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<td >Qt 5.12</td><td ><a href="qtwidgets-index.html">Qt Widgets</a></td><td >Part 7 - Additional Features</td></tr></table><table class="buildversion"><tr>
<td id="buildversion" width="100%" align="right"><a href="qtwidgets-index.html">Qt 5.12.6 Reference Documentation</a></td>
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<h3><a name="toc">Contents</a></h3>
<ul>
<li class="level1"><a href="#defining-the-addressbook-class">Defining the AddressBook Class</a></li>
<li class="level1"><a href="#implementing-the-addressbook-class">Implementing the AddressBook Class</a></li>
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<h1 class="title">Part 7 - Additional Features</h1>
<span class="subtitle"></span>
<!-- $$$tutorials/addressbook/part7-brief -->
<p>Describes how to export data in VCard format.</p>
<!-- @@@tutorials/addressbook/part7 -->
<!-- $$$tutorials/addressbook/part7-description -->
<div class="descr"> <a name="details"></a>
<p>This part covers some additional features that make the address book more convenient for the frequent user.</p>
<p class="centerAlign"><img src="images/addressbook-tutorial-part7-screenshot.png" alt="" /></p><p>Although our address book is useful in isolation, it would be better if we could exchange contact data with other applications. The vCard format is a popular file format that can be used for this purpose. Here we extend our address book client to allow contacts to be exported to vCard <code>.vcf</code> files.</p>
<a name="defining-the-addressbook-class"></a>
<h2 id="defining-the-addressbook-class">Defining the AddressBook Class</h2>
<p>We add a <a href="qpushbutton.html">QPushButton</a> object, <code>exportButton</code>, and a corresponding public slot, <code>exportAsVCard()</code> to our <code>AddressBook</code> class in the <code>addressbook.h</code> file.</p>
<pre class="cpp">
<span class="type">void</span> exportAsVCard();
...
<span class="type"><a href="qpushbutton.html">QPushButton</a></span> <span class="operator">*</span>exportButton;
</pre>
<a name="implementing-the-addressbook-class"></a>
<h2 id="implementing-the-addressbook-class">Implementing the AddressBook Class</h2>
<p>Within the <code>AddressBook</code> constructor, we connect <code>exportButton</code>'s <a href="qabstractbutton.html#clicked">clicked()</a> signal to <code>exportAsVCard()</code>. We also add this button to our <code>buttonLayout1</code>, the layout responsible for our panel of buttons on the right.</p>
<p>In our <code>exportAsVCard()</code> function, we start by extracting the contact's name into <code>name</code>. We declare <code>firstName</code>, <code>lastName</code> and <code>nameList</code>. Next, we look for the index of the first white space in <code>name</code>. If there is a white space, we split the contact's name into <code>firstName</code> and <code>lastName</code>. Then, we replace the space with an underscore ("_"). Alternately, if there is no white space, we assume that the contact only has a first name.</p>
<pre class="cpp">
<span class="type">void</span> AddressBook<span class="operator">::</span>exportAsVCard()
{
<span class="type"><a href="../qtcore/qstring.html">QString</a></span> name <span class="operator">=</span> nameLine<span class="operator">-</span><span class="operator">></span>text();
<span class="type"><a href="../qtcore/qstring.html">QString</a></span> address <span class="operator">=</span> addressText<span class="operator">-</span><span class="operator">></span>toPlainText();
<span class="type"><a href="../qtcore/qstring.html">QString</a></span> firstName;
<span class="type"><a href="../qtcore/qstring.html">QString</a></span> lastName;
<span class="type"><a href="../qtcore/qstringlist.html">QStringList</a></span> nameList;
<span class="type">int</span> index <span class="operator">=</span> name<span class="operator">.</span>indexOf(<span class="string">" "</span>);
<span class="keyword">if</span> (index <span class="operator">!</span><span class="operator">=</span> <span class="operator">-</span><span class="number">1</span>) {
