<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE html> <html lang="en"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <!-- basictypes.qdoc --> <title>list QML Basic Type | 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-qmlmodule.html">QML Types</a></td><td >list QML Basic Type</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="#using-the-list-type">Using the list Type</a></li> </ul> </div> <div class="sidebar-content" id="sidebar-content"></div></div> <h1 class="title">list QML Basic Type</h1> <span class="subtitle"></span> <!-- $$$list-description --> <div class="descr"> <a name="details"></a> <p>a list of QML objects.</p> <p>The <code>list</code> type refers to a list of QML objects.</p> <p>A list value can be accessed in a similar way to a JavaScript array:</p> <ul> <li>Values are assigned using the <code>[]</code> square bracket syntax with comma-separated values</li> <li>The <code>length</code> property provides the number of items in the list</li> <li>Values in the list are accessed using the <code>[index]</code> syntax</li> </ul> <p>Values can be dynamically added to the list by using the <code>push</code> method, as if it were a JavaScript Array</p> <p>A <code>list</code> can only store QML objects, and cannot contain any <a href="qtqml-typesystem-basictypes.html">basic type</a> values. (To store basic types within a list, use the <a href="qml-var.html">var</a> type instead.)</p> <p>When integrating with C++, note that any <a href="qqmllistproperty.html">QQmlListProperty</a> value <a href="qtqml-cppintegration-data.html">passed into QML from C++</a> is automatically converted into a <code>list</code> value, and vice-versa.</p> <a name="using-the-list-type"></a> <h2 id="using-the-list-type">Using the list Type</h2> <p>For example, the Item type has a states list-type property that can be assigned to and used as follows:</p> <pre class="qml"> import QtQuick 2.0 <span class="type">Item</span> { <span class="name">width</span>: <span class="number">100</span>; <span class="name">height</span>: <span class="number">100</span> <span class="name">states</span>: [ <span class="type"><a href="qml-qtqml-statemachine-state.html">State</a></span> { <span class="name">name</span>: <span class="string">"activated"</span> }, <span class="type"><a href="qml-qtqml-statemachine-state.html">State</a></span> { <span class="name">name</span>: <span class="string">"deactivated"</span> } ] <span class="name">Component</span>.onCompleted: { <span class="name">console</span>.<span class="name">log</span>(<span class="string">"Name of first state:"</span>, <span class="name">states</span>[<span class="number">0</span>].<span class="name">name</span>) <span class="keyword">for</span> (<span class="keyword">var</span> <span class="name">i</span> = <span class="number">0</span>; <span class="name">i</span> <span class="operator"><</span> <span class="name">states</span>.<span class="name">length</span>; i++) <span class="name">console</span>.<span class="name">log</span>(<span class="string">"state"</span>, <span class="name">i</span>, <span class="name">states</span>[<span class="name">i</span>].<span class="name">name</span>) } } </pre> <p>The defined <a href="qml-qtqml-statemachine-state.html">State</a> objects will be added to the <code>states</code> list in the order in which they are defined.</p> <p>If the list only contains one object, the square brackets may be omitted:</p> <pre class="qml"> import QtQuick 2.0 <span class="type">Item</span> { <span class="name">width</span>: <span class="number">100</span>; <span class="name">height</span>: <span class="number">100</span> <span class="name">states</span>: <span class="name">State</span> { <span class="name">name</span>: <span class="string">"activated"</span> } } </pre> <p>Note that objects cannot be individually added to or removed from the list once created; to modify the contents of a list, it must be reassigned to a new list.</p> <p><b>Note: </b>The <code>list</code> type is not recommended as a type for custom properties. The <code>var</code> type should be used instead for this purpose as lists stored by the <code>var</code> type can be manipulated with greater flexibility from within QML.</p><p>This basic type is provided by the QML language.</p> </div> <p><b>See also </b><a href="qtqml-typesystem-basictypes.html">QML Basic Types</a>.</p> <!-- @@@list --> </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>