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<td >Qt 5.9</td><td ><a href="qtwidgets-index.html">Qt Widgets</a></td><td >Drop Site Example</td></tr></table><table class="buildversion"><tr>
<td id="buildversion" width="100%" align="right">Qt 5.9.4 Reference Documentation</td>
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<h3><a name="toc">Contents</a></h3>
<ul>
<li class="level1"><a href="#droparea-class-definition">DropArea Class Definition</a></li>
<li class="level1"><a href="#droparea-class-implementation">DropArea Class Implementation</a></li>
<li class="level1"><a href="#dropsitewindow-class-definition">DropSiteWindow Class Definition</a></li>
<li class="level1"><a href="#dropsitewindow-class-implementation">DropSiteWindow Class Implementation</a></li>
<li class="level1"><a href="#the-main-function">The main() Function</a></li>
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<h1 class="title">Drop Site Example</h1>
<span class="subtitle"></span>
<!-- $$$draganddrop/dropsite-description -->
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<p class="centerAlign"><img src="images/dropsite-example.png" alt="Screenshot of the Drop Site example" /></p><p>The Drop Site example accepts drops from other applications, and displays the MIME formats provided by the drag object.</p>
<p>There are two classes, <code>DropArea</code> and <code>DropSiteWindow</code>, and a <code>main()</code> function in this example. A <code>DropArea</code> object is instantiated in <code>DropSiteWindow</code>; a <code>DropSiteWindow</code> object is then invoked in the <code>main()</code> function.</p>
<a name="droparea-class-definition"></a>
<h2 id="droparea-class-definition">DropArea Class Definition</h2>
<p>The <code>DropArea</code> class is a subclass of <a href="qlabel.html">QLabel</a> with a public slot, <code>clear()</code>, and a <code>changed()</code> signal.</p>
<pre class="cpp">
<span class="keyword">class</span> DropArea : <span class="keyword">public</span> <span class="type"><a href="qlabel.html">QLabel</a></span>
{
Q_OBJECT
<span class="keyword">public</span>:
DropArea(<span class="type"><a href="qwidget.html">QWidget</a></span> <span class="operator">*</span>parent <span class="operator">=</span> <span class="number">0</span>);
<span class="keyword">public</span> <span class="keyword">slots</span>:
<span class="type">void</span> clear();
<span class="keyword">signals</span>:
<span class="type">void</span> changed(<span class="keyword">const</span> <span class="type"><a href="../qtcore/qmimedata.html">QMimeData</a></span> <span class="operator">*</span>mimeData <span class="operator">=</span> <span class="number">0</span>);
</pre>
<p>In addition, <code>DropArea</code> also contains a private instance of <a href="qlabel.html">QLabel</a> and reimplementations of four <a href="qwidget.html">QWidget</a> event handlers:</p>
<ol class="1" type="1"><li><a href="qwidget.html#dragEnterEvent">dragEnterEvent()</a></li>
<li><a href="qwidget.html#dragMoveEvent">dragMoveEvent()</a></li>
<li><a href="qwidget.html#dragLeaveEvent">dragLeaveEvent()</a></li>
<li><a href="qwidget.html#dropEvent">dropEvent()</a></li>
</ol>
<p>These event handlers are further explained in the implementation of the <code>DropArea</code> class.</p>
<pre class="cpp">
<span class="keyword">protected</span>:
<span class="type">void</span> dragEnterEvent(<span class="type"><a href="../qtgui/qdragenterevent.html">QDragEnterEvent</a></span> <span class="operator">*</span>event) override;
<span class="type">void</span> dragMoveEvent(<span class="type"><a href="../qtgui/qdragmoveevent.html">QDragMoveEvent</a></span> <span class="operator">*</span>event) override;
<span class="type">void</span> dragLeaveEvent(<span class="type"><a href="../qtgui/qdragleaveevent.html">QDragLeaveEvent</a></span> <span class="operator">*</span>event) override;
