<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE html> <html lang="en"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>dragwidget.cpp Example File | Qt Widgets 5.12.6</title> <link rel="stylesheet" type="text/css" href="style/offline-simple.css" /> <script type="text/javascript"> document.getElementsByTagName("link").item(0).setAttribute("href", "style/offline.css"); // loading style sheet breaks anchors that were jumped to before // so force jumping to anchor again setTimeout(function() { var anchor = location.hash; // need to jump to different anchor first (e.g. none) location.hash = "#"; setTimeout(function() { location.hash = anchor; }, 0); }, 0); </script> </head> <body> <div class="header" id="qtdocheader"> <div class="main"> <div class="main-rounded"> <div class="navigationbar"> <table><tr> <td >Qt 5.12</td><td ><a href="qtwidgets-index.html">Qt Widgets</a></td><td ><a href="qtwidgets-draganddrop-fridgemagnets-example.html">Fridge Magnets Example</a></td><td >dragwidget.cpp Example File</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> </tr></table> </div> </div> <div class="content"> <div class="line"> <div class="content mainContent"> <div class="sidebar"><div class="sidebar-content" id="sidebar-content"></div></div> <h1 class="title">dragwidget.cpp Example File</h1> <span class="subtitle">draganddrop/fridgemagnets/dragwidget.cpp</span> <!-- $$$draganddrop/fridgemagnets/dragwidget.cpp-description --> <div class="descr"> <a name="details"></a> <pre class="cpp"> <span class="comment">/**************************************************************************** ** ** Copyright (C) 2016 The Qt Company Ltd. ** Contact: https://www.qt.io/licensing/ ** ** This file is part of the examples of the Qt Toolkit. ** ** $QT_BEGIN_LICENSE:BSD$ ** Commercial License Usage ** Licensees holding valid commercial Qt licenses may use this file in ** accordance with the commercial license agreement provided with the ** Software or, alternatively, in accordance with the terms contained in ** a written agreement between you and The Qt Company. For licensing terms ** and conditions see https://www.qt.io/terms-conditions. For further ** information use the contact form at https://www.qt.io/contact-us. ** ** BSD License Usage ** Alternatively, you may use this file under the terms of the BSD license ** as follows: ** ** "Redistribution and use in source and binary forms, with or without ** modification, are permitted provided that the following conditions are ** met: ** * Redistributions of source code must retain the above copyright ** notice, this list of conditions and the following disclaimer. ** * Redistributions in binary form must reproduce the above copyright ** notice, this list of conditions and the following disclaimer in ** the documentation and/or other materials provided with the ** distribution. ** * Neither the name of The Qt Company Ltd nor the names of its ** contributors may be used to endorse or promote products derived ** from this software without specific prior written permission. ** ** ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE." ** ** $QT_END_LICENSE$ ** ****************************************************************************/</span> <span class="preprocessor">#include "draglabel.h"</span> <span class="preprocessor">#include "dragwidget.h"</span> <span class="preprocessor">#include <QtWidgets></span> <span class="keyword">static</span> <span class="keyword">inline</span> <span class="type"><a href="../qtcore/qstring.html">QString</a></span> fridgetMagnetsMimeType() { <span class="keyword">return</span> <span class="type"><a href="../qtcore/qstring.html#QStringLiteral">QStringLiteral</a></span>(<span class="string">"application/x-fridgemagnet"</span>); } DragWidget<span class="operator">::</span>DragWidget(<span class="type"><a href="qwidget.html">QWidget</a></span> <span class="operator">*</span>parent) : <span class="type"><a href="qwidget.html">QWidget</a></span>(parent) { <span class="type"><a href="../qtcore/qfile.html">QFile</a></span> dictionaryFile(<span class="type"><a href="../qtcore/qstring.html#QStringLiteral">QStringLiteral</a></span>(<span class="string">":/dictionary/words.txt"</span>)); dictionaryFile<span class="operator">.</span>open(<span class="type"><a href="../qtcore/qfile.html">QFile</a></span><span class="operator">::</span>ReadOnly); <span class="type"><a href="../qtcore/qtextstream.html">QTextStream</a></span> inputStream(<span class="operator">&</span>dictionaryFile); <span class="type">int</span> x <span class="operator">=</span> <span class="number">5</span>; <span class="type">int</span> y <span class="operator">=</span> <span class="number">5</span>; <span class="keyword">while</span> (<span class="operator">!