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<td >Qt 5.12</td><td ><a href="qtxml-index.html">Qt XML</a></td><td >QXmlStream Bookmarks Example</td></tr></table><table class="buildversion"><tr>
<td id="buildversion" width="100%" align="right"><a href="qtxml-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="#xbelwriter-class-definition">XbelWriter Class Definition</a></li>
<li class="level1"><a href="#xbelwriter-class-implementation">XbelWriter Class Implementation</a></li>
<li class="level1"><a href="#xbelreader-class-definition">XbelReader Class Definition</a></li>
<li class="level1"><a href="#xbelreader-class-implementation">XbelReader Class Implementation</a></li>
<li class="level1"><a href="#mainwindow-class-definition">MainWindow Class Definition</a></li>
<li class="level1"><a href="#mainwindow-class-implementation">MainWindow Class Implementation</a></li>
<li class="level1"><a href="#main-function"><code>main()</code> Function</a></li>
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<h1 class="title">QXmlStream Bookmarks Example</h1>
<span class="subtitle"></span>
<!-- $$$streambookmarks-brief -->
<p>Demonstrates how to read and write to XBEL files.</p>
<!-- @@@streambookmarks -->
<!-- $$$streambookmarks-description -->
<div class="descr"> <a name="details"></a>
<p>The QXmlStream Bookmarks example provides a reader for XML Bookmark Exchange Language (XBEL) files using Qt's <a href="../qtcore/qxmlstreamreader.html">QXmlStreamReader</a> class for reading, and <a href="../qtcore/qxmlstreamwriter.html">QXmlStreamWriter</a> class for writing the files.</p>
<p class="centerAlign"><img src="images/xmlstreamexample-screenshot.png" alt="" /></p><a name="xbelwriter-class-definition"></a>
<h2 id="xbelwriter-class-definition">XbelWriter Class Definition</h2>
<p>The <code>XbelWriter</code> class contains a private instance of <a href="../qtcore/qxmlstreamwriter.html">QXmlStreamWriter</a>, which provides an XML writer with a streaming API. <code>XbelWriter</code> also has a reference to the <a href="../qtwidgets/qtreewidget.html">QTreeWidget</a> instance where the bookmark hierarchy is stored.</p>
<pre class="cpp">
<span class="keyword">class</span> XbelWriter
{
<span class="keyword">public</span>:
<span class="keyword">explicit</span> XbelWriter(<span class="keyword">const</span> <span class="type"><a href="../qtwidgets/qtreewidget.html">QTreeWidget</a></span> <span class="operator">*</span>treeWidget);
bool writeFile(<span class="type"><a href="../qtcore/qiodevice.html">QIODevice</a></span> <span class="operator">*</span>device);
<span class="keyword">private</span>:
<span class="type">void</span> writeItem(<span class="keyword">const</span> <span class="type"><a href="../qtwidgets/qtreewidgetitem.html">QTreeWidgetItem</a></span> <span class="operator">*</span>item);
<span class="type"><a href="../qtcore/qxmlstreamwriter.html">QXmlStreamWriter</a></span> xml;
<span class="keyword">const</span> <span class="type"><a href="../qtwidgets/qtreewidget.html">QTreeWidget</a></span> <span class="operator">*</span>treeWidget;
};
</pre>
<a name="xbelwriter-class-implementation"></a>
<h2 id="xbelwriter-class-implementation">XbelWriter Class Implementation</h2>
<p>The <code>XbelWriter</code> constructor accepts a <i>treeWidget</i> to initialize within its definition. We enable <a href="../qtcore/qxmlstreamwriter.html">QXmlStreamWriter</a>'s auto-formatting property to ensure line-breaks and indentations are added automatically to empty sections between elements, increasing readability as the data is split into several lines.</p>
<pre class="cpp">
XbelWriter<span class="operator">::</span>XbelWriter(<span class="keyword">const</span> <span class="type"><a href="../qtwidgets/qtreewidget.html">QTreeWidget</a></span> <span class="operator">*</span>treeWidget)
: treeWidget(treeWidget)
{
xml<span class="operator">.</span>setAutoFormatting(<span class="keyword">true</span>);
}
</pre>
<p>The <code>writeFile()</code> function accepts a <a href="../qtcore/qiodevice.html">QIODevice</a> object and sets it using <code>setDevice()</code>. This function then writes the document type definition(DTD), the start element, the version, and <code>treeWidget</code>'s top-level items.</p>
<pre class="cpp">
bool XbelWriter<span class="operator">::</span>writeFile(<span class="type"><a href="../qtcore/qiodevice.html">QIODevice</a></span> <span class="operator">*</span>device)
{
xml<span class="operator">.</span>setDevice(device);
xml<span class="operator">.</span>writeStartDocument();
xml<span class="operator">.</span>writeDTD(<span class="type"><a href="../qtcore/qstring.html#QStringLiteral">QStringLiteral</a></span>(<span class="string">"<!DOCTYPE xbel>"</span>));
xml<span class="operator">.</span>writeStartElement(<span class="type"><a href="../qtcore/qstring.html#QStringLiteral">QStringLiteral</a></span>(<span class="string">"xbel"</span>));
xml<span class="operator">.</span>writeAttribute(XbelReader<span class="operator">::</span>versionAttribute()<span class="operator">,</span> <span class="type"><a href="../qtcore/qstring.html#QStringLiteral">QStringLiteral</a></span>(<span class="string">"1.0"</span>));