nameList <span class="operator">=</span> name<span class="operator">.</span>split(<span class="type"><a href="../qtcore/qregularexpression.html">QRegularExpression</a></span>(<span class="string">"\\s+"</span>)<span class="operator">,</span> <span class="type"><a href="../qtcore/qstring.html">QString</a></span><span class="operator">::</span>SkipEmptyParts);
firstName <span class="operator">=</span> nameList<span class="operator">.</span>first();
lastName <span class="operator">=</span> nameList<span class="operator">.</span>last();
} <span class="keyword">else</span> {
firstName <span class="operator">=</span> name;
lastName <span class="operator">=</span> <span class="string">""</span>;
}
<span class="type"><a href="../qtcore/qstring.html">QString</a></span> fileName <span class="operator">=</span> <span class="type"><a href="qfiledialog.html">QFileDialog</a></span><span class="operator">::</span>getSaveFileName(<span class="keyword">this</span><span class="operator">,</span>
tr(<span class="string">"Export Contact"</span>)<span class="operator">,</span> <span class="string">""</span><span class="operator">,</span>
tr(<span class="string">"vCard Files (*.vcf);;All Files (*)"</span>));
<span class="keyword">if</span> (fileName<span class="operator">.</span>isEmpty())
<span class="keyword">return</span>;
<span class="type"><a href="../qtcore/qfile.html">QFile</a></span> file(fileName);
</pre>
<p>As with the <code>saveToFile()</code> function, we open a file dialog to let the user choose a location for the file. Using the file name chosen, we create an instance of <a href="../qtcore/qfile.html">QFile</a> to write to.</p>
<p>We attempt to open the file in <a href="../qtcore/qiodevice.html#OpenModeFlag-enum">WriteOnly</a> mode. If this process fails, we display a <a href="qmessagebox.html">QMessageBox</a> to inform the user about the problem and return. Otherwise, we pass the file as a parameter to a <a href="../qtcore/qtextstream.html">QTextStream</a> object, <code>out</code>. Like <a href="../qtcore/qdatastream.html">QDataStream</a>, the <a href="../qtcore/qtextstream.html">QTextStream</a> class provides functionality to read and write plain text to files. As a result, the <code>.vcf</code> file generated can be opened for editing in a text editor.</p>
<pre class="cpp">
<span class="keyword">if</span> (<span class="operator">!</span>file<span class="operator">.</span>open(<span class="type"><a href="../qtcore/qiodevice.html">QIODevice</a></span><span class="operator">::</span>WriteOnly)) {
<span class="type"><a href="qmessagebox.html">QMessageBox</a></span><span class="operator">::</span>information(<span class="keyword">this</span><span class="operator">,</span> tr(<span class="string">"Unable to open file"</span>)<span class="operator">,</span>
file<span class="operator">.</span>errorString());
<span class="keyword">return</span>;
}
<span class="type"><a href="../qtcore/qtextstream.html">QTextStream</a></span> out(<span class="operator">&</span>file);
</pre>
<p>We then write out a vCard file with the <code>BEGIN:VCARD</code> tag, followed by the <code>VERSION:2.1</code> tag. The contact's name is written with the <code>N:</code> tag. For the <code>FN:</code> tag, which fills in the "File as" property of a vCard, we have to check whether the contact has a last name or not. If the contact does, we use the details in <code>nameList</code> to fill it. Otherwise, we write <code>firstName</code> only.</p>
<pre class="cpp">
out <span class="operator"><</span><span class="operator"><</span> <span class="string">"BEGIN:VCARD"</span> <span class="operator"><</span><span class="operator"><</span> <span class="char">'\n'</span>;
out <span class="operator"><</span><span class="operator"><</span> <span class="string">"VERSION:2.1"</span> <span class="operator"><</span><span class="operator"><</span> <span class="char">'\n'</span>;