<span class="type">void</span> dropEvent(<span class="type"><a href="../qtgui/qdropevent.html">QDropEvent</a></span> <span class="operator">*</span>event) override;
<span class="keyword">private</span>:
<span class="type"><a href="qlabel.html">QLabel</a></span> <span class="operator">*</span>label;
};
</pre>
<a name="droparea-class-implementation"></a>
<h2 id="droparea-class-implementation">DropArea Class Implementation</h2>
<p>In the <code>DropArea</code> constructor, we set the <a href="qwidget.html#minimumSize-prop">minimum size</a> to 200x200 pixels, the <a href="qframe.html#setFrameStyle">frame style</a> to both <a href="qframe.html#Shadow-enum">QFrame::Sunken</a> and <a href="qframe.html#Shape-enum">QFrame::StyledPanel</a>, and we align its contents to the center.</p>
<pre class="cpp">
DropArea<span class="operator">::</span>DropArea(<span class="type"><a href="qwidget.html">QWidget</a></span> <span class="operator">*</span>parent)
: <span class="type"><a href="qlabel.html">QLabel</a></span>(parent)
{
setMinimumSize(<span class="number">200</span><span class="operator">,</span> <span class="number">200</span>);
setFrameStyle(<span class="type"><a href="qframe.html">QFrame</a></span><span class="operator">::</span>Sunken <span class="operator">|</span> <span class="type"><a href="qframe.html">QFrame</a></span><span class="operator">::</span>StyledPanel);
setAlignment(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>AlignCenter);
setAcceptDrops(<span class="keyword">true</span>);
setAutoFillBackground(<span class="keyword">true</span>);
clear();
}
</pre>
<p>Also, we enable drop events in <code>DropArea</code> by setting the <a href="qwidget.html#acceptDrops-prop">acceptDrops</a> property to <code>true</code>. Then, we enable the <a href="qwidget.html#autoFillBackground-prop">autoFillBackground</a> property and invoke the <code>clear()</code> function.</p>
<p>The <a href="qwidget.html#dragEnterEvent">dragEnterEvent()</a> event handler is called when a drag is in progress and the mouse enters the <code>DropArea</code> object. For the <code>DropSite</code> example, when the mouse enters <code>DropArea</code>, we set its text to "<drop content>" and highlight its background.</p>
<pre class="cpp">
<span class="type">void</span> DropArea<span class="operator">::</span>dragEnterEvent(<span class="type"><a href="../qtgui/qdragenterevent.html">QDragEnterEvent</a></span> <span class="operator">*</span>event)
{
setText(tr(<span class="string">"<drop content>"</span>));
setBackgroundRole(<span class="type"><a href="../qtgui/qpalette.html">QPalette</a></span><span class="operator">::</span>Highlight);
event<span class="operator">-</span><span class="operator">></span>acceptProposedAction();
<span class="keyword">emit</span> changed(event<span class="operator">-</span><span class="operator">></span>mimeData());
}
</pre>
<p>Then, we invoke <a href="../qtgui/qdropevent.html#acceptProposedAction">acceptProposedAction()</a> on <i>event</i>, setting the drop action to the one proposed. Lastly, we emit the <code>changed()</code> signal, with the data that was dropped and its MIME type information as a parameter.</p>
<p>For <a href="qwidget.html#dragMoveEvent">dragMoveEvent()</a>, we just accept the proposed <a href="../qtgui/qdragmoveevent.html">QDragMoveEvent</a> object, <i>event</i>, with <a href="../qtgui/qdropevent.html#acceptProposedAction">acceptProposedAction()</a>.</p>
<pre class="cpp">
<span class="type">void</span> DropArea<span class="operator">::</span>dragMoveEvent(<span class="type"><a href="../qtgui/qdragmoveevent.html">QDragMoveEvent</a></span> <span class="operator">*</span>event)
{
event<span class="operator">-</span><span class="operator">></span>acceptProposedAction();
}
</pre>
<p>The <code>DropArea</code> class's implementation of <a href="qwidget.html#dropEvent">dropEvent()</a> extracts the <i>event</i>'s mime data and displays it accordingly.</p>
