Designing applications for touch UI
Both touch screens and hybrid devices are supported by Symbian platform. Touch screen enables direct manipulation of content and objects, allowing for far more natural interaction with the device. This means a completely different user experience and interaction style compared to using a hardware keypad.
All applications must be touch-enabled, which means that they can be used with the touch screen alone, regardless of the presence of a keypad. In Symbian platform-based touch devices, the important hardware keys are Send, End, Multi-tasking and Power key.
The application features must follow the platform support for different hardware. When designing a touch-enabled Symbian application, the UI must be designed so that everything can be accomplished by using the touch screen interface, as the potential target devices may or may not have a hardware keyboard.
The touch UI in the Symbian platform is based on the use of resistive and capacitive touch screens. In resistive touch screen technology, two conductive and resistive layers are separated by a thin space. When an object touches this kind of touch panel, the layers are connected at a certain point, and a touch event is registered. This allows efficient stylus control, in addition to finger touch - unlike capacitive panels, which usually register only finger touch. Additionally, resistive touch screen offers a higher resolution and more durability. In capacitive touch screen technology, the panel consists of an insulator such as glass, coated with a transparent conductor (such as indium tin oxide (ITO)). When an object touches the surface of the screen, it results in a distortion of the local electrostatic field, measurable as a change in capacitance. Then a touch controller measures the frequency variations to ascertain the co-ordinates of the object's touch. Capacitive touch screen supports multi-touch.
The hardware is supported by various:
touch-specific components (see Touch support for common UI components)
component and UI behavior changes
layout changes, and
additions to the interaction style.
The touch UI is designed to enable full task flow with touch, with minimal need to switch to hardware keys. Thus, the design ensures that users can complete a task with the chosen interaction method from start to finish.
While designing and implementing applications for touch screen devices based on the Symbian platform, consider interactions that benefit the most from the touch UI.
If you can apply direct manipulation of the UI, for example when moving items from one place to another, or scrolling a page, do not confine the user with unnecessary scrollbars or have the user resort to options list commands.
Instead, enable the user to view pages larger than a screen by panning them directly, and dragging and dropping items rather than marking them and using menu options.
Remember that the most intuitive touch screen interactions that can be performed using a finger are tapping, stroking up/down/left/right, and the long tap.
Utilize strokes that are easily discovered to the users in the given context. It should be explicit to the user where strokes can be performed.
Design to ensure that users can complete a task with the same interaction method from start to finish - touch or hardware keys, stylus, or finger, and using one hand or both hands.
Aim to optimize system performance and battery consumption to provide a fluid and reliable touch user experience.
See Also: