<?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>mdichild.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-mainwindows-mdi-example.html">MDI Example</a></td><td >mdichild.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">mdichild.cpp Example File</h1> <span class="subtitle">mainwindows/mdi/mdichild.cpp</span> <!-- $$$mainwindows/mdi/mdichild.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 <QtWidgets></span> <span class="preprocessor">#include "mdichild.h"</span> MdiChild<span class="operator">::</span>MdiChild() { setAttribute(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>WA_DeleteOnClose); isUntitled <span class="operator">=</span> <span class="keyword">true</span>; } <span class="type">void</span> MdiChild<span class="operator">::</span>newFile() { <span class="keyword">static</span> <span class="type">int</span> sequenceNumber <span class="operator">=</span> <span class="number">1</span>; isUntitled <span class="operator">=</span> <span class="keyword">true</span>; curFile <span class="operator">=</span> tr(<span class="string">"document%1.txt"</span>)<span class="operator">.</span>arg(sequenceNumber<span class="operator">+</span><span class="operator">+</span>); setWindowTitle(curFile <span class="operator">+</span> <span class="string">"[*]"</span>); connect(document()<span class="operator">,</span> <span class="operator">&</span><span class="type"><a href="../qtgui/qtextdocument.html">QTextDocument</a></span><span class="operator">::</span>contentsChanged<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> <span class="operator">&</span>MdiChild<span class="operator">::</span>documentWasModified); } bool MdiChild<span class="operator">::</span>loadFile(<span class="keyword">const</span> <span class="type"><a href="../qtcore/qstring.html">QString</a></span> <span class="operator">&</span>fileName) { <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="qmessagebox.html">QMessageBox</a></span><span class="operator">::</span>warning(<span class="keyword">this</span><span class="operator">,</span> tr(<span class="string">"MDI"</span>)<span class="operator">,</span> tr(<span class="string">"Cannot read file %1:\n%2."</span>) <span class="operator">.</span>arg(fileName) <span class="operator">.</span>arg(file<span class="operator">.</span>errorString())); <span class="keyword">return</span> <span class="keyword">false</span>; } <span class="type"><a href="../qtcore/qtextstream.html">QTextStream</a></span> in(<span class="operator">&</span>file); <span class="type"><a href="qapplication.html">QApplication</a></span><span class="operator">::</span>setOverrideCursor(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>WaitCursor); setPlainText(in<span class="operator">.</span>readAll()); <span class="type"><a href="qapplication.html">QApplication</a></span><span class="operator">::</span>restoreOverrideCursor(); setCurrentFile(fileName); connect(document()<span class="operator">,</span> <span class="operator">&</span><span class="type"><a href="../qtgui/qtextdocument.html">QTextDocument</a></span><span class="operator">::</span>contentsChanged<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> <span class="operator">&</span>MdiChild<span class="operator">::</span>documentWasModified); <span class="keyword">return</span> <span class="keyword">true</span>; } bool MdiChild<span class="operator">::</span>save() { <span class="keyword">if</span> (isUntitled) { <span class="keyword">return</span> saveAs(); } <span class="keyword">else</span> { <span class="keyword">return</span> saveFile(curFile); } } bool MdiChild<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="qfiledialog.html">QFileDialog</a></span><span class="operator">::</span>getSaveFileName(<span class="keyword">this</span><span class="operator">,</span> tr(<span class="string">"Save As"</span>)<span class="operator">,</span> curFile); <span class="keyword">if</span> (fileName<span class="operator">.