<pre class="cpp">
<span class="type">void</span> DropArea<span class="operator">::</span>dropEvent(<span class="type"><a href="../qtgui/qdropevent.html">QDropEvent</a></span> <span class="operator">*</span>event)
{
<span class="keyword">const</span> <span class="type"><a href="../qtcore/qmimedata.html">QMimeData</a></span> <span class="operator">*</span>mimeData <span class="operator">=</span> event<span class="operator">-</span><span class="operator">></span>mimeData();
</pre>
<p>The <code>mimeData</code> object can contain one of the following objects: an image, HTML text, plain text, or a list of URLs.</p>
<pre class="cpp">
<span class="keyword">if</span> (mimeData<span class="operator">-</span><span class="operator">></span>hasImage()) {
setPixmap(qvariant_cast<span class="operator"><</span><span class="type"><a href="../qtgui/qpixmap.html">QPixmap</a></span><span class="operator">></span>(mimeData<span class="operator">-</span><span class="operator">></span>imageData()));
} <span class="keyword">else</span> <span class="keyword">if</span> (mimeData<span class="operator">-</span><span class="operator">></span>hasHtml()) {
setText(mimeData<span class="operator">-</span><span class="operator">></span>html());
setTextFormat(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>RichText);
} <span class="keyword">else</span> <span class="keyword">if</span> (mimeData<span class="operator">-</span><span class="operator">></span>hasText()) {
setText(mimeData<span class="operator">-</span><span class="operator">></span>text());
setTextFormat(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>PlainText);
} <span class="keyword">else</span> <span class="keyword">if</span> (mimeData<span class="operator">-</span><span class="operator">></span>hasUrls()) {
<span class="type"><a href="../qtcore/qlist.html">QList</a></span><span class="operator"><</span><span class="type"><a href="../qtcore/qurl.html">QUrl</a></span><span class="operator">></span> urlList <span class="operator">=</span> mimeData<span class="operator">-</span><span class="operator">></span>urls();
<span class="type"><a href="../qtcore/qstring.html">QString</a></span> text;
<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> urlList<span class="operator">.</span>size() <span class="operator">&</span><span class="operator">&</span> i <span class="operator"><</span> <span class="number">32</span>; <span class="operator">+</span><span class="operator">+</span>i)
text <span class="operator">+</span><span class="operator">=</span> urlList<span class="operator">.</span>at(i)<span class="operator">.</span>path() <span class="operator">+</span> QLatin1Char(<span class="char">'\n'</span>);
setText(text);
} <span class="keyword">else</span> {
setText(tr(<span class="string">"Cannot display data"</span>));
}
</pre>
<ul>
<li>If <code>mimeData</code> contains an image, we display it in <code>DropArea</code> with <a href="qlabel.html#pixmap-prop">setPixmap()</a>.</li>
<li>If <code>mimeData</code> contains HTML, we display it with <a href="qlabel.html#text-prop">setText()</a> and set <code>DropArea</code>'s text format as <a href="../qtcore/qt.html#TextFormat-enum">Qt::RichText</a>.</li>
<li>If <code>mimeData</code> contains plain text, we display it with <a href="qlabel.html#text-prop">setText()</a> and set <code>DropArea</code>'s text format as <a href="../qtcore/qt.html#TextFormat-enum">Qt::PlainText</a>. In the event that <code>mimeData</code> contains URLs, we iterate through the list of URLs to display them on individual lines.</li>
<li>If <code>mimeData</code> contains other types of objects, we set <code>DropArea</code>'s text, with <a href="qlabel.html#text-prop">setText()</a> to "Cannot display data" to inform the user.</li>
</ul>
<p>We then set <code>DropArea</code>'s <a href="qwidget.html#backgroundRole">backgroundRole</a> to <a href="../qtgui/qpalette.html#ColorRole-enum">QPalette::Dark</a> and we accept <code>event</code>'s proposed action.</p>
