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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-68B999C2-0993-4804-9624-42C3D88BE5C7" xml:lang="en"><title>View |
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13 architecture</title><prolog><metadata><keywords/></metadata></prolog><conbody> |
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14 <p>The following image illustrates the components of the view architecture |
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15 approach.</p> |
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16 <fig id="GUID-A4D968BE-B048-424C-94B5-FAAA7B14C5D5"><title>View architecture classes</title><image href="GUID-2B50C6B1-E1E8-44E6-840B-7FAA206E6C26_d0e47820_href.png"/></fig> |
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17 <p>Symbian platform applications that follow the view architecture require:</p> |
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18 <ul> |
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19 <li><p>a <xref href="GUID-FD2CDEB8-0784-4BE5-A775-170F57D71BBC.dita">UI |
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20 controller</xref> derived from <xref href="GUID-2DBA2DA9-3DA7-381C-842C-9F6FEEDF973E.dita"><apiname>CAknViewAppUi</apiname></xref></p></li> |
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21 <li><p>a <xref href="GUID-DAC32BB9-C0EB-42FF-A596-C2F1A90A4BD7.dita">view |
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22 controller</xref> derived from <xref href="GUID-11967EBB-7439-3775-B287-7560ECA0AF1F.dita"><apiname>CAknView</apiname></xref></p></li> |
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23 <li><p>a <xref href="GUID-DAC32BB9-C0EB-42FF-A596-C2F1A90A4BD7.dita">view</xref> or |
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24 views derived from <xref href="GUID-B06F99BD-F032-3B87-AB26-5DD6EBE8C160.dita"><apiname>CCoeControl</apiname></xref></p></li> |
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25 </ul> |
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26 <p>The view architecture only allows one view to be active in each application. |
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27 If a new view is switched to within an application, the current view is immediately |
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28 deactivated, so this architectural approach is <i>not</i> appropriate in the |
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29 following cases:</p> |
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30 <ul> |
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31 <li><p>Applications with any view that cannot cleanly handle unexpected |
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32 activation of another view in that application.</p></li> |
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33 <li><p>Applications that provide views that can be nested over other |
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34 applications, except where embedding is used.</p></li> |
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35 <li><p>Applications that provide controls that can be used inside |
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36 other applications (for example, using a Web control inside an e-mail viewer |
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37 to show an e‑mail with HTML content).</p></li> |
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38 </ul> |
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39 <p>Typical responsibilities in this architecture are:</p> |
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40 <ul> |
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41 <li><p><parmname>CAknViewAppUi</parmname>-derived class acts as |
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42 a <xref href="GUID-FD2CDEB8-0784-4BE5-A775-170F57D71BBC.dita">UI controller</xref>:</p> |
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43 <itemgroup> |
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44 <ul> |
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45 <li><p>It creates one or more <parmname>CAknView</parmname>-derived |
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46 view controllers.</p></li> |
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47 <li><p>It handles <xref href="GUID-EF7FF39E-929F-4767-B475-5D582D37BB32.dita">events</xref> that |
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48 are not handled by the view controllers.</p></li> |
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49 <li><p>To switch between views, it activates and deactivates views.</p> |
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50 </li> |
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51 <li><p>It handles menu <xref href="GUID-4941C035-C359-4968-9BD5-31F44EE5F810.dita">commands</xref> passed |
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52 to it by the view controllers.</p></li> |
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53 <li><p>It receives events such as <xref href="GUID-DD15F24B-0786-4531-A6C5-A5E70EBE2732.dita">layout</xref> and <xref href="GUID-3B441CDC-AB7A-4D8D-A595-57C21E1D426C.dita">foreground</xref> notifications |
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54 from the run-time environment.</p></li> |
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55 </ul> |
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56 </itemgroup> |
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57 </li> |
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58 <li><p><xref href="GUID-11967EBB-7439-3775-B287-7560ECA0AF1F.dita"><apiname>CAknView</apiname></xref>-derived class acts as a <xref href="GUID-FD2CDEB8-0784-4BE5-A775-170F57D71BBC.dita">view controller</xref></p> |
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59 <itemgroup> |
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60 <ul> |
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61 <li><p>It creates one of more <xref href="GUID-B06F99BD-F032-3B87-AB26-5DD6EBE8C160.dita"><apiname>CCoeControl</apiname></xref>-derived |
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62 views.</p></li> |
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63 <li><p>It handles registering controls for <xref href="GUID-E402616A-7ED8-45AC-B836-99C3A3760B33.dita">key |
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64 event handling</xref>.</p></li> |
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65 <li><p>It handles menu <xref href="GUID-4941C035-C359-4968-9BD5-31F44EE5F810.dita">commands</xref>.</p> |
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66 </li> |
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67 </ul> |
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68 </itemgroup> |
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69 </li> |
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70 <li><p><xref href="GUID-B06F99BD-F032-3B87-AB26-5DD6EBE8C160.dita"><apiname>CCoeControl</apiname></xref>-derived view:</p> |
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71 <itemgroup> |
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72 <ul> |
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73 <li><p>Shows application data and state on the screen.</p></li> |
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74 </ul> |
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75 </itemgroup> |
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76 </li> |
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77 </ul> |
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78 <p>For information on the <xref href="GUID-4F825D83-47A4-36C9-9A25-943A6D799F84.dita"><apiname>CAknApplication</apiname></xref> and <xref href="GUID-935C59EE-AD66-33FE-987B-BD97F5147CC1.dita"><apiname>CAknDocument</apiname></xref>-derived |
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79 classes, see <xref href="GUID-BDDDF68F-F7C3-43AF-8B6C-C77C701FD2A9.dita">Framework |
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80 requirements for GUI applications</xref>.</p> |
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81 </conbody></concept> |