1 <?xml version="1.0" encoding="utf-8"?> |
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2 <!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. --> |
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3 <!-- This component and the accompanying materials are made available under the terms of the License |
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4 "Eclipse Public License v1.0" which accompanies this distribution, |
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5 and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". --> |
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6 <!-- Initial Contributors: |
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7 Nokia Corporation - initial contribution. |
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8 Contributors: |
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9 --> |
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10 <!DOCTYPE concept |
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11 PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd"> |
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12 <concept id="GUID-ACC71D0D-32C4-5DAF-B4D9-66013A073FD4-GENID-1-8-1-6-1-1-4-1-8-1-4-1-8-1" xml:lang="en"><title>Synchronising |
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13 FEP Instantiations</title><shortdesc>This topic describes how to synchronize settings across different |
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14 instances of the same FEP.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody> |
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15 <p>As mentioned previously, the FEP architecture has been designed so that |
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16 each running application has its own instance of the current FEP. <codeph>CCoeFep</codeph> provides |
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17 support for synchronizing attributes across all of these instances, so that |
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18 when one instance changes the value of an attribute, the others are automatically |
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19 updated. In order for this to happen, the FEP has to do several things. </p> |
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20 <ul> |
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21 <li id="GUID-EC8E4D77-BE0E-5A5E-87B0-817109AD5D44-GENID-1-8-1-6-1-1-4-1-8-1-4-1-8-1-3-2-1"><p>Override the four pure |
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22 virtual functions that <xref href="GUID-ADAA039A-7BF3-3B06-8486-2E3604C2633D.dita"><apiname>CCoeFep</apiname></xref> inherits from <xref href="GUID-B0007B23-6745-31BE-A832-9ACA4C12E3E6.dita"><apiname>MFepAttributeStore</apiname></xref>: <codeph>NumberOfAttributes()</codeph>, <codeph>AttributeAtIndex()</codeph>, <codeph>WriteAttributeDataToStreamL()</codeph> and <codeph>ReadAttributeDataFromStreamL()</codeph>. <codeph>NumberOfAttributes()</codeph> should return the number of attributes that are to be synchronized across |
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23 all instances of the FEP, <codeph>AttributeAtIndex()</codeph> should return |
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24 the UID of the specified attribute, and <codeph>WriteAttributeDataToStreamL()</codeph> and <codeph>ReadAttributeDataFromStreamL()</codeph> should |
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25 write/read the specified attribute’s data to/from the provided stream. </p> </li> |
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26 <li id="GUID-0163FF77-8495-5812-AF0D-2FB9AB376EC5-GENID-1-8-1-6-1-1-4-1-8-1-4-1-8-1-3-2-2"><p>When the object of the <xref href="GUID-ADAA039A-7BF3-3B06-8486-2E3604C2633D.dita"><apiname>CCoeFep</apiname></xref> -derived |
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27 class has been fully constructed, call <codeph>CCoeFep::ReadAllAttributesL()</codeph>. |
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28 This calls the <codeph>ReadAttributeDataFromStreamL()</codeph> virtual function |
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29 for each of the UIDs that the FEP requires to be synchronized (as specified |
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30 by <codeph>NumberOfAttributes()</codeph> and <codeph>AttributeAtIndex()</codeph>). </p> </li> |
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31 <li id="GUID-E4435F88-8C8F-5E93-8587-101DBCA7FA03-GENID-1-8-1-6-1-1-4-1-8-1-4-1-8-1-3-2-3"><p>After internally changing |
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32 the value of an attribute that is to be synchronized, call <codeph>CCoeFep::WriteAttributeDataAndBroadcastL()</codeph> to |
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33 propagate that change to all the other instances of the FEP. The parameter |
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34 identifies the attributes that are to be synchronized, using UIDs. See the |
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35 Symbian website for information on how to be allocated UIDs. </p> </li> |
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36 </ul> |
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37 <p>The purpose of the <codeph>SynchronouslyExecuteSettingsDialogL()</codeph> exported |
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38 function, which the FEP must provide, is to launch a dialog that allows the |
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39 user to change any settings specific to that FEP. As mentioned above, there |
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40 is no guarantee that any instance of that particular FEP exists when this |
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41 function is called. In order for the dialog launched by <codeph>SynchronouslyExecuteSettingsDialogL()</codeph> to |
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42 be able to edit settings that are required to be synchronized across all running |
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43 applications, the dialog class must derive from <xref href="GUID-270424BB-124B-39FF-9CDA-5CAFB5407FAE.dita"><apiname>MFepAttributeStorer</apiname></xref>. |
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44 The dialog class’ implementation of <xref href="GUID-270424BB-124B-39FF-9CDA-5CAFB5407FAE.dita"><apiname>MFepAttributeStorer</apiname></xref> ’s |
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45 virtual functions should be the same as the <xref href="GUID-ADAA039A-7BF3-3B06-8486-2E3604C2633D.dita"><apiname>CCoeFep</apiname></xref> -derived |
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46 class’ implementation of them. For an example of this, see TFEP1Plugin. When |
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47 the dialog is launched it needs to call <codeph>MFepAttributeStorer::ReadAllAttributesL()</codeph> to |
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48 correctly initialize all the settings. Conversely, the settings in the dialog |
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49 are committed by calling <codeph>MFepAttributeStorer::WriteAttributeDataAndBroadcastL()</codeph>. </p> |
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50 </conbody></concept> |
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