</span>inputStream<span class="operator">.</span>atEnd()) { <span class="type"><a href="../qtcore/qstring.html">QString</a></span> word; inputStream <span class="operator">></span><span class="operator">></span> word; <span class="keyword">if</span> (<span class="operator">!</span>word<span class="operator">.</span>isEmpty()) { DragLabel <span class="operator">*</span>wordLabel <span class="operator">=</span> <span class="keyword">new</span> DragLabel(word<span class="operator">,</span> <span class="keyword">this</span>); wordLabel<span class="operator">-</span><span class="operator">></span>move(x<span class="operator">,</span> y); wordLabel<span class="operator">-</span><span class="operator">></span>show(); wordLabel<span class="operator">-</span><span class="operator">></span>setAttribute(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>WA_DeleteOnClose); x <span class="operator">+</span><span class="operator">=</span> wordLabel<span class="operator">-</span><span class="operator">></span>width() <span class="operator">+</span> <span class="number">2</span>; <span class="keyword">if</span> (x <span class="operator">></span><span class="operator">=</span> <span class="number">245</span>) { x <span class="operator">=</span> <span class="number">5</span>; y <span class="operator">+</span><span class="operator">=</span> wordLabel<span class="operator">-</span><span class="operator">></span>height() <span class="operator">+</span> <span class="number">2</span>; } } } <span class="type"><a href="../qtgui/qpalette.html">QPalette</a></span> newPalette <span class="operator">=</span> palette(); newPalette<span class="operator">.</span>setColor(<span class="type"><a href="../qtgui/qpalette.html">QPalette</a></span><span class="operator">::</span>Window<span class="operator">,</span> <span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>white); setPalette(newPalette); setMinimumSize(<span class="number">400</span><span class="operator">,</span> <a href="../qtcore/qtglobal.html#qMax">qMax</a>(<span class="number">200</span><span class="operator">,</span> y)); setWindowTitle(tr(<span class="string">"Fridge Magnets"</span>)); setAcceptDrops(<span class="keyword">true</span>); } <span class="type">void</span> DragWidget<span class="operator">::</span>dragEnterEvent(<span class="type"><a href="../qtgui/qdragenterevent.html">QDragEnterEvent</a></span> <span class="operator">*</span>event) { <span class="keyword">if</span> (event<span class="operator">-</span><span class="operator">></span>mimeData()<span class="operator">-</span><span class="operator">></span>hasFormat(fridgetMagnetsMimeType())) { <span class="keyword">if</span> (children()<span class="operator">.</span>contains(event<span class="operator">-</span><span class="operator">></span>source())) { event<span class="operator">-</span><span class="operator">></span>setDropAction(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>MoveAction); event<span class="operator">-</span><span class="operator">></span>accept(); } <span class="keyword">else</span> { event<span class="operator">-</span><span class="operator">></span>acceptProposedAction(); } } <span class="keyword">else</span> <span class="keyword">if</span> (event<span class="operator">-</span><span class="operator">></span>mimeData()<span class="operator">-</span><span class="operator">></span>hasText()) { event<span class="operator">-</span><span class="operator">></span>acceptProposedAction(); } <span class="keyword">else</span> { event<span class="operator">-</span><span class="operator">></span>ignore(); } } <span class="type">void</span> DragWidget<span class="operator">::</span>dragMoveEvent(<span class="type"><a href="../qtgui/qdragmoveevent.html">QDragMoveEvent</a></span> <span class="operator">*</span>event) { <span class="keyword">if</span> (event<span class="operator">-</span><span class="operator">></span>mimeData()<span class="operator">-</span><span class="operator">></span>hasFormat(fridgetMagnetsMimeType())) { <span class="keyword">if</span> (children()<span class="operator">.