<span class="keyword">for</span> (<span class="type">int</span> i <span class="operator">=</span> <span class="number">0</span>; i <span class="operator"><</span> treeWidget<span class="operator">-</span><span class="operator">></span>topLevelItemCount(); <span class="operator">+</span><span class="operator">+</span>i)
writeItem(treeWidget<span class="operator">-</span><span class="operator">></span>topLevelItem(i));
xml<span class="operator">.</span>writeEndDocument();
<span class="keyword">return</span> <span class="keyword">true</span>;
}
</pre>
<p>The <code>writeItem()</code> function accepts a <a href="../qtwidgets/qtreewidgetitem.html">QTreeWidgetItem</a> object and writes it to the stream, depending on its <code>tagName</code>, which can either be a "folder", "bookmark", or "separator".</p>
<pre class="cpp">
<span class="type">void</span> XbelWriter<span class="operator">::</span>writeItem(<span class="keyword">const</span> <span class="type"><a href="../qtwidgets/qtreewidgetitem.html">QTreeWidgetItem</a></span> <span class="operator">*</span>item)
{
<span class="type"><a href="../qtcore/qstring.html">QString</a></span> tagName <span class="operator">=</span> item<span class="operator">-</span><span class="operator">></span>data(<span class="number">0</span><span class="operator">,</span> <span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>UserRole)<span class="operator">.</span>toString();
<span class="keyword">if</span> (tagName <span class="operator">=</span><span class="operator">=</span> QLatin1String(<span class="string">"folder"</span>)) {
bool folded <span class="operator">=</span> <span class="operator">!</span>treeWidget<span class="operator">-</span><span class="operator">></span>isItemExpanded(item);
xml<span class="operator">.</span>writeStartElement(tagName);
xml<span class="operator">.</span>writeAttribute(XbelReader<span class="operator">::</span>foldedAttribute()<span class="operator">,</span> folded <span class="operator">?</span> yesValue() : noValue());
xml<span class="operator">.</span>writeTextElement(titleElement()<span class="operator">,</span> item<span class="operator">-</span><span class="operator">></span>text(<span class="number">0</span>));
<span class="keyword">for</span> (<span class="type">int</span> i <span class="operator">=</span> <span class="number">0</span>; i <span class="operator"><</span> item<span class="operator">-</span><span class="operator">></span>childCount(); <span class="operator">+</span><span class="operator">+</span>i)
writeItem(item<span class="operator">-</span><span class="operator">></span>child(i));
xml<span class="operator">.</span>writeEndElement();
} <span class="keyword">else</span> <span class="keyword">if</span> (tagName <span class="operator">=</span><span class="operator">=</span> QLatin1String(<span class="string">"bookmark"</span>)) {
xml<span class="operator">.</span>writeStartElement(tagName);
<span class="keyword">if</span> (<span class="operator">!</span>item<span class="operator">-</span><span class="operator">></span>text(<span class="number">1</span>)<span class="operator">.</span>isEmpty())
xml<span class="operator">.</span>writeAttribute(XbelReader<span class="operator">::</span>hrefAttribute()<span class="operator">,</span> item<span class="operator">-</span><span class="operator">></span>text(<span class="number">1</span>));
xml<span class="operator">.</span>writeTextElement(titleElement()<span class="operator">,</span> item<span class="operator">-</span><span class="operator">></span>text(<span class="number">0</span>));
xml<span class="operator">.</span>writeEndElement();
} <span class="keyword">else</span> <span class="keyword">if</span> (tagName <span class="operator">=</span><span class="operator">=</span> QLatin1String(<span class="string">"separator"</span>)) {
xml<span class="operator">.</span>writeEmptyElement(tagName);
}
}
</pre>
<a name="xbelreader-class-definition"></a>
<h2 id="xbelreader-class-definition">XbelReader Class Definition</h2>
<p>The <code>XbelReader</code> contains a private instance of <a href="../qtcore/qxmlstreamreader.html">QXmlStreamReader</a>, the companion class to <a href="../qtcore/qxmlstreamwriter.html">QXmlStreamWriter</a>. <code>XbelReader</code> also contains a reference to the <a href="../qtwidgets/qtreewidget.html">QTreeWidget</a> that is used to group the bookmarks according to their hierarchy.</p>
<pre class="cpp">
<span class="keyword">class</span> XbelReader
{
<span class="keyword">public</span>:
XbelReader(<span class="type"><a href="../qtwidgets/qtreewidget.html">QTreeWidget</a></span> <span class="operator">*</span>treeWidget);
bool read(<span class="type"><a href="../qtcore/qiodevice.html">QIODevice</a></span> <span class="operator">*</span>device);
<span class="type"><a href="../qtcore/qstring.html">QString</a></span> errorString() <span class="keyword">const</span>;
<span class="keyword">static</span> <span class="keyword">inline</span> <span class="type"><a href="../qtcore/qstring.html">QString</a></span> versionAttribute() { <span class="keyword">return</span> <span class="type"><a href="../qtcore/qstring.html#QStringLiteral">QStringLiteral</a></span>(<span class="string">"version"</span>); }
<span class="keyword">static</span> <span class="keyword">inline</span> <span class="type"><a href="../qtcore/qstring.html">QString</a></span> hrefAttribute() { <span class="keyword">return</span> <span class="type"><a href="../qtcore/qstring.html#QStringLiteral">QStringLiteral</a></span>(<span class="string">"href"</span>); }
