Off-line Access to iPhone WebApps in iPhone OS 3.0

Posted by Mattias Sandström on July 8, 2009

iPhone OS 3.0 contains a couple of new features that makes it possible to create off-line capable WebApps directly accessible from the home screen. These techniques are HTML5, JavaScript Database Support, Offline Manifest and support for full-screen HTML-based applications (running without the Safari interface). With these components Tangix is now creating a iPhone interface to statistics in the VirtualTester that will be used as a test-bench of these technologies before launching a broad WebApp.

Using Dashcode to create the UI and adding support for AJAX, graphing and database storage, we have now a fully working prototype of the VT CertStats WebApp. When added to the Home Page, the WebApp behaves as a normal iPhone application but is not distributed through the AppStore, making this ideal in certain environments. With the Offline Manifest, the WebApp will download all needed files from the Internet to have access to the resources when off-line. The Japavscript Database provides a SQL database that is also accessible off-line. These two techniques enables a programmer to create fully off-line applications!

The Dashcode framework contains all UI components that users are seeing in all other programs; lists, pickers and the familiar buttons. The framework is very similar to Cocoa Touch in certain aspects and my knowledge of Cocoa Touch (albeit very basic) greatly helped in understanding how to use the Dashcode framework. The Stack View contain functions such as animations (even cube and flip styles!) and automatic navigation with the back-button.

The only problem is the asynchronous way the Javascript Database operates in. This is a RPIA and turning your code efficiently into pasta-style making it extremely hard to follow. I’d like to have a pint with the designers of this Database API and share their views of how programming should be done....

-- Mattias