</span>contains(event<span class="operator">-</span><span class="operator">></span>source())) { event<span class="operator">-</span><span class="operator">></span>setDropAction(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>MoveAction); event<span class="operator">-</span><span class="operator">></span>accept(); } <span class="keyword">else</span> { event<span class="operator">-</span><span class="operator">></span>acceptProposedAction(); } } <span class="keyword">else</span> <span class="keyword">if</span> (event<span class="operator">-</span><span class="operator">></span>mimeData()<span class="operator">-</span><span class="operator">></span>hasText()) { event<span class="operator">-</span><span class="operator">></span>acceptProposedAction(); } <span class="keyword">else</span> { event<span class="operator">-</span><span class="operator">></span>ignore(); } } <span class="type">void</span> DragWidget<span class="operator">::</span>dropEvent(<span class="type"><a href="../qtgui/qdropevent.html">QDropEvent</a></span> <span class="operator">*</span>event) { <span class="keyword">if</span> (event<span class="operator">-</span><span class="operator">></span>mimeData()<span class="operator">-</span><span class="operator">></span>hasFormat(fridgetMagnetsMimeType())) { <span class="keyword">const</span> <span class="type"><a href="../qtcore/qmimedata.html">QMimeData</a></span> <span class="operator">*</span>mime <span class="operator">=</span> event<span class="operator">-</span><span class="operator">></span>mimeData(); <span class="type"><a href="../qtcore/qbytearray.html">QByteArray</a></span> itemData <span class="operator">=</span> mime<span class="operator">-</span><span class="operator">></span>data(fridgetMagnetsMimeType()); <span class="type"><a href="../qtcore/qdatastream.html">QDataStream</a></span> dataStream(<span class="operator">&</span>itemData<span class="operator">,</span> <span class="type"><a href="../qtcore/qiodevice.html">QIODevice</a></span><span class="operator">::</span>ReadOnly); <span class="type"><a href="../qtcore/qstring.html">QString</a></span> text; <span class="type"><a href="../qtcore/qpoint.html">QPoint</a></span> offset; dataStream <span class="operator">></span><span class="operator">></span> text <span class="operator">></span><span class="operator">></span> offset; DragLabel <span class="operator">*</span>newLabel <span class="operator">=</span> <span class="keyword">new</span> DragLabel(text<span class="operator">,</span> <span class="keyword">this</span>); newLabel<span class="operator">-</span><span class="operator">></span>move(event<span class="operator">-</span><span class="operator">></span>pos() <span class="operator">-</span> offset); newLabel<span class="operator">-</span><span class="operator">></span>show(); newLabel<span class="operator">-</span><span class="operator">></span>setAttribute(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>WA_DeleteOnClose); <span class="keyword">if</span> (event<span class="operator">-</span><span class="operator">></span>source() <span class="operator">=</span><span class="operator">=</span> <span class="keyword">this</span>) { event<span class="operator">-</span><span class="operator">></span>setDropAction(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>MoveAction); event<span class="operator">-</span><span class="operator">></span>accept(); } <span class="keyword">else</span> { event<span class="operator">-</span><span class="operator">></span>acceptProposedAction(); } } <span class="keyword">else</span> <span class="keyword">if</span> (event<span class="operator">-</span><span class="operator">></span>mimeData()<span class="operator">-</span><span class="operator">></span>hasText()) { <span class="type"><a href="../qtcore/qstringlist.html">QStringList</a></span> pieces <span class="operator">=</span> event<span class="operator">-</span><span class="operator">></span>mimeData()<span class="operator">-</span><span class="operator">></span>text()<span class="operator">.</span>split(<span class="type"><a href="../qtcore/qregularexpression.html">QRegularExpression</a></span>(<span class="type"><a href="../qtcore/qstring.html#QStringLiteral">QStringLiteral</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); <span class="type"><a href="../qtcore/qpoint.html">QPoint</a></span> position <span class="operator">=</span> event<span class="operator">-</span><span class="operator">></span>pos(); <span class="keyword">for</span> (<span class="keyword">const</span> <span class="type"><a href="../qtcore/qstring.html">QString</a></span> <span class="operator">&</span>piece : pieces) { DragLabel <span class="operator">*</span>newLabel <span class="operator">=</span> <span