In my recent blogs I have been discussing the challenges that developers face building cross-platform applications for Smartphones. The biggest of these is the huge divergence among Smartphone manufacturers which makes cross-platform development almost impossible. As a result, developers resort to creating different code streams for each smart phone platform and continuously port features between them.

I was recently discussing this topic with a colleague when he made the following poignant observation: "While all these Smartphones are diverging on their OS and hardware platforms, they are all converging on the Web Browser rendering engine - WebKit". This statement is so true considering how the iPhone, Android, Palm WebOS, and Symbian have all adopted WebKit as the core rendering engine in their embedded browsers. It also seems that BlackBerrys will also come into the fold after RIM's recent acquisition of TorchMobile. The industry consensus is that this acquisition was mainly to acquire the TorchMobile web browser and port it to the BlackBerry. With this browser convergence, developers should be able to create a single code stream for a web based application (that uses standards based technologies such as HTML, CSS, JavaScript & SVG) and have it render and behave the same across all the Smartphone platforms mentioned above. Of course there are other challenges that need to dealt with such as the differing screen sizes, or the use of native phone functionality such as GPS location and accelerometers.

For the screen size issue there seems to be a general convergence towards 320x480 so developing an application that fits well within these boundaries should work well on most platforms. Worst case, the UI layout would need to be separated based on the phone hardware and the mobile application built to detect this and show the appropriate layout (much like how current web sites show different content based on the PC browser being used).

To use native phone capabilities, there will need to be custom libraries developed to invoke these functions from JavaScript. This is in fact how frameworks such as PhoneGap have solved this problem. Unfortunately this reverts back to the original problem of having to maintain different code bases for each platform. However it is not as bad since the fork in code stream is in specific functional libraries while the core application code base remains common across all platforms. Worst case, the initial versions of the application can be designed to not utilize any hardware specific features (e.g. accelerometers) in order to avoid this issue. As the application matures and gains adoption these features can be added in incrementally where they make sense and add value.

In summary, WebKit may be the solution developers are looking for in order to quickly create and deploy their applications simultaneously on many of the emerging smart phones. Of course this also assumes that the developer has studied their target market and determined that it is absolutely the high end smart phone user and that these users span the multiple platforms. If not it is still much more beneficial to focus on the platform most used by your target user demographic.