intro to Perl/CGI and HTML Forms
 ::   Intro to Windows Perl
 ::   Intro to Perl 5
 ::   Intro to Perl
 ::   Intro to Perl Taint mode
 ::   Sherlock Holmes and the Case of the Broken CGI Script
 ::   Writing COM Components in Perl

Java tutorials
 ::   Intro to Java
 ::   Cross Browser Java

Misc technical tutorials
 ::   Intro to The Web Application Development Environment
 ::   Introduction to XML
 ::   Intro to Web Design
 ::   Intro to Web Security
 ::   Databases for Web Developers
 ::   UNIX for Web Developers
 ::   Intro to Adobe Photoshop
 ::   Web Programming 101
 ::   Introduction to Microsoft DNA

Misc non-technical tutorials
 ::   Misc Technopreneurship Docs
 ::   What is a Webmaster?
 ::   What is the open source business model?
 ::   Technical writing
 ::   Small and mid-sized businesses on the Web

Offsite tutorials
 ::   ISAPI Perl Primer
 ::   Serving up web server basics
 ::   Introduction to Java (Parts 1 and 2) in Slovak

 

Introduction to Web Programming
How Events Originate  
  • However regardless of which event handling methodology you use, the origin of events is still the same

  • When a user presses and releases the mouse button over a widget like a button, the windowing system of the computer is notified that the mouse button was pressed and released.

  • The windowing system determines which window the mouse was pressed over. If it is your program's window, it sends the mouse event to your program. However, the windowing system only knows about top level windows. It does not know anything about java controls, dialogs, or buttons. Thus the windowing system notifies your program and lets your program handle things from there.

  • It's then your program's job to determine what components are notified of the event.

  • If the mouse is pressed and released over an OK button for example, the program sends mouse-down and mouse-up events to the OK button object. The button looks at these events and determines if it should generate its own event in response. Thus, if the user clicked on the "clickable" area, the button, the button will generate its own "action event" which is the event that you want to handle to perform an action when the OK button is pressed.
Previous Page | Next Page