--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Symbian3/SDK/Source/GUID-BA0D9DA9-3B54-4964-A4D6-9ADA4DEB7231.dita	Wed Mar 31 11:11:55 2010 +0100
@@ -0,0 +1,90 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->
+<!-- This component and the accompanying materials are made available under the terms of the License 
+"Eclipse Public License v1.0" which accompanies this distribution, 
+and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". -->
+<!-- Initial Contributors:
+    Nokia Corporation - initial contribution.
+Contributors: 
+-->
+<!DOCTYPE task
+  PUBLIC "-//OASIS//DTD DITA Task//EN" "task.dtd">
+<task id="GUID-BA0D9DA9-3B54-4964-A4D6-9ADA4DEB7231" xml:lang="en"><title>Receiving
+Data from Sensors</title><shortdesc>You can implement a data listener to receive data from the sensors.
+Based on the data received, you can perform specific actions on the Symbian
+device. For example, if you receive information from the sensor about the
+distance between the device and the user then based on this information, you
+can disable or enable the loudspeaker mode on the Symbian device.</shortdesc><prolog><metadata><keywords/></metadata></prolog><taskbody>
+<prereq id="GUID-E09C6ABC-F717-4791-A2EE-491421D2BD30">       <p>Before listening
+for sensor channel data, you must <xref href="GUID-4B709839-8EEF-4AD2-9868-9AF0176B1E5B.dita#GUID-4B709839-8EEF-4AD2-9868-9AF0176B1E5B/GUID-FBBD3A8B-F240-4DC0-B516-3A51FDD86A88">open
+the sensor channel</xref>.</p>     </prereq>
+<steps id="GUID-4DD07DEC-6017-4237-BE46-1D69E5FBD744-GENID-1-8-1-9-1-1-6-1-4-1-4-1-5-1-3-2">
+<step id="GUID-CE0EE6EE-84A7-46F6-8590-C75FAA381843"><cmd>Implement the data
+listener.</cmd>
+<info><p>Inherit from the <parmname>MSensrvDataListener</parmname> interface
+and implement the following pure virtual functions: <xref href="GUID-519E744E-246C-3F4A-A869-F25B03F1126F.dita#GUID-519E744E-246C-3F4A-A869-F25B03F1126F/GUID-92EDE76E-F5D8-3D45-939B-FD5C03347AE8"><apiname>MSensrvDataListener::DataReceived</apiname></xref>, <xref href="GUID-519E744E-246C-3F4A-A869-F25B03F1126F.dita#GUID-519E744E-246C-3F4A-A869-F25B03F1126F/GUID-F6C22940-A276-38C2-890F-CA45B75D613F"><apiname>MSensrvDataListener::DataError</apiname></xref> and <xref href="GUID-519E744E-246C-3F4A-A869-F25B03F1126F.dita#GUID-519E744E-246C-3F4A-A869-F25B03F1126F/GUID-4062844D-2F25-38FC-B91A-DD5B41E6FF3F"><apiname>MSensrvDataListener::GetDataListenerInterfaceL</apiname></xref></p><codeblock xml:space="preserve">class DataListener:public MSensrvDataListener
+    {
+    public:
+        void DataReceived(CSensrvChannel&amp; aChannel, TInt aCount, TInt aDataLost )
+        {
+        ...
+         //Implementation
+        }
+    void DataError( CSensrvChannel&amp;, TSensrvErrorSeverity)
+        {
+        ...
+         //Implementation
+        }
+    void GetDataListenerInterfaceL( TUid, TAny*&amp;)
+        {
+        ...
+         //Implementation
+        }
+    };</codeblock></info>
+</step>
+<step id="GUID-107B26D8-CD5A-4571-8441-F1A5A2C0EB2B"><cmd>Start data listening.</cmd>
+<info><p>Pass an instance of data listener implementation using the <xref href="GUID-22DC917F-D833-3531-AB2D-A6E2D52EF844.dita#GUID-22DC917F-D833-3531-AB2D-A6E2D52EF844/GUID-F851A108-C72F-3132-BE15-DC41CACB64F9"><apiname>CSensrvChannel::StartDataListeningL()</apiname></xref> function.</p><codeblock xml:space="preserve">//Instance of the data listener implementation
+DataListener dataListener; 
+...