out <span class="operator"><</span><span class="operator"><</span> <span class="string">"N:"</span> <span class="operator"><</span><span class="operator"><</span> lastName <span class="operator"><</span><span class="operator"><</span> <span class="char">';'</span> <span class="operator"><</span><span class="operator"><</span> firstName <span class="operator"><</span><span class="operator"><</span> <span class="char">'\n'</span>;
<span class="keyword">if</span> (<span class="operator">!</span>nameList<span class="operator">.</span>isEmpty())
out <span class="operator"><</span><span class="operator"><</span> <span class="string">"FN:"</span> <span class="operator"><</span><span class="operator"><</span> nameList<span class="operator">.</span>join(<span class="char">' '</span>) <span class="operator"><</span><span class="operator"><</span> <span class="char">'\n'</span>;
<span class="keyword">else</span>
out <span class="operator"><</span><span class="operator"><</span> <span class="string">"FN:"</span> <span class="operator"><</span><span class="operator"><</span> firstName <span class="operator"><</span><span class="operator"><</span> <span class="char">'\n'</span>;
</pre>
<p>We proceed to write the contact's address. The semicolons in the address are escaped with "\", the newlines are replaced with semicolons, and the commas are replaced with spaces. Lastly, we write the <code>ADR;HOME:;</code> tag, followed by <code>address</code> and then the <code>END:VCARD</code> tag.</p>
<pre class="cpp">
address<span class="operator">.</span>replace(<span class="string">";"</span><span class="operator">,</span> <span class="string">"\\;"</span><span class="operator">,</span> <span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>CaseInsensitive);
address<span class="operator">.</span>replace(<span class="char">'\n'</span><span class="operator">,</span> <span class="string">";"</span><span class="operator">,</span> <span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>CaseInsensitive);
address<span class="operator">.</span>replace(<span class="string">","</span><span class="operator">,</span> <span class="string">" "</span><span class="operator">,</span> <span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>CaseInsensitive);
out <span class="operator"><</span><span class="operator"><</span> <span class="string">"ADR;HOME:;"</span> <span class="operator"><</span><span class="operator"><</span> address <span class="operator"><</span><span class="operator"><</span> <span class="char">'\n'</span>;
out <span class="operator"><</span><span class="operator"><</span> <span class="string">"END:VCARD"</span> <span class="operator"><</span><span class="operator"><</span> <span class="char">'\n'</span>;
<span class="type"><a href="qmessagebox.html">QMessageBox</a></span><span class="operator">::</span>information(<span class="keyword">this</span><span class="operator">,</span> tr(<span class="string">"Export Successful"</span>)<span class="operator">,</span>
tr(<span class="string">"\"%1\" has been exported as a vCard."</span>)<span class="operator">.</span>arg(name));
}
</pre>
<p>In the end, a <a href="qmessagebox.html">QMessageBox</a> is displayed to inform the user that the vCard has been successfully exported.</p>
<p><i>vCard is a trademark of the <a href="http://www.imc.org">Internet Mail Consortium</a></i>.</p>
<p>Files:</p>
<ul>
<li><a href="qtwidgets-tutorials-addressbook-part7-addressbook-cpp.html">tutorials/addressbook/part7/addressbook.cpp</a></li>
<li><a href="qtwidgets-tutorials-addressbook-part7-addressbook-h.html">tutorials/addressbook/part7/addressbook.h</a></li>
<li><a href="qtwidgets-tutorials-addressbook-part7-finddialog-cpp.html">tutorials/addressbook/part7/finddialog.cpp</a></li>
<li><a href="qtwidgets-tutorials-addressbook-part7-finddialog-h.html">tutorials/addressbook/part7/finddialog.h</a></li>
<li><a href="qtwidgets-tutorials-addressbook-part7-main-cpp.html">tutorials/addressbook/part7/main.cpp</a></li>
<li><a href="qtwidgets-tutorials-addressbook-part7-part7-pro.html">tutorials/addressbook/part7/part7.pro</a></li>
</ul>
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<!-- @@@tutorials/addressbook/part7 -->
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