<span class="keyword">static</span> <span class="keyword">inline</span> <span class="type"><a href="../qtcore/qstring.html">QString</a></span> foldedAttribute() { <span class="keyword">return</span> <span class="type"><a href="../qtcore/qstring.html#QStringLiteral">QStringLiteral</a></span>(<span class="string">"folded"</span>); }
<span class="keyword">private</span>:
<span class="type">void</span> readXBEL();
<span class="type">void</span> readTitle(<span class="type"><a href="../qtwidgets/qtreewidgetitem.html">QTreeWidgetItem</a></span> <span class="operator">*</span>item);
<span class="type">void</span> readSeparator(<span class="type"><a href="../qtwidgets/qtreewidgetitem.html">QTreeWidgetItem</a></span> <span class="operator">*</span>item);
<span class="type">void</span> readFolder(<span class="type"><a href="../qtwidgets/qtreewidgetitem.html">QTreeWidgetItem</a></span> <span class="operator">*</span>item);
<span class="type">void</span> readBookmark(<span class="type"><a href="../qtwidgets/qtreewidgetitem.html">QTreeWidgetItem</a></span> <span class="operator">*</span>item);
<span class="type"><a href="../qtwidgets/qtreewidgetitem.html">QTreeWidgetItem</a></span> <span class="operator">*</span>createChildItem(<span class="type"><a href="../qtwidgets/qtreewidgetitem.html">QTreeWidgetItem</a></span> <span class="operator">*</span>item);
<span class="type"><a href="../qtcore/qxmlstreamreader.html">QXmlStreamReader</a></span> xml;
<span class="type"><a href="../qtwidgets/qtreewidget.html">QTreeWidget</a></span> <span class="operator">*</span>treeWidget;
<span class="type">QIcon</span> folderIcon;
<span class="type">QIcon</span> bookmarkIcon;
};
</pre>
<a name="xbelreader-class-implementation"></a>
<h2 id="xbelreader-class-implementation">XbelReader Class Implementation</h2>
<p>The <code>XbelReader</code> constructor accepts a <a href="../qtwidgets/qtreewidget.html">QTreeWidget</a> to initialize the <code>treeWidget</code> within its definition. A <a href="../qtwidgets/qstyle.html">QStyle</a> object is used to set <code>treeWidget</code>'s style property. The <code>folderIcon</code> is set to QIcon::Normal mode where the pixmap is only displayed when the user is not interacting with the icon. The <a href="../qtwidgets/qstyle.html#StandardPixmap-enum">QStyle::SP_DirClosedIcon</a>, <a href="../qtwidgets/qstyle.html#StandardPixmap-enum">QStyle::SP_DirOpenIcon</a>, and <a href="../qtwidgets/qstyle.html#StandardPixmap-enum">QStyle::SP_FileIcon</a> correspond to standard pixmaps that follow the style of your GUI.</p>
<pre class="cpp">
XbelReader<span class="operator">::</span>XbelReader(<span class="type"><a href="../qtwidgets/qtreewidget.html">QTreeWidget</a></span> <span class="operator">*</span>treeWidget)
: treeWidget(treeWidget)
{
<span class="type"><a href="../qtwidgets/qstyle.html">QStyle</a></span> <span class="operator">*</span>style <span class="operator">=</span> treeWidget<span class="operator">-</span><span class="operator">></span>style();
folderIcon<span class="operator">.</span>addPixmap(style<span class="operator">-</span><span class="operator">></span>standardPixmap(<span class="type"><a href="../qtwidgets/qstyle.html">QStyle</a></span><span class="operator">::</span>SP_DirClosedIcon)<span class="operator">,</span>
<span class="type">QIcon</span><span class="operator">::</span>Normal<span class="operator">,</span> <span class="type">QIcon</span><span class="operator">::</span>Off);
folderIcon<span class="operator">.</span>addPixmap(style<span class="operator">-</span><span class="operator">></span>standardPixmap(<span class="type"><a href="../qtwidgets/qstyle.html">QStyle</a></span><span class="operator">::</span>SP_DirOpenIcon)<span class="operator">,</span>
<span class="type">QIcon</span><span class="operator">::</span>Normal<span class="operator">,</span> <span class="type">QIcon</span><span class="operator">::</span>On);
bookmarkIcon<span class="operator">.</span>addPixmap(style<span class="operator">-</span><span class="operator">></span>standardPixmap(<span class="type"><a href="../qtwidgets/qstyle.html">QStyle</a></span><span class="operator">::</span>SP_FileIcon));
}
</pre>
<p>The <code>read()</code> function accepts a <a href="../qtcore/qiodevice.html">QIODevice</a> and sets it using <a href="../qtcore/qxmlstreamreader.html#setDevice">setDevice()</a>. The actual process of reading only takes place if the file is a valid XBEL 1.0 file. Note that the XML input needs to be well-formed to be accepted by <a href="../qtcore/qxmlstreamreader.html">QXmlStreamReader</a>. Otherwise, the <a href="../qtcore/qxmlstreamreader.html#raiseError">raiseError()</a> function is used to display an error message. Since the XBEL reader is only concerned with reading XML elements, it makes extensive use of the <a href="../qtcore/qxmlstreamreader.html#readNextStartElement">readNextStartElement()</a> convenience function.</p>
<pre class="cpp">
bool XbelReader<span class="operator">::</span>read(<span class="type"><a href="../qtcore/qiodevice.html">QIODevice</a></span> <span class="operator">*</span>device)
{
xml<span class="operator">.</span>setDevice(device);