<pre class="cpp">
setBackgroundRole(<span class="type"><a href="../qtgui/qpalette.html">QPalette</a></span><span class="operator">::</span>Dark);
event<span class="operator">-</span><span class="operator">></span>acceptProposedAction();
}
</pre>
<p>The <a href="qwidget.html#dragLeaveEvent">dragLeaveEvent()</a> event handler is called when a drag is in progress and the mouse leaves the widget.</p>
<pre class="cpp">
<span class="type">void</span> DropArea<span class="operator">::</span>dragLeaveEvent(<span class="type"><a href="../qtgui/qdragleaveevent.html">QDragLeaveEvent</a></span> <span class="operator">*</span>event)
{
clear();
event<span class="operator">-</span><span class="operator">></span>accept();
}
</pre>
<p>For <code>DropArea</code>'s implementation, we clear invoke <code>clear()</code> and then accept the proposed event.</p>
<p>The <code>clear()</code> function sets the text in <code>DropArea</code> to "<drop content>" and sets the <a href="qwidget.html#backgroundRole">backgroundRole</a> to <a href="../qtgui/qpalette.html#ColorRole-enum">QPalette::Dark</a>. Lastly, it emits the <code>changed()</code> signal.</p>
<pre class="cpp">
<span class="type">void</span> DropArea<span class="operator">::</span>clear()
{
setText(tr(<span class="string">"<drop content>"</span>));
setBackgroundRole(<span class="type"><a href="../qtgui/qpalette.html">QPalette</a></span><span class="operator">::</span>Dark);
<span class="keyword">emit</span> changed();
}
</pre>
<a name="dropsitewindow-class-definition"></a>
<h2 id="dropsitewindow-class-definition">DropSiteWindow Class Definition</h2>
<p>The <code>DropSiteWindow</code> class contains a constructor and a public slot, <code>updateFormatsTable()</code>.</p>
<pre class="cpp">
<span class="keyword">class</span> DropSiteWindow : <span class="keyword">public</span> <span class="type"><a href="qwidget.html">QWidget</a></span>
{
Q_OBJECT
<span class="keyword">public</span>:
DropSiteWindow();
<span class="keyword">public</span> <span class="keyword">slots</span>:
<span class="type">void</span> updateFormatsTable(<span class="keyword">const</span> <span class="type"><a href="../qtcore/qmimedata.html">QMimeData</a></span> <span class="operator">*</span>mimeData);
<span class="keyword">private</span>:
DropArea <span class="operator">*</span>dropArea;
<span class="type"><a href="qlabel.html">QLabel</a></span> <span class="operator">*</span>abstractLabel;
<span class="type"><a href="qtablewidget.html">QTableWidget</a></span> <span class="operator">*</span>formatsTable;
<span class="type"><a href="qpushbutton.html">QPushButton</a></span> <span class="operator">*</span>clearButton;
<span class="type"><a href="qpushbutton.html">QPushButton</a></span> <span class="operator">*</span>quitButton;
<span class="type"><a href="qdialogbuttonbox.html">QDialogButtonBox</a></span> <span class="operator">*</span>buttonBox;
};
</pre>
<p>The class also contains a private instance of <code>DropArea</code>, <code>dropArea</code>, <a href="qlabel.html">QLabel</a>, <code>abstractLabel</code>, <a href="qtablewidget.html">QTableWidget</a>, <code>formatsTable</code>, <a href="qdialogbuttonbox.html">QDialogButtonBox</a>, <code>buttonBox</code>, and two <a href="qpushbutton.html">QPushButton</a> objects, <code>clearButton</code> and <code>quitButton</code>.</p>
<a name="dropsitewindow-class-implementation"></a>
<h2 id="dropsitewindow-class-implementation">DropSiteWindow Class Implementation</h2>
<p>In the constructor of <code>DropSiteWindow</code>, we instantiate <code>abstractLabel</code> and set its <a href="qlabel.html#wordWrap-prop">wordWrap</a> property to <code>true</code>. We also call the <a href="qwidget.html#adjustSize">adjustSize()</a> function to adjust <code>abstractLabel</code>'s size according to its contents.</p>
