Touch-enabled -vs. touch-optimized

Rather than being -touch-enabled, certain applications can be touch-optimized, that is, designed -primarily for touch screen interaction. When developing applications for a -touch interface, it is important to consider interactions which benefit the -most from touch UI. While physical strokes and gestures allow for more natural -interaction with objects, the fact that one can apply them does not mean they -are appropriate for every situation.

Following are some useful tips -that can be used when designing applications for touch use:

It is imperative that design decisions are based on real-time touch -use cases.
Since touch functions require a fair amount of discovery from the user, -it is good if only very obvious functions are made touch-enabled.

Why to use touch

More flexible: Compared to fixed hardware keys, the interface -can change dynamically. This allows for more flexible configurations depending -on the functionality requirements, languages, and so on. Thus a very small -screen can change its buttons as required. Also, with indirect strokes and -gestures, there are numerous possibilities of flexibility. No use of physical -buttons is required.
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More intuitive: Manipulating objects directly by touching them -is natural and intuitive. Keyboards, mice, trackballs, and other input devices -are not able to convey as much subtlety as touch can. Direct manipulation -can deliver a lot more meaning to controlling a tool.
More fun: One can design a game in which users press a button -and an on-screen avatar swings a tennis racket. But it can be simply more -entertaining to mimic movements physically, and to see the action mirrored -on-screen. Strokes and gestures encourage play and exploration of a system -by providing a more hands-on experience.
More engaging: Through play, users start to engage with the -interface, first by trying it out to see how it works.

Limitations of touch

Heavy data input: A hardware keyboard is faster for most people -to use when entering a large amount of text or numbers, and applications which -involve heavy data input are not necessarily ideal for touch devices. Virtual -keyboards are adequate, for example, for messaging applications. Consider -utilizing adaptive methods - such as options and selections filtered according -to what is available on the screen or in a list - and pre-filled items, when -possible.
Reliance on the visual: While the Symbian platform provides -tactile feedback capability, some applications can rely heavily on visual -feedback to indicate actions. Allow for scalability, larger buttons and text -sizes, for example, for visually impaired users.
Reliance on the physical: Touch interface can be more demanding -on the physical context than mechanical keys. Tapping a touch screen button -can be difficult while wearing winter gloves, or with long fingernails. The -inverse is also true: the more subtle and small the movement, the less likely -it is that everyone will be able to do it. To overcome this, the most basic -use cases, such as answering an incoming phone call, must utilize large enough -elements and straightforward interaction.