<span class="keyword">if</span> (xml<span class="operator">.</span>readNextStartElement()) {
<span class="keyword">if</span> (xml<span class="operator">.</span>name() <span class="operator">=</span><span class="operator">=</span> QLatin1String(<span class="string">"xbel"</span>)
<span class="operator">&</span><span class="operator">&</span> xml<span class="operator">.</span>attributes()<span class="operator">.</span>value(versionAttribute()) <span class="operator">=</span><span class="operator">=</span> QLatin1String(<span class="string">"1.0"</span>)) {
readXBEL();
} <span class="keyword">else</span> {
xml<span class="operator">.</span>raiseError(<span class="type"><a href="../qtcore/qobject.html">QObject</a></span><span class="operator">::</span>tr(<span class="string">"The file is not an XBEL version 1.0 file."</span>));
}
}
<span class="keyword">return</span> <span class="operator">!</span>xml<span class="operator">.</span>error();
}
</pre>
<p>The <code>errorString()</code> function is used if an error occurred, in order to obtain a description of the error complete with line and column number information.</p>
<pre class="cpp">
<span class="type"><a href="../qtcore/qstring.html">QString</a></span> XbelReader<span class="operator">::</span>errorString() <span class="keyword">const</span>
{
<span class="keyword">return</span> <span class="type"><a href="../qtcore/qobject.html">QObject</a></span><span class="operator">::</span>tr(<span class="string">"%1\nLine %2, column %3"</span>)
<span class="operator">.</span>arg(xml<span class="operator">.</span>errorString())
<span class="operator">.</span>arg(xml<span class="operator">.</span>lineNumber())
<span class="operator">.</span>arg(xml<span class="operator">.</span>columnNumber());
}
</pre>
<p>The <code>readXBEL()</code> function reads the name of a startElement and calls the appropriate function to read it, depending on whether if its a "folder", "bookmark" or "separator". Otherwise, it calls <a href="../qtcore/qxmlstreamreader.html#skipCurrentElement">skipCurrentElement()</a>. The <a href="../qtcore/qtglobal.html#Q_ASSERT">Q_ASSERT</a>() macro is used to provide a pre-condition for the function.</p>
<pre class="cpp">
<span class="type">void</span> XbelReader<span class="operator">::</span>readXBEL()
{
Q_ASSERT(xml<span class="operator">.</span>isStartElement() <span class="operator">&</span><span class="operator">&</span> xml<span class="operator">.</span>name() <span class="operator">=</span><span class="operator">=</span> QLatin1String(<span class="string">"xbel"</span>));
<span class="keyword">while</span> (xml<span class="operator">.</span>readNextStartElement()) {
<span class="keyword">if</span> (xml<span class="operator">.</span>name() <span class="operator">=</span><span class="operator">=</span> QLatin1String(<span class="string">"folder"</span>))
readFolder(<span class="number">0</span>);
<span class="keyword">else</span> <span class="keyword">if</span> (xml<span class="operator">.</span>name() <span class="operator">=</span><span class="operator">=</span> QLatin1String(<span class="string">"bookmark"</span>))
readBookmark(<span class="number">0</span>);
<span class="keyword">else</span> <span class="keyword">if</span> (xml<span class="operator">.</span>name() <span class="operator">=</span><span class="operator">=</span> QLatin1String(<span class="string">"separator"</span>))
readSeparator(<span class="number">0</span>);
<span class="keyword">else</span>
xml<span class="operator">.</span>skipCurrentElement();
}
}
</pre>
<p>The <code>readTitle()</code> function reads the bookmark's title.</p>
<pre class="cpp">
<span class="type">void</span> XbelReader<span class="operator">::</span>readTitle(<span class="type"><a href="../qtwidgets/qtreewidgetitem.html">QTreeWidgetItem</a></span> <span class="operator">*</span>item)
{
Q_ASSERT(xml<span class="operator">.</span>isStartElement() <span class="operator">&</span><span class="operator">&</span> xml<span class="operator">.</span>name() <span class="operator">=</span><span class="operator">=</span> QLatin1String(<span class="string">"title"</span>));
<span class="type"><a href="../qtcore/qstring.html">QString</a></span> title <span class="operator">=</span> xml<span class="operator">.</span>readElementText();
item<span class="operator">-</span><span class="operator">></span>setText(<span class="number">0</span><span class="operator">,</span> title);
}
</pre>
<p>The <code>readSeparator()</code> function creates a separator and sets its flags. The text is set to 30 "0xB7", the HEX equivalent for period. The element is then skipped using <a href="../qtcore/qxmlstreamreader.html#skipCurrentElement">skipCurrentElement()</a>.</p>
<pre class="cpp">
<span class="type">void</span> XbelReader<span class="operator">::</span>readSeparator(<span class="type"><a href="../qtwidgets/qtreewidgetitem.html">QTreeWidgetItem</a></span> <span class="operator">*</span>item)
{
Q_ASSERT(xml<span class="operator">.</span>isStartElement() <span class="operator">&</span><span class="operator">&</span> xml<span class="operator">.</span>name() <span class="operator">=</span><span class="operator">=</span> QLatin1String(<span class="string">"separator"</span>));
<span class="type"><a href="../qtwidgets/qtreewidgetitem.html">QTreeWidgetItem</a></span> <span class="operator">*</span>separator <span class="operator">=</span> createChildItem(item);