class="keyword">new</span> DragLabel(piece<span class="operator">,</span> <span class="keyword">this</span>); newLabel<span class="operator">-</span><span class="operator">></span>move(position); newLabel<span class="operator">-</span><span class="operator">></span>show(); newLabel<span class="operator">-</span><span class="operator">></span>setAttribute(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>WA_DeleteOnClose); position <span class="operator">+</span><span class="operator">=</span> <span class="type"><a href="../qtcore/qpoint.html">QPoint</a></span>(newLabel<span class="operator">-</span><span class="operator">></span>width()<span class="operator">,</span> <span class="number">0</span>); } event<span class="operator">-</span><span class="operator">></span>acceptProposedAction(); } <span class="keyword">else</span> { event<span class="operator">-</span><span class="operator">></span>ignore(); } } <span class="type">void</span> DragWidget<span class="operator">::</span>mousePressEvent(<span class="type"><a href="../qtgui/qmouseevent.html">QMouseEvent</a></span> <span class="operator">*</span>event) { DragLabel <span class="operator">*</span>child <span class="operator">=</span> <span class="keyword">static_cast</span><span class="operator"><</span>DragLabel<span class="operator">*</span><span class="operator">></span>(childAt(event<span class="operator">-</span><span class="operator">></span>pos())); <span class="keyword">if</span> (<span class="operator">!</span>child) <span class="keyword">return</span>; <span class="type"><a href="../qtcore/qpoint.html">QPoint</a></span> hotSpot <span class="operator">=</span> event<span class="operator">-</span><span class="operator">></span>pos() <span class="operator">-</span> child<span class="operator">-</span><span class="operator">></span>pos(); <span class="type"><a href="../qtcore/qbytearray.html">QByteArray</a></span> itemData; <span class="type"><a href="../qtcore/qdatastream.html">QDataStream</a></span> dataStream(<span class="operator">&</span>itemData<span class="operator">,</span> <span class="type"><a href="../qtcore/qiodevice.html">QIODevice</a></span><span class="operator">::</span>WriteOnly); dataStream <span class="operator"><</span><span class="operator"><</span> child<span class="operator">-</span><span class="operator">></span>labelText() <span class="operator"><</span><span class="operator"><</span> <span class="type"><a href="../qtcore/qpoint.html">QPoint</a></span>(hotSpot); <span class="type"><a href="../qtcore/qmimedata.html">QMimeData</a></span> <span class="operator">*</span>mimeData <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="../qtcore/qmimedata.html">QMimeData</a></span>; mimeData<span class="operator">-</span><span class="operator">></span>setData(fridgetMagnetsMimeType()<span class="operator">,</span> itemData); mimeData<span class="operator">-</span><span class="operator">></span>setText(child<span class="operator">-</span><span class="operator">></span>labelText()); <span class="type"><a href="../qtgui/qdrag.html">QDrag</a></span> <span class="operator">*</span>drag <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="../qtgui/qdrag.html">QDrag</a></span>(<span class="keyword">this</span>); drag<span class="operator">-</span><span class="operator">></span>setMimeData(mimeData); drag<span class="operator">-</span><span class="operator">></span>setPixmap(<span class="operator">*</span>child<span class="operator">-</span><span class="operator">></span>pixmap()); drag<span class="operator">-</span><span class="operator">></span>setHotSpot(hotSpot); child<span class="operator">-</span><span class="operator">></span>hide(); <span class="keyword">if</span> (drag<span class="operator">-</span><span class="operator">></span>exec(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>MoveAction <span class="operator">|</span> <span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>CopyAction<span class="operator">,</span> <span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>CopyAction) <span class="operator">=</span><span class="operator">=</span> <span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>MoveAction) child<span class="operator">-</span><span class="operator">></span>close(); <span class="keyword">else</span> child<span class="operator">-</span><span class="operator">></span>show(); } </pre> </div> <!-- @@@draganddrop/fridgemagnets/dragwidget.cpp --> </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> </div> </body> </html>