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Not long ago it was easy for user interface (UI) designers – the UI of an application had to be designed for just one device: a standard PC screen. The resolution was at least 800 x 600 pixel, if not higher.  The input devices were always the same: Keyboard and mouse.  This blog post will not deal with the technical aspects of UI development. I will also bypass the issue of different JavaScript or DHTML for different browsers. I will only focus on the usability of the UI.  With the rise of the mobile age, the design of UIs have become a lot more difficult: There is no standardised device available anymore. One can take a pick from the multitude that’s on offer- Subnotebooks, PDAs, Smartphones, Tablet-PCs and now the new Ultra-PCs. Each device category comes with different screen resolutions, different colour definitions and different approaches to entering information. The standard keyboard and mouse belong in the past. Today’s mode is Blackberry-like navigation and touch-screens. Each device has a variety of special function keys. Some come with a keyboard, some come without. In this world, therefore, a standardised UI is not just unavailable, it is not viable. Each UI needs be designed specific to the target device.   An important consideration is to support the standard features of the target device. A good example is the Blackberry: With the great concept of the scroll wheel, navigation is easy and fast. Here it becomes an absolute necessity to support this efficiency, if you want your Blackberry user to be satisfied with the application.   Another example are devices with touch-screen and without keyboard. Here we need a different approach, from that to the Blackberry. Instead of the Blackberry-style menu we need a more classical UI. The entry of long text should be avoided. If it can’t be, auto-completion or text templates should be offered.   Stay focused on the most important aspect of any interaction- the user. The look of the UI changes with the profile of the end-user. To elucidate this difference, let us compare two separate individuals and their requirements. While a sales representative will find it easy to get used to a Windows Mobile device and the new mobile CRM application, it would be a tall order to convince a service technician that the handy PDA is going to make life any easier. Applications for the blue-collared have to be designed so as to easily fulfil the task at hand. One important rule here: Big screen elements! So even if the user loses his stylus, he should still be able to use the application. Therefore, IMO it is a must that the user can click buttons and links with his fingers. Small screen elements can be quite a bad idea! Here are some more guidelines that should apply to all mobile applications:


  • Reduce the functionality: Less is more (fast, that is). Standard SAP mobile applications like MAM are great. They offer maximum functionality. Every customer will find the required business case. But when considering a small mobile device, packing it with the application as it is, complete with even irrelevant functions, serves no purpose. Remove all functionality that is unnecessary (easily achieved with the mCAF enhancement concept).

  • Reduce the amount of clicks: Every company works differently and has different workflows. Therefore, the UI screenflow should support the natural way the user works.

  • The “right” content: This is maybe the most difficult topic. On the one hand you want to have as much information,  on one screen, as possible to avoid unnecessary screen changes (which demands its own share of clicks and time). But on the other hand, huge amounts of data require scrolling and the screens need longer to load. There is no general solution for this problem. This has to be decided case by case. If your user is not satisfied with the application then try to split a screen in two or combine two screens into one.

I haven’t discussed the technical details of the UI design in this post. This is a complete topic in itself. I just wanted you to understand that mobile applications will only be successful if they are easy to use. And the key to this usability is an optimally designed user interface.  But enough for today, let’s get the Business in Motion!.

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  1. Norbert K├Âlbl
    Hi Alex,

    nice article! I completely agree with your key conclusions about the architecture and design of mobile applications. We also tried to consider those aspects when we custom-developed a mobile application based on some standard processes of SAP’s MAM ( /

    I have never heard of the “mCAF enhancement concept” before, where can I find more information about it?

    Best regards,


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