separator<span class="operator">-</span><span class="operator">></span>setFlags(item<span class="operator">-</span><span class="operator">></span>flags() <span class="operator">&</span> <span class="operator">~</span><span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>ItemIsSelectable);
separator<span class="operator">-</span><span class="operator">></span>setText(<span class="number">0</span><span class="operator">,</span> <span class="type"><a href="../qtcore/qstring.html">QString</a></span>(<span class="number">30</span><span class="operator">,</span> <span class="number">0xB7</span>));
xml<span class="operator">.</span>skipCurrentElement();
}
</pre>
<a name="mainwindow-class-definition"></a>
<h2 id="mainwindow-class-definition">MainWindow Class Definition</h2>
<p>The <code>MainWindow</code> class is a subclass of <a href="../qtwidgets/qmainwindow.html">QMainWindow</a>, with a <code>File</code> menu and a <code>Help</code> menu.</p>
<pre class="cpp">
<span class="keyword">class</span> MainWindow : <span class="keyword">public</span> <span class="type"><a href="../qtwidgets/qmainwindow.html">QMainWindow</a></span>
{
Q_OBJECT
<span class="keyword">public</span>:
MainWindow();
<span class="keyword">public</span> <span class="keyword">slots</span>:
<span class="type">void</span> open();
<span class="type">void</span> saveAs();
<span class="type">void</span> about();
<span class="preprocessor">#if !defined(QT_NO_CONTEXTMENU) && !defined(QT_NO_CLIPBOARD)</span>
<span class="type">void</span> onCustomContextMenuRequested(<span class="keyword">const</span> <span class="type"><a href="../qtcore/qpoint.html">QPoint</a></span> <span class="operator">&</span>pos);
<span class="preprocessor">#endif</span>
<span class="keyword">private</span>:
<span class="type">void</span> createMenus();
<span class="type"><a href="../qtwidgets/qtreewidget.html">QTreeWidget</a></span> <span class="operator">*</span>treeWidget;
};
</pre>
<a name="mainwindow-class-implementation"></a>
<h2 id="mainwindow-class-implementation">MainWindow Class Implementation</h2>
<p>The <code>MainWindow</code> constructor instantiates the <a href="../qtwidgets/qtreewidget.html">QTreeWidget</a> object, <code>treeWidget</code> and sets its header with a <a href="../qtcore/qstringlist.html">QStringList</a> object, <code>labels</code>. The constructor also invokes <code>createActions()</code> and <code>createMenus()</code> to set up the menus and their corresponding actions. The <code>statusBar()</code> is used to display the message "Ready" and the window's size is fixed to 480x320 pixels.</p>
<pre class="cpp">
MainWindow<span class="operator">::</span>MainWindow()
{
<span class="type"><a href="../qtcore/qstringlist.html">QStringList</a></span> labels;
labels <span class="operator"><</span><span class="operator"><</span> tr(<span class="string">"Title"</span>) <span class="operator"><</span><span class="operator"><</span> tr(<span class="string">"Location"</span>);
treeWidget <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="../qtwidgets/qtreewidget.html">QTreeWidget</a></span>;
treeWidget<span class="operator">-</span><span class="operator">></span>header()<span class="operator">-</span><span class="operator">></span>setSectionResizeMode(<span class="type"><a href="../qtwidgets/qheaderview.html">QHeaderView</a></span><span class="operator">::</span>Stretch);
treeWidget<span class="operator">-</span><span class="operator">></span>setHeaderLabels(labels);
<span class="preprocessor">#if !defined(QT_NO_CONTEXTMENU) && !defined(QT_NO_CLIPBOARD)</span>
treeWidget<span class="operator">-</span><span class="operator">></span>setContextMenuPolicy(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>CustomContextMenu);
connect(treeWidget<span class="operator">,</span> <span class="operator">&</span><span class="type"><a href="../qtwidgets/qwidget.html">QWidget</a></span><span class="operator">::</span>customContextMenuRequested<span class="operator">,</span>
<span class="keyword">this</span><span class="operator">,</span> <span class="operator">&</span>MainWindow<span class="operator">::</span>onCustomContextMenuRequested);
<span class="preprocessor">#endif</span>
setCentralWidget(treeWidget);
createMenus();
statusBar()<span class="operator">-</span><span class="operator">></span>showMessage(tr(<span class="string">"Ready"</span>));
setWindowTitle(tr(<span class="string">"QXmlStream Bookmarks"</span>));
<span class="keyword">const</span> <span class="type"><a href="../qtcore/qsize.html">QSize</a></span> availableSize <span class="operator">=</span> <span class="type"><a href="../qtwidgets/qapplication.html">QApplication</a></span><span class="operator">::</span>desktop()<span class="operator">-</span><span class="operator">></span>availableGeometry(<span class="keyword">this</span>)<span class="operator">.</span>size();
resize(availableSize<span class="operator">.</span>width() <span class="operator">/</span> <span class="number">2</span><span class="operator">,</span> availableSize<span class="operator">.</span>height() <span class="operator">/</span> <span class="number">3</span>);
}
</pre>