<pre class="cpp">
DropSiteWindow<span class="operator">::</span>DropSiteWindow()
{
abstractLabel <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qlabel.html">QLabel</a></span>(tr(<span class="string">"This example accepts drags from other "</span>
<span class="string">"applications and displays the MIME types "</span>
<span class="string">"provided by the drag object."</span>));
abstractLabel<span class="operator">-</span><span class="operator">></span>setWordWrap(<span class="keyword">true</span>);
abstractLabel<span class="operator">-</span><span class="operator">></span>adjustSize();
</pre>
<p>Then we instantiate <code>dropArea</code> and connect its <code>changed()</code> signal to <code>DropSiteWindow</code>'s <code>updateFormatsTable()</code> slot.</p>
<pre class="cpp">
dropArea <span class="operator">=</span> <span class="keyword">new</span> DropArea;
connect(dropArea<span class="operator">,</span> <span class="operator">&</span>DropArea<span class="operator">::</span>changed<span class="operator">,</span>
<span class="keyword">this</span><span class="operator">,</span> <span class="operator">&</span>DropSiteWindow<span class="operator">::</span>updateFormatsTable);
</pre>
<p>We now set up the <a href="qtablewidget.html">QTableWidget</a> object, <code>formatsTable</code>. Its horizontal header is set using a <a href="../qtcore/qstringlist.html">QStringList</a> object, <code>labels</code>. The number of columms are set to two and the table is not editable. Also, the <code>formatTable</code>'s horizontal header is formatted to ensure that its second column stretches to occupy additional space available.</p>
<pre class="cpp">
<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">"Format"</span>) <span class="operator"><</span><span class="operator"><</span> tr(<span class="string">"Content"</span>);
formatsTable <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qtablewidget.html">QTableWidget</a></span>;
formatsTable<span class="operator">-</span><span class="operator">></span>setColumnCount(<span class="number">2</span>);
formatsTable<span class="operator">-</span><span class="operator">></span>setEditTriggers(<span class="type"><a href="qabstractitemview.html">QAbstractItemView</a></span><span class="operator">::</span>NoEditTriggers);
formatsTable<span class="operator">-</span><span class="operator">></span>setHorizontalHeaderLabels(labels);
formatsTable<span class="operator">-</span><span class="operator">></span>horizontalHeader()<span class="operator">-</span><span class="operator">></span>setStretchLastSection(<span class="keyword">true</span>);
</pre>
<p>Two <a href="qpushbutton.html">QPushButton</a> objects, <code>clearButton</code> and <code>quitButton</code>, are instantiated and added to <code>buttonBox</code> - a <a href="qdialogbuttonbox.html">QDialogButtonBox</a> object. We use <a href="qdialogbuttonbox.html">QDialogButtonBox</a> here to ensure that the push buttons are presented in a layout that conforms to the platform's style.</p>
<pre class="cpp">
clearButton <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qpushbutton.html">QPushButton</a></span>(tr(<span class="string">"Clear"</span>));
quitButton <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qpushbutton.html">QPushButton</a></span>(tr(<span class="string">"Quit"</span>));
buttonBox <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qdialogbuttonbox.html">QDialogButtonBox</a></span>;
buttonBox<span class="operator">-</span><span class="operator">></span>addButton(clearButton<span class="operator">,</span> <span class="type"><a href="qdialogbuttonbox.html">QDialogButtonBox</a></span><span class="operator">::</span>ActionRole);
buttonBox<span class="operator">-</span><span class="operator">></span>addButton(quitButton<span class="operator">,</span> <span class="type"><a href="qdialogbuttonbox.html">QDialogButtonBox</a></span><span class="operator">::</span>RejectRole);
