1. Know your customer first: The first aspect of any UI is in terms of who is using it and for what purpose. This is critical in terms of adding the value add ons to the UI. Normally, a lot of back end research goes to zero down on users and usages. The UI then has to be customized for the particular user profile. For example: Gaming and Music can be supported on the same software versions (e.g S 60 for Nokia), but the UI has to be customized for a gaming freak versus a music listener.
2. Top Down in design: The UI design and development should begin from the fully loaded version instead of the base version. The functions and apps should be in a modular format, which can be removed from the fully loaded version to lighten it up for lower versions.
Examples of Modular formats: SMS + voice module, FM + MP3 Module, MP4 + Video Player module, Music Module(supports all music formats), Gaming Module, Navigation Module, Internet Browsing, RSS feeds module, Calendars and Organiser module, other apps.
This is also important from device memory and selection of relevant hardware and chipsets perspective.
3. The case for shortcuts–> Content/Context Specificity: If the device is for a particular use, then there should be hotkeys or shortcut keys on the panels or the UI to enable a one click access to the function. Normally phones have one key access to music, camera, internet etc. This establishes and supports the USP by customizing your UI around specific content/context.
4. Screen View: A judicious use of the small screen size is a high priority. Craming it up with too much information could reduce readability. (I have never managed to read those “X” line “how to” menus that keep popping up on the screen). In devices that need to support RSS feeds, it is important to balance the view in terms of visibility/readibility versus blocking out everything else in the background.
5.Scroll Conservation:It is essential that the main menu and the subsequent ones be customized so that the content viewing doesnot require a scroll down! Many users find the act of scrolling down on a menu view to be irritating. It also means that the menu is not sure what they are looking for in the first place and is not able to provide the required info in one screen.
6. Click Conservation: Similarly, the act of many clicks into menus, sub menus, prompts, functions and sub functions etc is avoidable. A few UIs require 6 or more (even 10 in exterem cases) clicks for the user to access a particular point in the system. You are clearly telling the user to sort your mess by navigation his way into your UI. There is no intutiveness and short route to the functions he so desires. It also shows that you dont know what your user is using your device for. A S 60 UI navigation path is 900 rows in lenght and some of these paths are 6 – 10 clicks long. The 900 statistic shows a diffuse focus in terms of device –> customer integration and the 6-10 click path shows UI inability to intuitively map its usage.
7. Intuitive Design: The intuitiveness of design is probably culture/ language/ region dependent. However there is a strong case of integrating user requirements with the UI and hardware of the device. (e.g: After a call to a new number, imagine one click “Save” option to “add to contacts”. On the other hand, imagine the path Options–> save as –> add to contacts. That is “one click” too many).
8. Energy Saving Options: Screens such as QVGA and TFT can be harsh on power. A UI should be able to switch off / stand by to save on power drainage when not in use for “x” minutes. Similarly, it should be able to close the apps which are open and are not being used in favour of conserving battery life.
9. Touch: A touch based UI needs to allow room for the “touch”. (That in fact necessitates 3 inch screens to accomodate for the fingers). The idea is not to cramp the screen with multitude of options and less space making the touch experience a very tedious one.
These are a few generic principles to be kept in mind in UI designing for Handheld devices and mobiles. The ultimate objective is to make the browsing and navigation experience on the device to be a “Wow”.