<p>The <code>open()</code> function enables the user to open an XBEL file using <a href="../qtwidgets/qfiledialog.html#getOpenFileName">QFileDialog::getOpenFileName</a>(). A warning message is displayed along with the <code>fileName</code> and <code>errorString</code> if the file cannot be read or if there is a parse error.</p>
<pre class="cpp">
<span class="type">void</span> MainWindow<span class="operator">::</span>open()
{
<span class="type"><a href="../qtcore/qstring.html">QString</a></span> fileName <span class="operator">=</span>
<span class="type"><a href="../qtwidgets/qfiledialog.html">QFileDialog</a></span><span class="operator">::</span>getOpenFileName(<span class="keyword">this</span><span class="operator">,</span> tr(<span class="string">"Open Bookmark File"</span>)<span class="operator">,</span>
<span class="type"><a href="../qtcore/qdir.html">QDir</a></span><span class="operator">::</span>currentPath()<span class="operator">,</span>
tr(<span class="string">"XBEL Files (*.xbel *.xml)"</span>));
<span class="keyword">if</span> (fileName<span class="operator">.</span>isEmpty())
<span class="keyword">return</span>;
treeWidget<span class="operator">-</span><span class="operator">></span>clear();
<span class="type"><a href="../qtcore/qfile.html">QFile</a></span> file(fileName);
<span class="keyword">if</span> (<span class="operator">!</span>file<span class="operator">.</span>open(<span class="type"><a href="../qtcore/qfile.html">QFile</a></span><span class="operator">::</span>ReadOnly <span class="operator">|</span> <span class="type"><a href="../qtcore/qfile.html">QFile</a></span><span class="operator">::</span>Text)) {
<span class="type"><a href="../qtwidgets/qmessagebox.html">QMessageBox</a></span><span class="operator">::</span>warning(<span class="keyword">this</span><span class="operator">,</span> tr(<span class="string">"QXmlStream Bookmarks"</span>)<span class="operator">,</span>
tr(<span class="string">"Cannot read file %1:\n%2."</span>)
<span class="operator">.</span>arg(<span class="type"><a href="../qtcore/qdir.html">QDir</a></span><span class="operator">::</span>toNativeSeparators(fileName)<span class="operator">,</span>
file<span class="operator">.</span>errorString()));
<span class="keyword">return</span>;
}
XbelReader reader(treeWidget);
<span class="keyword">if</span> (<span class="operator">!</span>reader<span class="operator">.</span>read(<span class="operator">&</span>file)) {
<span class="type"><a href="../qtwidgets/qmessagebox.html">QMessageBox</a></span><span class="operator">::</span>warning(<span class="keyword">this</span><span class="operator">,</span> tr(<span class="string">"QXmlStream Bookmarks"</span>)<span class="operator">,</span>
tr(<span class="string">"Parse error in file %1:\n\n%2"</span>)
<span class="operator">.</span>arg(<span class="type"><a href="../qtcore/qdir.html">QDir</a></span><span class="operator">::</span>toNativeSeparators(fileName)<span class="operator">,</span>
reader<span class="operator">.</span>errorString()));
} <span class="keyword">else</span> {
statusBar()<span class="operator">-</span><span class="operator">></span>showMessage(tr(<span class="string">"File loaded"</span>)<span class="operator">,</span> <span class="number">2000</span>);
}
}
</pre>
<p>The <code>saveAs()</code> function displays a <a href="../qtwidgets/qfiledialog.html">QFileDialog</a>, prompting the user for a <code>fileName</code> using <a href="../qtwidgets/qfiledialog.html#getSaveFileName">QFileDialog::getSaveFileName</a>(). Similar to the <code>open()</code> function, this function also displays a warning message if the file cannot be written to.</p>
<pre class="cpp">
<span class="type">void</span> MainWindow<span class="operator">::</span>saveAs()
{
<span class="type"><a href="../qtcore/qstring.html">QString</a></span> fileName <span class="operator">=</span>
<span class="type"><a href="../qtwidgets/qfiledialog.html">QFileDialog</a></span><span class="operator">::</span>getSaveFileName(<span class="keyword">this</span><span class="operator">,</span> tr(<span class="string">"Save Bookmark File"</span>)<span class="operator">,</span>
<span class="type"><a href="../qtcore/qdir.html">QDir</a></span><span class="operator">::</span>currentPath()<span class="operator">,</span>
tr(<span class="string">"XBEL Files (*.xbel *.xml)"</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);
<span class="keyword">if</span> (<span class="operator">!</span>file<span class="operator">.</span>open(<span class="type"><a href="../qtcore/qfile.html">QFile</a></span><span class="operator">::</span>WriteOnly <span class="operator">|</span> <span class="type"><a href="../qtcore/qfile.html">QFile</a></span><span class="operator">::</span>Text)) {
<span class="type"><a href="../qtwidgets/qmessagebox.html">QMessageBox</a></span><span class="operator">::</span>warning(<span class="keyword">this</span><span class="operator">,</span> tr(<span class="string">"QXmlStream Bookmarks"</span>)<span class="operator">,</span>
tr(<span class="string">"Cannot write file %1:\n%2."</span>)
<span class="operator">.</span>arg(<span class="type"><a href="../qtcore/qdir.html">QDir</a></span><span class="operator">::</span>toNativeSeparators(fileName)<span class="operator">,</span>
file<span class="operator">.</span>errorString()));
<span class="keyword">return</span>;
}