connect(quitButton<span class="operator">,</span> <span class="operator">&</span><span class="type"><a href="qabstractbutton.html">QAbstractButton</a></span><span class="operator">::</span>pressed<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> <span class="operator">&</span><span class="type"><a href="qwidget.html">QWidget</a></span><span class="operator">::</span>close);
connect(clearButton<span class="operator">,</span> <span class="operator">&</span><span class="type"><a href="qabstractbutton.html">QAbstractButton</a></span><span class="operator">::</span>pressed<span class="operator">,</span> dropArea<span class="operator">,</span> <span class="operator">&</span>DropArea<span class="operator">::</span>clear);
</pre>
<p>The <a href="qabstractbutton.html#clicked">clicked()</a> signals for <code>quitButton</code> and <code>clearButton</code> are connected to <a href="qwidget.html#close">close()</a> and <code>clear()</code>, respectively.</p>
<p>For the layout, we use a <a href="qvboxlayout.html">QVBoxLayout</a>, <code>mainLayout</code>, to arrange our widgets vertically. We also set the window title to "Drop Site" and the minimum size to 350x500 pixels.</p>
<pre class="cpp">
<span class="type"><a href="qvboxlayout.html">QVBoxLayout</a></span> <span class="operator">*</span>mainLayout <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qvboxlayout.html">QVBoxLayout</a></span>(<span class="keyword">this</span>);
mainLayout<span class="operator">-</span><span class="operator">></span>addWidget(abstractLabel);
mainLayout<span class="operator">-</span><span class="operator">></span>addWidget(dropArea);
mainLayout<span class="operator">-</span><span class="operator">></span>addWidget(formatsTable);
mainLayout<span class="operator">-</span><span class="operator">></span>addWidget(buttonBox);
setWindowTitle(tr(<span class="string">"Drop Site"</span>));
setMinimumSize(<span class="number">350</span><span class="operator">,</span> <span class="number">500</span>);
}
</pre>
<p>We move on to the <code>updateFormatsTable()</code> function. This function updates the <code>formatsTable</code>, displaying the MIME formats of the object dropped onto the <code>DropArea</code> object. First, we set <a href="qtablewidget.html">QTableWidget</a>'s <a href="qtablewidget.html#setRowCount">rowCount</a> property to 0. Then, we validate to ensure that the <a href="../qtcore/qmimedata.html">QMimeData</a> object passed in is a valid object.</p>
<pre class="cpp">
<span class="type">void</span> DropSiteWindow<span class="operator">::</span>updateFormatsTable(<span class="keyword">const</span> <span class="type"><a href="../qtcore/qmimedata.html">QMimeData</a></span> <span class="operator">*</span>mimeData)
{
formatsTable<span class="operator">-</span><span class="operator">></span>setRowCount(<span class="number">0</span>);
<span class="keyword">if</span> (<span class="operator">!</span>mimeData)
<span class="keyword">return</span>;
</pre>
<p>Once we are sure that <code>mimeData</code> is valid, we iterate through its supported formats using the <a href="../qtcore/containers.html#the-foreach-keyword">foreach keyword</a>. This keyword has the following format:</p>
<pre class="cpp">
foreach(variable<span class="operator">,</span> container)
</pre>
<p>In our example, <code>format</code> is the <i>variable</i> and the <i>container</i> is a <a href="../qtcore/qstringlist.html">QStringList</a>, obtained from <code>mimeData->formats()</code>.</p>
<p><b>Note: </b>The <a href="../qtcore/qmimedata.html#formats">formats()</a> function returns a <a href="../qtcore/qstringlist.html">QStringList</a> object, containing all the formats supported by the <code>mimeData</code>.</p><pre class="cpp">
foreach (<span class="type"><a href="../qtcore/qstring.html">QString</a></span> format<span class="operator">,</span> mimeData<span class="operator">-</span><span class="operator">></span>formats()) {
