<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE html> <html lang="en"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <!-- qjsvalueiterator.cpp --> <title>QJSValueIterator Class | Qt QML 5.9</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 5.9</td><td ><a href="qtqml-index.html">Qt QML</a></td><td ><a href="qtqml-module.html">C++ Classes</a></td><td >QJSValueIterator</td></tr></table><table class="buildversion"><tr> <td id="buildversion" width="100%" align="right">Qt 5.9.4 Reference Documentation</td> </tr></table> </div> </div> <div class="content"> <div class="line"> <div class="content mainContent"> <div class="sidebar"> <div class="toc"> <h3><a name="toc">Contents</a></h3> <ul> <li class="level1"><a href="#public-functions">Public Functions</a></li> <li class="level1"><a href="#details">Detailed Description</a></li> </ul> </div> <div class="sidebar-content" id="sidebar-content"></div></div> <h1 class="title">QJSValueIterator Class</h1> <!-- $$$QJSValueIterator-brief --> <p>The <a href="qjsvalueiterator.html">QJSValueIterator</a> class provides a Java-style iterator for <a href="qjsvalue.html">QJSValue</a>. <a href="#details">More...</a></p> <!-- @@@QJSValueIterator --> <div class="table"><table class="alignedsummary"> <tr><td class="memItemLeft rightAlign topAlign"> Header:</td><td class="memItemRight bottomAlign"> <span class="preprocessor">#include <QJSValueIterator></span> </td></tr><tr><td class="memItemLeft rightAlign topAlign"> qmake:</td><td class="memItemRight bottomAlign"> QT += qml</td></tr></table></div><ul> <li><a href="qjsvalueiterator-members.html">List of all members, including inherited members</a></li> </ul> <a name="public-functions"></a> <h2 id="public-functions">Public Functions</h2> <div class="table"><table class="alignedsummary"> <tr><td class="memItemLeft rightAlign topAlign"> </td><td class="memItemRight bottomAlign"><b><a href="qjsvalueiterator.html#QJSValueIterator">QJSValueIterator</a></b>(const QJSValue &<i>object</i>)</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> </td><td class="memItemRight bottomAlign"><b><a href="qjsvalueiterator.html#dtor.QJSValueIterator">~QJSValueIterator</a></b>()</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> bool </td><td class="memItemRight bottomAlign"><b><a href="qjsvalueiterator.html#hasNext">hasNext</a></b>() const</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> QString </td><td class="memItemRight bottomAlign"><b><a href="qjsvalueiterator.html#name">name</a></b>() const</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> bool </td><td class="memItemRight bottomAlign"><b><a href="qjsvalueiterator.html#next">next</a></b>()</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> QJSValue </td><td class="memItemRight bottomAlign"><b><a href="qjsvalueiterator.html#value">value</a></b>() const</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> QJSValueIterator &</td><td class="memItemRight bottomAlign"><b><a href="qjsvalueiterator.html#operator-eq">operator=</a></b>(QJSValue &<i>object</i>)</td></tr> </table></div> <a name="details"></a> <!-- $$$QJSValueIterator-description --> <div class="descr"> <h2 id="details">Detailed Description</h2> <p>The <a href="qjsvalueiterator.html">QJSValueIterator</a> class provides a Java-style iterator for <a href="qjsvalue.html">QJSValue</a>.</p> <p>The <a href="qjsvalueiterator.html">QJSValueIterator</a> constructor takes a <a href="qjsvalue.html">QJSValue</a> as argument. After construction, the iterator is located at the very beginning of the sequence of properties. Here's how to iterate over all the properties of a <a href="qjsvalue.html">QJSValue</a>:</p> <pre class="cpp"> <span class="type"><a href="qjsvalue.html">QJSValue</a></span> object; <span class="operator">.</span><span class="operator">.</span><span class="operator">.</span> <span class="type"><a href="qjsvalueiterator.html#QJSValueIterator">QJSValueIterator</a></span> it(object); <span class="keyword">while</span> (it<span class="operator">.</span>hasNext()) { it<span class="operator">.</span>next(); qDebug() <span class="operator"><</span><span class="operator"><</span> it<span class="operator">.</span>name() <span class="operator"><</span><span class="operator"><</span> <span class="string">": "</span> <span class="operator"><</span><span class="operator"><</span> it<span class="operator">.</span>value()<span class="operator">.</span>toString(); } </pre> <p>The <a href="qjsvalueiterator.html#next">next</a>() advances the iterator. The <a href="qjsvalueiterator.html#name">name</a>() and <a href="qjsvalueiterator.html#value">value</a>() functions return the name and value of the last item that was jumped over.