XbelWriter writer(treeWidget);
<span class="keyword">if</span> (writer<span class="operator">.</span>writeFile(<span class="operator">&</span>file))
statusBar()<span class="operator">-</span><span class="operator">></span>showMessage(tr(<span class="string">"File saved"</span>)<span class="operator">,</span> <span class="number">2000</span>);
}
</pre>
<p>The <code>about()</code> function displays a <a href="../qtwidgets/qmessagebox.html">QMessageBox</a> with a brief description of the example.</p>
<pre class="cpp">
<span class="type">void</span> MainWindow<span class="operator">::</span>about()
{
<span class="type"><a href="../qtwidgets/qmessagebox.html">QMessageBox</a></span><span class="operator">::</span>about(<span class="keyword">this</span><span class="operator">,</span> tr(<span class="string">"About QXmlStream Bookmarks"</span>)<span class="operator">,</span>
tr(<span class="string">"The <b>QXmlStream Bookmarks</b> example demonstrates how to use Qt's "</span>
<span class="string">"QXmlStream classes to read and write XML documents."</span>));
}
</pre>
<p>In order to implement the <code>open()</code>, <code>saveAs()</code>, <code>exit()</code>, <code>about()</code> and <code>aboutQt()</code> functions, we connect them to <a href="../qtwidgets/qaction.html">QAction</a> objects and add them to the <code>fileMenu</code> and <code>helpMenu</code>. The connections are as shown below:</p>
<pre class="cpp">
<span class="type">void</span> MainWindow<span class="operator">::</span>createMenus()
{
<span class="type"><a href="../qtwidgets/qmenu.html">QMenu</a></span> <span class="operator">*</span>fileMenu <span class="operator">=</span> menuBar()<span class="operator">-</span><span class="operator">></span>addMenu(tr(<span class="string">"&File"</span>));
<span class="type"><a href="../qtwidgets/qaction.html">QAction</a></span> <span class="operator">*</span>openAct <span class="operator">=</span> fileMenu<span class="operator">-</span><span class="operator">></span>addAction(tr(<span class="string">"&Open..."</span>)<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> <span class="operator">&</span>MainWindow<span class="operator">::</span>open);
openAct<span class="operator">-</span><span class="operator">></span>setShortcuts(<span class="type">QKeySequence</span><span class="operator">::</span>Open);
<span class="type"><a href="../qtwidgets/qaction.html">QAction</a></span> <span class="operator">*</span>saveAsAct <span class="operator">=</span> fileMenu<span class="operator">-</span><span class="operator">></span>addAction(tr(<span class="string">"&Save As..."</span>)<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> <span class="operator">&</span>MainWindow<span class="operator">::</span>saveAs);
saveAsAct<span class="operator">-</span><span class="operator">></span>setShortcuts(<span class="type">QKeySequence</span><span class="operator">::</span>SaveAs);
<span class="type"><a href="../qtwidgets/qaction.html">QAction</a></span> <span class="operator">*</span>exitAct <span class="operator">=</span> fileMenu<span class="operator">-</span><span class="operator">></span>addAction(tr(<span class="string">"E&xit"</span>)<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> <span class="operator">&</span><span class="type"><a href="../qtwidgets/qwidget.html">QWidget</a></span><span class="operator">::</span>close);
exitAct<span class="operator">-</span><span class="operator">></span>setShortcuts(<span class="type">QKeySequence</span><span class="operator">::</span>Quit);
menuBar()<span class="operator">-</span><span class="operator">></span>addSeparator();
<span class="type"><a href="../qtwidgets/qmenu.html">QMenu</a></span> <span class="operator">*</span>helpMenu <span class="operator">=</span> menuBar()<span class="operator">-</span><span class="operator">></span>addMenu(tr(<span class="string">"&Help"</span>));
helpMenu<span class="operator">-</span><span class="operator">></span>addAction(tr(<span class="string">"&About"</span>)<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> <span class="operator">&</span>MainWindow<span class="operator">::</span>about);
helpMenu<span class="operator">-</span><span class="operator">></span>addAction(tr(<span class="string">"About &Qt"</span>)<span class="operator">,</span> <a href="../qtwidgets/qapplication.html#qApp">qApp</a><span class="operator">,</span> <span class="operator">&</span><span class="type"><a href="../qtcore/qcoreapplication.html">QCoreApplication</a></span><span class="operator">::</span>quit);
}
</pre>
<p>The <code>createMenus()</code> function creates the <code>fileMenu</code> and <code>helpMenu</code> and adds the <a href="../qtwidgets/qaction.html">QAction</a> objects to them in order to create the menu shown in the screenshot below:</p>
<div class="table"><table class="generic">
<tr valign="top" class="odd"><td ><img src="images/xmlstreamexample-filemenu.png" alt="" /></td><td ><img src="images/xmlstreamexample-helpmenu.png" alt="" /></td></tr>
</table></div>
<pre class="cpp">
<span class="type">void</span> MainWindow<span class="operator">::</span>createMenus()
{
<span class="type"><a href="../qtwidgets/qmenu.html">QMenu</a></span> <span class="operator">*</span>fileMenu <span class="operator">=</span> menuBar()<span class="operator">-</span><span class="operator">></span>addMenu(tr(<span class="string">"&File"</span>));
