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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-BDDDF68F-F7C3-43AF-8B6C-C77C701FD2A9" xml:lang="en"><title>Framework |
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13 requirements for GUI applications</title><prolog><metadata><keywords/></metadata></prolog><conbody> |
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14 <p>Applications developed for the Symbian platform can use a number of |
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15 different architecture solutions to meet their requirements. One example of |
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16 a common approach includes the Model - View - Controller (MVC) pattern used |
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17 in GUI-based applications. In this approach, the application is split into |
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18 three separate logical parts. Each part contains a different aspect of the |
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19 entire application, and has a specific role.</p> |
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20 <fig id="GUID-5E3A844B-CCF3-4F2A-82A9-DA7A5B65A572"><title>Logical dependencies in the MVC pattern</title><image href="GUID-A5E152B2-F15C-4809-A52A-BCDDBCD93255_d0e41998_href.png"/></fig> |
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21 <p>In this approach, the model:</p> |
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22 <ul> |
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23 <li><p>contains and manipulates the data in the application</p> |
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24 </li> |
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25 <li><p>is owned by the controller</p></li> |
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26 <li><p>is typically implemented in its own class or classes</p> |
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27 </li> |
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28 </ul> |
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29 <p>the <xref href="GUID-DAC32BB9-C0EB-42FF-A596-C2F1A90A4BD7.dita">view</xref> :</p> |
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30 <ul> |
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31 <li><p>displays the application state known by the model</p> |
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32 </li> |
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33 <li><p>receives user input</p></li> |
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34 <li><p>notifies the controller of relevant events</p></li> |
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35 <li><p>is implemented either with a <parmname>CCoeControl</parmname> derived |
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36 class or a <parmname>CAknView</parmname> derived class.</p><p>For more |
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37 information on these options, see <xref href="GUID-B5DE1C86-2B16-4B22-887F-7079E54A8ED6.dita">Traditional |
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38 Symbian UI application architecture</xref> and <xref href="GUID-68B999C2-0993-4804-9624-42C3D88BE5C7.dita">View |
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39 architecture</xref>.</p></li> |
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40 </ul> |
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41 <p>the <xref href="GUID-FD2CDEB8-0784-4BE5-A775-170F57D71BBC.dita">controller</xref> :</p> |
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42 <ul> |
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43 <li><p>handles application-wide events</p></li> |
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44 <li><p>commands the model, typically based on user input</p> |
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45 </li> |
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46 <li><p>selects the view to be displayed</p></li> |
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47 <li><p>is implemented either with a <xref href="GUID-77329067-34D9-3698-B764-294535E660EB.dita"><apiname>CAknAppUi</apiname></xref>-derived |
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48 class or a <xref href="GUID-2DBA2DA9-3DA7-381C-842C-9F6FEEDF973E.dita"><apiname>CAknViewAppUi</apiname></xref> derived class.</p><p>For |
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49 more information on these options, see <xref href="GUID-B5DE1C86-2B16-4B22-887F-7079E54A8ED6.dita">Traditional |
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50 Symbian UI application architecture</xref> and <xref href="GUID-68B999C2-0993-4804-9624-42C3D88BE5C7.dita">View |
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51 architecture</xref>.</p></li> |
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52 <li><p>requires the implementation of <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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53 classes.</p></li> |
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54 </ul> |
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55 <p>The pattern is implemented with the following classes.</p> |
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56 <fig id="GUID-B4508A88-B688-4BB7-B42A-31BFF41CD4FA"><title>Relationship between the classes that make up a typical Symbian application</title><image href="GUID-36BB14BD-34B3-4F5D-A670-707710E57585_d0e42116_href.png"/></fig> |
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57 <p>The <xref href="GUID-4F825D83-47A4-36C9-9A25-943A6D799F84.dita"><apiname>CAknApplication</apiname></xref>-derived class:</p> |
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58 <ul> |
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59 <li><p>provides the application object expected by the application |
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60 framework when the application is launched.</p></li> |
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61 <li><p>defines the application properties.</p></li> |
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62 <li><p>creates the <xref href="GUID-935C59EE-AD66-33FE-987B-BD97F5147CC1.dita"><apiname>CAknDocument</apiname></xref> derived class |
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63 if it does not exist yet.</p></li> |
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64 <li><p>if an instance of the application is already running, switches |
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65 to that instance and exits.</p></li> |
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66 </ul> |
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67 <p>The <xref href="GUID-935C59EE-AD66-33FE-987B-BD97F5147CC1.dita"><apiname>CAknDocument</apiname></xref>-derived class:</p> |
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68 <ul> |
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69 <li><p>creates the controller class</p></li> |
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70 <li><p>is the base class for application documents</p></li> |
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71 </ul> |
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72 </conbody></concept> |