<span class="type"><a href="qtablewidgetitem.html">QTableWidgetItem</a></span> <span class="operator">*</span>formatItem <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qtablewidgetitem.html">QTableWidgetItem</a></span>(format);
formatItem<span class="operator">-</span><span class="operator">></span>setFlags(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>ItemIsEnabled);
formatItem<span class="operator">-</span><span class="operator">></span>setTextAlignment(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>AlignTop <span class="operator">|</span> <span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>AlignLeft);
</pre>
<p>Within each iteration, we create a <a href="qtablewidgetitem.html">QTableWidgetItem</a>, <code>formatItem</code> and we set its <a href="qtablewidgetitem.html#setFlags">flags</a> to <a href="../qtcore/qt.html#ItemFlag-enum">Qt::ItemIsEnabled</a>, and its <a href="qtablewidgetitem.html#setTextAlignment">text alignment</a> to <a href="../qtcore/qt.html#AlignmentFlag-enum">Qt::AlignTop</a> and <a href="../qtcore/qt.html#AlignmentFlag-enum">Qt::AlignLeft</a>.</p>
<p>A <a href="../qtcore/qstring.html">QString</a> object, <code>text</code>, is customized to display data according to the contents of <code>format</code>. We invoke <a href="../qtcore/qstring.html">QString</a>'s <a href="../qtcore/qstring.html#simplified">simplified()</a> function on <code>text</code>, to obtain a string that has no additional space before, after or in between words.</p>
<pre class="cpp">
<span class="type"><a href="../qtcore/qstring.html">QString</a></span> text;
<span class="keyword">if</span> (format <span class="operator">=</span><span class="operator">=</span> QLatin1String(<span class="string">"text/plain"</span>)) {
text <span class="operator">=</span> mimeData<span class="operator">-</span><span class="operator">></span>text()<span class="operator">.</span>simplified();
} <span class="keyword">else</span> <span class="keyword">if</span> (format <span class="operator">=</span><span class="operator">=</span> QLatin1String(<span class="string">"text/html"</span>)) {
text <span class="operator">=</span> mimeData<span class="operator">-</span><span class="operator">></span>html()<span class="operator">.</span>simplified();
} <span class="keyword">else</span> <span class="keyword">if</span> (format <span class="operator">=</span><span class="operator">=</span> QLatin1String(<span class="string">"text/uri-list"</span>)) {
<span class="type"><a href="../qtcore/qlist.html">QList</a></span><span class="operator"><</span><span class="type"><a href="../qtcore/qurl.html">QUrl</a></span><span class="operator">></span> urlList <span class="operator">=</span> mimeData<span class="operator">-</span><span class="operator">></span>urls();
<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> urlList<span class="operator">.</span>size() <span class="operator">&</span><span class="operator">&</span> i <span class="operator"><</span> <span class="number">32</span>; <span class="operator">+</span><span class="operator">+</span>i)
text<span class="operator">.</span>append(urlList<span class="operator">.</span>at(i)<span class="operator">.</span>toString() <span class="operator">+</span> QLatin1Char(<span class="char">' '</span>));
} <span class="keyword">else</span> {
<span class="type"><a href="../qtcore/qbytearray.html">QByteArray</a></span> data <span class="operator">=</span> mimeData<span class="operator">-</span><span class="operator">></span>data(format);
<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> data<span class="operator">.</span>size() <span class="operator">&</span><span class="operator">&</span> i <span class="operator"><</span> <span class="number">32</span>; <span class="operator">+</span><span class="operator">+</span>i)
