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| 6 | <title>Continuing Development</title>
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| 24 | <font color="#004faf">Main Classes</font></a>
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| 31 | </td>
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| 32 | <td align="right" valign="center"><img src="logo32.png" align="right" width="64" height="32" border="0"></td></tr></table><h1 align=center>Continuing Development</h1>
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| 33 |
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| 34 |
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| 35 |
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| 36 | [ <a href="motif-walkthrough-9.html">Previous: Replacing the Print Dialog</a> ]
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| 37 | [ <a href="motif-walkthrough.html">Home</a> ]
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| 38 | <p> We have not quite finished with the migration to Qt, even though our
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| 39 | project does not use <a href="motif-extension.html#Motif">Motif</a> any more. Qt provides many useful features
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| 40 | that we can begin using immediately. Some of the most interesting
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| 41 | ones are presented below as a guide for where to start extending your
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| 42 | existing projects.
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| 43 | <p> <h2> Using Unicode
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| 44 | </h2>
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| 45 | <a name="1"></a><p> Support for <a href="i18n.html">internationalization</a> is very easy
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| 46 | with Qt. Using <a href="qstring.html">QString</a> instead of <tt>char*</tt> for storing text gives
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| 47 | us support for most of the written languages around the world. Our <tt>Page</tt> and <tt>Options</tt> structs look much simpler now.
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| 48 | <p>
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| 49 |
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| 50 | <p> <pre></pre>
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| 51 | <p> <pre></pre>
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| 52 | <p> All functions that use the <tt>Page</tt> and <tt>Options</tt> structs need to be
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| 53 | updated to use QString properly. Since QString is also an <a href="shclass.html#implicitly-shared">implicitly shared</a> class, we no longer have to do any memory management with our
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| 54 | strings. We can remove all occurences of the <a href="qcstring.html#qstrdup">qstrdup</a>() function,
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| 55 | and we never need to use <em>new</em> or <em>delete</em> when done with a string.
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| 56 | QString will allocate and delete data when needed.
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| 57 | <p> Here are the <tt>MainWindow::fileOpen()</tt> and <tt>MainWindow::pageChange()</tt>
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| 58 | functions from <tt>mainwindow.ui.h</tt>. Notice that the code no longer
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| 59 | uses <em>delete</em> or <a href="qcstring.html#qstrdup">qstrdup</a>() when storing text.
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| 60 | <p>
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| 61 |
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| 62 | <p> <pre></pre>
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| 63 | <p> <pre>
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| 64 | ...
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| 65 | </pre>
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| 66 |
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| 67 | <p> <pre></pre>
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| 68 | <p> Almost all of the functions in our application are affected by this
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| 69 | change. In most cases, we end up removing more code than we are
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| 70 | adding. To keep the size of this walkthrough reasonable, we've only
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| 71 | shown a small portion of the required changes, since the changes are
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| 72 | very similar to those shown above.
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| 73 | <p> <h2> Writing Platform-Independent Code
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| 74 | </h2>
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| 75 | <a name="2"></a><p> Qt provides many <a href="io.html">input and output</a> classes. We
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| 76 | can use these in <tt>MainWindow::readDB()</tt> and <tt>MainWindow::saveDB()</tt>.
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| 77 | Currently, these functions use functions only found on UNIX machines.
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| 78 | Using <a href="qfile.html">QFile</a> and <a href="qtextstream.html">QTextStream</a> removes this dependency on UNIX, and we can
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| 79 | begin building and testing our application on Microsoft Windows and
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| 80 | Apple Mac OS X.
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| 81 | <p> The platform-independent versions of the <tt>MainWindow::readDB()</tt> and
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| 82 | <tt>MainWindow::saveDB()</tt> functions can be found in the <tt>io.cpp</tt> file.
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| 83 | <p> <h2> Designing a Modern User Interface
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| 84 | </h2>
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| 85 | <a name="3"></a><p> Since we used the <em>Qt Designer</em> to design the <em>Main Window</em>
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| 86 | widget, we can extend the interface easily. We can use some of the
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| 87 | more advanced features of <a href="qmainwindow.html">QMainWindow</a>, which includes dockable
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| 88 | toolbars. Adding these is simple with the <em>Qt Designer</em>. The
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| 89 | final version of our project includes a toolbar, which provides quick
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| 90 | access to the <em>Open</em>, <em>Save</em>, <em>Print</em>, <em>New Page</em> and <em>Delete to Trash</em> actions.
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| 91 | <p> The possibilities are endless. An <em>Edit</em> menu, with the common <em>Cut</em>, <em>Copy</em> and <em>Paste</em> actions, could be added in a relatively
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| 92 | short period of time. As our project expands to other platforms, we
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| 93 | could add menus and dialogs that allow us synchronize todo lists
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| 94 | between a normal desktop computer and a handheld device running with
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| 95 | Qt/Embedded.
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| 96 | <p> [ <a href="motif-walkthrough-9.html">Previous: Replacing the Print Dialog</a> ]
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| 97 | [ <a href="motif-walkthrough.html">Home</a> ]
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| 98 | <p>
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| 100 | <p><address><hr><div align=center>
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| 102 | <td>Copyright © 2007
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| 103 | <a href="troll.html">Trolltech</a><td align=center><a href="trademarks.html">Trademarks</a>
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| 104 | <td align=right><div align=right>Qt 3.3.8</div>
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