</span>isEmpty()) <span class="keyword">return</span> <span class="keyword">false</span>; <span class="keyword">return</span> saveFile(fileName); } bool MdiChild<span class="operator">::</span>saveFile(<span class="keyword">const</span> <span class="type"><a href="../qtcore/qstring.html">QString</a></span> <span class="operator">&</span>fileName) { <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="qmessagebox.html">QMessageBox</a></span><span class="operator">::</span>warning(<span class="keyword">this</span><span class="operator">,</span> tr(<span class="string">"MDI"</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> <span class="keyword">false</span>; } <span class="type"><a href="../qtcore/qtextstream.html">QTextStream</a></span> out(<span class="operator">&</span>file); <span class="type"><a href="qapplication.html">QApplication</a></span><span class="operator">::</span>setOverrideCursor(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>WaitCursor); out <span class="operator"><</span><span class="operator"><</span> toPlainText(); <span class="type"><a href="qapplication.html">QApplication</a></span><span class="operator">::</span>restoreOverrideCursor(); setCurrentFile(fileName); <span class="keyword">return</span> <span class="keyword">true</span>; } <span class="type"><a href="../qtcore/qstring.html">QString</a></span> MdiChild<span class="operator">::</span>userFriendlyCurrentFile() { <span class="keyword">return</span> strippedName(curFile); } <span class="type">void</span> MdiChild<span class="operator">::</span>closeEvent(<span class="type"><a href="../qtgui/qcloseevent.html">QCloseEvent</a></span> <span class="operator">*</span>event) { <span class="keyword">if</span> (maybeSave()) { event<span class="operator">-</span><span class="operator">></span>accept(); } <span class="keyword">else</span> { event<span class="operator">-</span><span class="operator">></span>ignore(); } } <span class="type">void</span> MdiChild<span class="operator">::</span>documentWasModified() { setWindowModified(document()<span class="operator">-</span><span class="operator">></span>isModified()); } bool MdiChild<span class="operator">::</span>maybeSave() { <span class="keyword">if</span> (<span class="operator">!</span>document()<span class="operator">-</span><span class="operator">></span>isModified()) <span class="keyword">return</span> <span class="keyword">true</span>; <span class="keyword">const</span> <span class="type"><a href="qmessagebox.html">QMessageBox</a></span><span class="operator">::</span>StandardButton ret <span class="operator">=</span> <span class="type"><a href="qmessagebox.html">QMessageBox</a></span><span class="operator">::</span>warning(<span class="keyword">this</span><span class="operator">,</span> tr(<span class="string">"MDI"</span>)<span class="operator">,</span> tr(<span class="string">"'%1' has been modified.\n"</span> <span class="string">"Do you want to save your changes?"</span>) <span class="operator">.</span>arg(userFriendlyCurrentFile())<span class="operator">,</span> <span class="type"><a href="qmessagebox.html">QMessageBox</a></span><span class="operator">::</span>Save <span class="operator">|</span> <span class="type"><a href="qmessagebox.html">QMessageBox</a></span><span class="operator">::</span>Discard <span class="operator">|</span> <span class="type"><a href="qmessagebox.html">QMessageBox</a></span><span class="operator">::</span>Cancel); <span class="keyword">switch</span> (ret) { <span class="keyword">case</span> <span class="type"><a href="qmessagebox.html">QMessageBox</a></span><span class="operator">::</span>Save: <span class="keyword">return</span> save(); <span class="keyword">case</span> <span class="type"><a href="qmessagebox.html">QMessageBox</a></span><span class="operator">::</span>Cancel: <span class="keyword">return</span> <span class="keyword">false</span>; <span class="keyword">default</span>: <span class="keyword">break</span>; } <span class="keyword">return</span> <span class="keyword">true</span>; } <span class="type">void</span> MdiChild<span class="operator">::</span>setCurrentFile(<span class="keyword">const</span> <span class="type"><a href="../qtcore/qstring.html">QString</a></span> <span class="operator">&</span>fileName) { curFile <span class="operator">=</span> <span class="type"><a href="../qtcore/qfileinfo.html">QFileInfo</a></span>(fileName)<span class="operator">.</span>canonicalFilePath(); isUntitled <span class="operator">=</span> <span class="keyword">false</span>; document()<span class="operator">-</span><span class="operator">></span>setModified(<span class="keyword">false</span>); setWindowModified(<span class="keyword">false</span>); setWindowTitle(userFriendlyCurrentFile() <span class="operator">+</span> <span class="string">"[*]"</span>); } <span class="type"><a href="../qtcore/qstring.html">QString</a></span> MdiChild<span class="operator">::</span>strippedName(<span class="keyword">const</span> <span class="type"><a href="../qtcore/qstring.html">QString</a></span> <span class="operator">&</span>fullFileName) { <span class="keyword">return</span> <span class="type"><a href="../qtcore/qfileinfo.html">QFileInfo</a></span>(fullFileName)<span class="operator">.</span>fileName(); } </pre> </div> <!-- @@@mainwindows/mdi/mdichild.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>