Mobile IxD

Many people find it challenging to enter data on their mobile device. Some mobile features allow for voice input, but most data entry tasks require manual input.

Data input varies between devices. For those with touch screens, input can be accomplished by using a stylus to either tap the keys of a virtual keyboard or through handwriting recognition. Devices without a touch screen require physically pressing hardware keys – most of which use a 9-key layout where multiple characters are accessible on each key, though the inclusion of a full QWERTY (or similar) keypad has become more popular. Devices with a 9-key layout typically include Nuance's T9® Text Input or other predictive text input software.

In addition to character input, a device has one or more keys, virtual or physical, that help the user control the input, such as inserting a new line or deleting characters. Designers should understand the input methods available to the user and optimize the experience to make full use of those methods.

The most usable method of input on a mobile device is none at all; design the interface to minimize input and to provide selectable items (e.g., a list of cities) rather than requiring input
Pre-fill fields with default values or previously entered data
Change input modes (e.g., from text to numbers, from sentence case to all lower case) automatically based on the data required for the field in focus
Touch-screen input
- Target-size matters - research by Microsoft (similar results found by others) indicates that the minimum target size is 5.04 mm (21x21 pixels) at 24dpi
- Stylus-on-display friction can affect the user’s accuracy when tapping targets, as can left or right-handedness
- Consider whether the platform automatically moves content currently displayed on the screen up to make space for a virtual keyboard is or if the keyboard is overlaid on top of the existing content or whether this behavior can be specified by the product
9-key input
- Default to predictive text rather than multi-tap, especially when long text strings are likely
- Each device and device manufacturer can implement a different version or flavor of T9® Text Input – some allow the user to enter their own words, though differing on the method this is accomplished, and some allow the creators of a product to include or access different databases that may allow context-relevant words, names or other character strings to be more readily available to the user
QWERTY or other full keyboard input
- Do not assume that a full keyboard makes input easier for everyone – for example, consider that these devices are typically wider, making it more difficult for people with smaller hands to use it one-handed and thereby reducing the potential that they have a hand free to perform another activity that your product may require
- Many devices with keyboards also include a predictive text input method, though they differ on whether it is enabled by default or not

dave@mobileixd.com