Time for action - play with the feed reader application
Go to the qooxdoo demo feed reader URL (http://demo.qooxdoo.org/current/feedreader/), play with the feed reader application, and feel the qooxdoo application. Perform all the operations available in the application; observe the AJAX behavior, desktop-like features, and so on. Compare the behavior of this application with any typical web application. You can perform the following operations:
Adding a feed to the feed reader
Click on the Add Feed menu in the toolbar and add any feed that you want to put into the feed reader. Let's add the feed to the Google Open Source Blog. Enter Google Open Source Blog in the Title field and http://feeds.feedburner.com/GoogleOpenSourceBlog in the URL field. Click on the Add button. This will add a feed to the User Feeds section:
Checking the feeds
Clicking on the RSS feed nodes on the tree panel will load the feeds on the right-hand side panel. Once you click on a particular feed post on the top pane in the right-hand side panel, it will load the details of that particular feed post on the bottom of the right-hand side panel. Go to User Feeds | Google Open Source Blog and check the Google Open Source Blog feed.
If you observe closely, it just loads the required data on the respective content area without disturbing user context or without reloading the entire page (as shown in the following screenshot). This is done through AJAX. In AJAX applications, the application just sends and receives the required data and updates only the impacted portion in the GUI. This helps to retain the user context, improves performance because of less transfer of data between client and server, and improves the usability of the GUI:
Try the following actions, too:
- Reload
- Preferences
- Remove feed
What just happened?
You played with a Rich Internet Application (RIA) developed in qooxdoo. Let's have a look at the key aspects provided by an RIA developed in qooxdoo.
AJAX-based RIA does not reload the whole page every time; instead it just loads the required data in the respective content area. This is the main differentiating aspect in RIA. It holds the user context all the time, thus the user experience is very much appreciated by the users. RIA applications do not open multiple browser windows, as it is done in the traditional web application using window.open(). Instead, it uses the modal dialog and avoids the floating browser windows. RIA applications do not wipe out the whole page and reload the new page, as it is done in traditional web applications; instead, they retain the user context, send and receive only the necessary data, and update only the changed or impacted portion of the screen. qooxdoo is an RIA framework based on AJAX.
RIA provides rich features developed through the off-the-shelf widgets provided by RIA frameworks such as qooxdoo. Because of this, RIA provides rich user experience. You have seen the toolbar, split-pane, modal dialog, and so on in the feed reader application. There are many more widgets provided by qooxdoo for various purposes that you'll come to know about in the coming chapters.
qooxdoo provides a wide range of widgets in the GUI library, which helps you to develop your application pretty quickly with all the rich features. For example, qooxdoo provides the Tree widget that does not come with the plain HTML, it supports column sorting on the table and the remote data model for the table. There are many more widgets with very nice features that are readily available for you. You don't have to spend time to develop these things on your own in HTML and struggle between multiple browser implementations. Instead, just focus on your application's functionalities.