</p> <p>Note that <a href="qjsvalueiterator.html">QJSValueIterator</a> only iterates over the <a href="qjsvalue.html">QJSValue</a>'s own properties; i.e. it does not follow the prototype chain. You can use a loop like this to follow the prototype chain:</p> <pre class="cpp"> <span class="type"><a href="qjsvalue.html">QJSValue</a></span> obj <span class="operator">=</span> <span class="operator">.</span><span class="operator">.</span><span class="operator">.</span>; <span class="comment">// the object to iterate over</span> <span class="keyword">while</span> (obj<span class="operator">.</span>isObject()) { <span class="type"><a href="qjsvalueiterator.html#QJSValueIterator">QJSValueIterator</a></span> it(obj); <span class="keyword">while</span> (it<span class="operator">.</span>hasNext()) { it<span class="operator">.</span>next(); qDebug() <span class="operator"><</span><span class="operator"><</span> it<span class="operator">.</span>name(); } obj <span class="operator">=</span> obj<span class="operator">.</span>prototype(); } </pre> </div> <p><b>See also </b><a href="qjsvalue.html#property">QJSValue::property</a>().</p> <!-- @@@QJSValueIterator --> <div class="func"> <h2>Member Function Documentation</h2> <!-- $$$QJSValueIterator[overload1]$$$QJSValueIteratorconstQJSValue& --> <h3 class="fn" id="QJSValueIterator"><a name="QJSValueIterator"></a>QJSValueIterator::<span class="name">QJSValueIterator</span>(const <span class="type"><a href="qjsvalue.html">QJSValue</a></span> &<i>object</i>)</h3> <p>Constructs an iterator for traversing <i>object</i>. The iterator is set to be at the front of the sequence of properties (before the first property).</p> <!-- @@@QJSValueIterator --> <!-- $$$~QJSValueIterator[overload1]$$$~QJSValueIterator --> <h3 class="fn" id="dtor.QJSValueIterator"><a name="dtor.QJSValueIterator"></a>QJSValueIterator::<span class="name">~QJSValueIterator</span>()</h3> <p>Destroys the iterator.</p> <!-- @@@~QJSValueIterator --> <!-- $$$hasNext[overload1]$$$hasNext --> <h3 class="fn" id="hasNext"><a name="hasNext"></a><span class="type">bool</span> QJSValueIterator::<span class="name">hasNext</span>() const</h3> <p>Returns true if there is at least one item ahead of the iterator (i.e. the iterator is <i>not</i> at the back of the property sequence); otherwise returns false.</p> <p><b>See also </b><a href="qjsvalueiterator.html#next">next</a>().</p> <!-- @@@hasNext --> <!-- $$$name[overload1]$$$name --> <h3 class="fn" id="name"><a name="name"></a><span class="type">QString</span> QJSValueIterator::<span class="name">name</span>() const</h3> <p>Returns the name of the last property that was jumped over using <a href="qjsvalueiterator.html#next">next</a>().</p> <p><b>See also </b><a href="qjsvalueiterator.html#value">value</a>().</p> <!-- @@@name --> <!-- $$$next[overload1]$$$next --> <h3 class="fn" id="next"><a name="next"></a><span class="type">bool</span> QJSValueIterator::<span class="name">next</span>()</h3> <p>Advances the iterator by one position. Returns true if there was at least one item ahead of the iterator (i.e. the iterator was <i>not</i> already at the back of the property sequence); otherwise returns false.</p> <p><b>See also </b><a href="qjsvalueiterator.html#hasNext">hasNext</a>() and <a href="qjsvalueiterator.html#name">name</a>().</p> <!-- @@@next --> <!-- $$$value[overload1]$$$value --> <h3 class="fn" id="value"><a name="value"></a><span class="type"><a href="qjsvalue.html">QJSValue</a></span> QJSValueIterator::<span class="name">value</span>() const</h3> <p>Returns the value of the last property that was jumped over using <a href="qjsvalueiterator.html#next">next</a>().</p> <p><b>See also </b><a href="qjsvalueiterator.html#name">name</a>().</p> <!-- @@@value --> <!-- $$$operator=[overload1]$$$operator=QJSValue& --> <h3 class="fn" id="operator-eq"><a name="operator-eq"></a><span class="type"><a href="qjsvalueiterator.html#QJSValueIterator">QJSValueIterator</a></span> &QJSValueIterator::<span class="name">operator=</span>(<span class="type"><a href="qjsvalue.html">QJSValue</a></span> &<i>object</i>)</h3> <p>Makes the iterator operate on <i>object</i>. The iterator is set to be at the front of the sequence of properties (before the first property).</p> <!-- @@@operator= --> </div> </div> </div> </div> </div> </div> <div class="footer"> <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 of their respective owners. </p> </div> </body> </html>