<span class="type"><a href="../qtwidgets/qaction.html">QAction</a></span> <span class="operator">*</span>openAct <span class="operator">=</span> fileMenu<span class="operator">-</span><span class="operator">></span>addAction(tr(<span class="string">"&Open..."</span>)<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> <span class="operator">&</span>MainWindow<span class="operator">::</span>open);
openAct<span class="operator">-</span><span class="operator">></span>setShortcuts(<span class="type">QKeySequence</span><span class="operator">::</span>Open);
<span class="type"><a href="../qtwidgets/qaction.html">QAction</a></span> <span class="operator">*</span>saveAsAct <span class="operator">=</span> fileMenu<span class="operator">-</span><span class="operator">></span>addAction(tr(<span class="string">"&Save As..."</span>)<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> <span class="operator">&</span>MainWindow<span class="operator">::</span>saveAs);
saveAsAct<span class="operator">-</span><span class="operator">></span>setShortcuts(<span class="type">QKeySequence</span><span class="operator">::</span>SaveAs);
<span class="type"><a href="../qtwidgets/qaction.html">QAction</a></span> <span class="operator">*</span>exitAct <span class="operator">=</span> fileMenu<span class="operator">-</span><span class="operator">></span>addAction(tr(<span class="string">"E&xit"</span>)<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> <span class="operator">&</span><span class="type"><a href="../qtwidgets/qwidget.html">QWidget</a></span><span class="operator">::</span>close);
exitAct<span class="operator">-</span><span class="operator">></span>setShortcuts(<span class="type">QKeySequence</span><span class="operator">::</span>Quit);
menuBar()<span class="operator">-</span><span class="operator">></span>addSeparator();
<span class="type"><a href="../qtwidgets/qmenu.html">QMenu</a></span> <span class="operator">*</span>helpMenu <span class="operator">=</span> menuBar()<span class="operator">-</span><span class="operator">></span>addMenu(tr(<span class="string">"&Help"</span>));
helpMenu<span class="operator">-</span><span class="operator">></span>addAction(tr(<span class="string">"&About"</span>)<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> <span class="operator">&</span>MainWindow<span class="operator">::</span>about);
helpMenu<span class="operator">-</span><span class="operator">></span>addAction(tr(<span class="string">"About &Qt"</span>)<span class="operator">,</span> <a href="../qtwidgets/qapplication.html#qApp">qApp</a><span class="operator">,</span> <span class="operator">&</span><span class="type"><a href="../qtcore/qcoreapplication.html">QCoreApplication</a></span><span class="operator">::</span>quit);
}
</pre>
<a name="main-function"></a>
<h2 id="main-function"><code>main()</code> Function</h2>
<p>The <code>main()</code> function instantiates <code>MainWindow</code> and invokes the <code>show()</code> function.</p>
<pre class="cpp">
<span class="type">int</span> main(<span class="type">int</span> argc<span class="operator">,</span> <span class="type">char</span> <span class="operator">*</span>argv<span class="operator">[</span><span class="operator">]</span>)
{
<span class="type"><a href="../qtwidgets/qapplication.html">QApplication</a></span> app(argc<span class="operator">,</span> argv);
MainWindow mainWin;
mainWin<span class="operator">.</span>show();
mainWin<span class="operator">.</span>open();
<span class="keyword">return</span> app<span class="operator">.</span>exec();
}
</pre>
<p>See the <a href="http://pyxml.sourceforge.net/topics/xbel/">XML Bookmark Exchange Language Resource Page</a> for more information about XBEL files.</p>
<p>Files:</p>
<ul>
<li><a href="qtxml-streambookmarks-main-cpp.html">streambookmarks/main.cpp</a></li>
<li><a href="qtxml-streambookmarks-mainwindow-cpp.html">streambookmarks/mainwindow.cpp</a></li>
<li><a href="qtxml-streambookmarks-mainwindow-h.html">streambookmarks/mainwindow.h</a></li>
<li><a href="qtxml-streambookmarks-streambookmarks-pro.html">streambookmarks/streambookmarks.pro</a></li>
<li><a href="qtxml-streambookmarks-xbelreader-cpp.html">streambookmarks/xbelreader.cpp</a></li>
<li><a href="qtxml-streambookmarks-xbelreader-h.html">streambookmarks/xbelreader.h</a></li>
<li><a href="qtxml-streambookmarks-xbelwriter-cpp.html">streambookmarks/xbelwriter.cpp</a></li>
<li><a href="qtxml-streambookmarks-xbelwriter-h.html">streambookmarks/xbelwriter.h</a></li>
</ul>
</div>
<!-- @@@streambookmarks -->
</div>
</div>
</div>
</div>
</div>
<div class="footer">
<p>
<acronym title="Copyright">©</acronym> 2019 The Qt Company Ltd.
Documentation contributions included herein are the copyrights of
their respective owners.<br/> The documentation provided herein is licensed under the terms of the <a href="http://www.gnu.org/licenses/fdl.html">GNU Free Documentation License version 1.3</a> as published by the Free Software Foundation.<br/> Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property
of their respective owners. </p>
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distrib
>
Mageia
>
7
>
armv7hl
>
media
>
core-updates
>
by-pkgid
>
d5e62c01ae8d1e579463c6a871dd44bf
>
files
>
5318
