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<concept id="GUID-0C19D3F1-CF60-4760-8A77-242E14647738" xml:lang="en"><title>Touch
UI observer interfaces</title><prolog><metadata><keywords/></metadata></prolog><conbody>
<p>To support the touch functionality in existing UI components too, S60 5th
Edition introduced new observer interfaces to the existing components. These
are:</p>
<ul>
<li><p><i>Navigation decorator observer</i></p><p>The navigation decorator
observer interface is used in the navigation pane. The interface receives
an event indicating that the decorator’s right or left arrow has been tapped
(or the navi label), and then the observer implementation can perform an action
(for example, raise the volume or change focus to the next tab). This might
be useful if you implement custom controls to be included in the navigation
control.</p><p>It is defined by <codeph>MAknNaviDecoratorObserver</codeph>.
The observer can be set by <codeph>CAknNavigationDecorator::SetNaviDecoratorObserver</codeph>.</p> </li>
<li><p><i>Long tap detector</i></p><p>The long tap detector (<codeph>CAknLongTapDetector</codeph>)
is an Avkon component that an application or control can use to receive long
tap events.</p><p>The long tap handler must inherit from <codeph>MAknLongTapDetectorCallBack</codeph> and
implement the <codeph>HandleLongTapEventL</codeph> call back function for
long tap events.</p> <p>When the stylus is held down in the same position,
an animation starts in about 0.15 s to show that the long tap functionality
has started. Animation is provided by AVKON and cannot be changed by the application
or control. However, animation can be turned off using the class <codeph>CAknLongTapDetector</codeph> in
the Touch UI utilities API.</p> <p>For implementation infomation, see the <xref href="GUID-92018B6B-3CBB-434D-9E61-F271C67E98E3.dita">Touch UI utilities API specification</xref>.</p></li>
<li><p><i>Double-click support in lists</i></p><p>In order to receive double-click
events from a list or grid, the object that wishes to be informed must implement
and register the <codeph>MEikListBoxObserver</codeph> interface via <codeph>CEikListBox::SetListBoxObserver</codeph>. </p></li>
<li><p><i>Title pane touch observer</i></p><p>The title pane touch observer
enables you to provide functionality for title pane touch events. For implementation
information, see the <xref href="GUID-B876D548-FD40-4369-B328-7427002B4851.dita">Title
pane touch observer API specification</xref>.</p></li>
</ul>
</conbody></concept>