text<span class="operator">.</span>append(<span class="type"><a href="../qtcore/qstring.html#QStringLiteral">QStringLiteral</a></span>(<span class="string">"%1 "</span>)<span class="operator">.</span>arg(<span class="type"><a href="../qtcore/qtglobal.html#uchar-typedef">uchar</a></span>(data<span class="operator">[</span>i<span class="operator">]</span>)<span class="operator">,</span> <span class="number">2</span><span class="operator">,</span> <span class="number">16</span><span class="operator">,</span> QLatin1Char(<span class="char">'0'</span>))<span class="operator">.</span>toUpper());
}
</pre>
<p>If <code>format</code> contains a list of URLs, we iterate through them, using spaces to separate them. On the other hand, if <code>format</code> contains an image, we display the data by converting the text to hexadecimal.</p>
<pre class="cpp">
<span class="type">int</span> row <span class="operator">=</span> formatsTable<span class="operator">-</span><span class="operator">></span>rowCount();
formatsTable<span class="operator">-</span><span class="operator">></span>insertRow(row);
formatsTable<span class="operator">-</span><span class="operator">></span>setItem(row<span class="operator">,</span> <span class="number">0</span><span class="operator">,</span> <span class="keyword">new</span> <span class="type"><a href="qtablewidgetitem.html">QTableWidgetItem</a></span>(format));
formatsTable<span class="operator">-</span><span class="operator">></span>setItem(row<span class="operator">,</span> <span class="number">1</span><span class="operator">,</span> <span class="keyword">new</span> <span class="type"><a href="qtablewidgetitem.html">QTableWidgetItem</a></span>(text));
}
formatsTable<span class="operator">-</span><span class="operator">></span>resizeColumnToContents(<span class="number">0</span>);
}
</pre>
<p>Once <code>text</code> has been customized to contain the appropriate data, we insert both <code>format</code> and <code>text</code> into <code>formatsTable</code> with <a href="qtablewidget.html#setItem">setItem()</a>. Lastly, we invoke <a href="qtableview.html#resizeColumnToContents">resizeColumnToContents()</a> on <code>formatsTable</code>'s first column.</p>
<a name="the-main-function"></a>
<h2 id="the-main-function">The main() Function</h2>
<p>Within the <code>main()</code> function, we instantiate <code>DropSiteWindow</code> and invoke its <a href="qwidget.html#show">show()</a> 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="qapplication.html">QApplication</a></span> app(argc<span class="operator">,</span> argv);
DropSiteWindow window;
window<span class="operator">.</span>show();
<span class="keyword">return</span> app<span class="operator">.</span>exec();
}
</pre>
<p>Files:</p>
<ul>
<li><a href="qtwidgets-draganddrop-dropsite-droparea-cpp.html">draganddrop/dropsite/droparea.cpp</a></li>
<li><a href="qtwidgets-draganddrop-dropsite-droparea-h.html">draganddrop/dropsite/droparea.h</a></li>
<li><a href="qtwidgets-draganddrop-dropsite-dropsitewindow-cpp.html">draganddrop/dropsite/dropsitewindow.cpp</a></li>
<li><a href="qtwidgets-draganddrop-dropsite-dropsitewindow-h.html">draganddrop/dropsite/dropsitewindow.h</a></li>
<li><a href="qtwidgets-draganddrop-dropsite-main-cpp.html">draganddrop/dropsite/main.cpp</a></li>
<li><a href="qtwidgets-draganddrop-dropsite-dropsite-pro.html">draganddrop/dropsite/dropsite.pro</a></li>
</ul>
</div>
<!-- @@@draganddrop/dropsite -->
</div>
</div>
</div>
</div>
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<p>
<acronym title="Copyright">©</acronym> 2017 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
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distrib
>
Mageia
>
6
>
armv5tl
>
media
>
core-updates
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by-pkgid
>
768f7d9f703884aa2562bf0a651086df
>
files
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3784