+CSensrvChannel* channel;
+...
+channel-&gt;StartDataListeningL(&amp;dataListener, 1, 1, 0);
+...</codeblock><p> When new data is available to be read in the sensor channel,
+the client is notified by the <xref href="GUID-519E744E-246C-3F4A-A869-F25B03F1126F.dita#GUID-519E744E-246C-3F4A-A869-F25B03F1126F/GUID-7EE31046-31A6-356E-AFEF-2E8C003A7F15"><apiname>MSensrvDataListener::DataReceived(CSensrvChannel
+&amp;,TInt,TInt)</apiname></xref> callback function. The channel data is received
+into the receiving buffer. The receiving buffer is allocated from the heap
+in the client's thread and its size is the channel data item size multiplied
+by the maximum number of data items. </p></info>
+</step>
+<step id="GUID-40F9F566-475E-4ECD-B420-70EB1B77DEAA"><cmd>Read the channel
+data from the receiving buffer using the <xref href="GUID-22DC917F-D833-3531-AB2D-A6E2D52EF844.dita#GUID-22DC917F-D833-3531-AB2D-A6E2D52EF844/GUID-EC1AF564-F05D-3729-B0C9-7573A1F79B86"><apiname>CSensrvChannel::GetData()</apiname></xref> function.
+For more information about handling data notifications, see the following <xref href="GUID-BA0D9DA9-3B54-4964-A4D6-9ADA4DEB7231.dita#GUID-BA0D9DA9-3B54-4964-A4D6-9ADA4DEB7231/5876a529-0484-497d-8cf8-9ceb9c725388">Example</xref>.</cmd>
+</step>
+<step id="GUID-D3928C98-3D10-40BE-A63E-584969AA0416"><cmd>After you get the
+required sensor data feeds from the sensor channel, you can stop data listening
+using the <xref href="GUID-22DC917F-D833-3531-AB2D-A6E2D52EF844.dita#GUID-22DC917F-D833-3531-AB2D-A6E2D52EF844/GUID-0129F5FA-BD26-37F0-8FE4-19F393AA817C"><apiname>CSensrvChannel::StopDataListening()</apiname></xref> function.</cmd>
+<stepxmp><codeblock xml:space="preserve">channel-&gt;StopDataListening();</codeblock></stepxmp>
+</step>
+</steps>
+<example id="5876A529-0484-497D-8CF8-9CEB9C725388"><p>The following example
+shows how to handle the double tapping data notification that is received. </p><p>Check
+the channel type of the received data and then receive the data object using
+the <xref href="GUID-22DC917F-D833-3531-AB2D-A6E2D52EF844.dita#GUID-22DC917F-D833-3531-AB2D-A6E2D52EF844/GUID-EC1AF564-F05D-3729-B0C9-7573A1F79B86"><apiname>CSensrvChannel::GetData()</apiname></xref> function. The <parmname>aCount</parmname> parameter
+provides the details about the number of data objects in the channels receiving
+buffer. This number can be zero if the buffering period is used when data
+listening is started. The <parmname>aDataLost</parmname> parameter provides
+the details about the number of the lost data objects. For example, in heavy
+load situations. </p><codeblock xml:space="preserve">void CTestClass::DataReceived( CSensrvChannel&amp; aChannel, 
+                               TInt aCount, 
+                               TInt aDataLost )
+    {
+    if ( aChannel.GetChannelInfo().iChannelType == KSensrvChannelTypeIdAccelerometerDoubleTappingData )
+        {
+        TSensrvTappingData tappingData;
+        TPckg &lt;TSensrvTappingData&gt; tappingPackage( tappingData );
+        aChannel.GetData( tappingPackage );
+        }
+    }</codeblock></example>
+<postreq id="GUID-69071DC2-EB41-43BA-8DFC-CE2D4423AF8A"><p>End the session
+with the sensor channel using the <xref href="GUID-22DC917F-D833-3531-AB2D-A6E2D52EF844.dita#GUID-22DC917F-D833-3531-AB2D-A6E2D52EF844/GUID-0B8F50A6-2CA1-316A-82AB-AA026005E810"><apiname>CSensrvChannel::CloseChannel()</apiname></xref> function.</p></postreq>
+</taskbody></task>
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