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  PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
<concept id="GUID-1FCD0312-7B28-47F9-BE54-822B74A8934C" xml:lang="en"><title>Designing
applications for touch UI</title><prolog><metadata><keywords/></metadata></prolog><conbody>
<p>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.</p>
<fig id="GUID-0895B1BD-27D2-4824-A02C-F89137A16E53">
<image href="GUID-59F26729-3FFB-48AE-91FB-4B9AC2955A06_d0e74654_href.png" scale="60" placement="inline"/>
</fig>
<p>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. There
are only three mandatory hardware keys in touch devices based
on the Symbian platform - Send, End, and Multi-tasking key.</p>
<p>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.  </p>
<p>The touch UI in the Symbian platform is based on the use of resistive and
capacitive touch screens. In <b>resistive touch screen</b> 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 <b>capacitive touch screen</b> 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 <xref href="GUID-17C64C2F-9426-4B41-9F0A-23060289D644.dita">multi-touch</xref>.</p>
<p>The hardware is supported by various:</p>
<ul>
<li><p>touch-specific components (see <xref href="GUID-BB8B3A11-0BBC-4759-A7F4-A28C9E70573F.dita">Touch
support for common UI components</xref>)</p></li>
<li><p>component and UI behavior changes</p></li>
<li><p>layout changes, and</p></li>
<li><p>additions to the interaction style.</p></li>
</ul>
<p>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. </p>
<p>While designing and implementing applications for touch screen devices
based on the Symbian platform, consider interactions that benefit the most
from the touch UI.  </p>
<p>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.</p>
<p>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. </p>
<ul>
<li><p>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. </p></li>
<li><p>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. </p></li>
<li><p>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. </p></li>
<li><p>Aim to optimize system performance and battery consumption to provide
a fluid and reliable touch user experience. </p></li>
</ul>
<p><b>See Also</b>:</p>
</conbody></concept>