Files
qt4-x11/doc/html/qdeclarativelistproperty.html
2025-08-24 20:55:26 +08:00

293 lines
18 KiB
HTML

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en_US" lang="en_US">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<!-- qdeclarativelist.cpp -->
<title>Qt 4.8: QDeclarativeListProperty Class Reference</title>
<link rel="stylesheet" type="text/css" href="style/style.css" />
<script src="scripts/jquery.js" type="text/javascript"></script>
<script src="scripts/functions.js" type="text/javascript"></script>
<link rel="stylesheet" type="text/css" href="style/superfish.css" />
<link rel="stylesheet" type="text/css" href="style/narrow.css" />
<!--[if IE]>
<meta name="MSSmartTagsPreventParsing" content="true">
<meta http-equiv="imagetoolbar" content="no">
<![endif]-->
<!--[if lt IE 7]>
<link rel="stylesheet" type="text/css" href="style/style_ie6.css">
<![endif]-->
<!--[if IE 7]>
<link rel="stylesheet" type="text/css" href="style/style_ie7.css">
<![endif]-->
<!--[if IE 8]>
<link rel="stylesheet" type="text/css" href="style/style_ie8.css">
<![endif]-->
<script src="scripts/superfish.js" type="text/javascript"></script>
<script src="scripts/narrow.js" type="text/javascript"></script>
</head>
<body class="" onload="CheckEmptyAndLoadList();">
<div class="header" id="qtdocheader">
<div class="content">
<div id="nav-logo">
<a href="index.html">Home</a></div>
<a href="index.html" class="qtref"><span>Qt Reference Documentation</span></a>
<div id="narrowsearch"></div>
<div id="nav-topright">
<ul>
<li class="nav-topright-home"><a href="http://qt.digia.com/">Qt HOME</a></li>
<li class="nav-topright-dev"><a href="http://qt-project.org/">DEV</a></li>
<li class="nav-topright-doc nav-topright-doc-active"><a href="http://qt-project.org/doc/">
DOC</a></li>
<li class="nav-topright-blog"><a href="http://blog.qt.digia.com/">BLOG</a></li>
</ul>
</div>
<div id="shortCut">
<ul>
<li class="shortCut-topleft-inactive"><span><a href="index.html">Qt 4.8</a></span></li>
<li class="shortCut-topleft-active"><a href="http://qt-project.org/doc/">ALL VERSIONS </a></li>
</ul>
</div>
<ul class="sf-menu" id="narrowmenu">
<li><a href="#">API Lookup</a>
<ul>
<li><a href="classes.html">Class index</a></li>
<li><a href="functions.html">Function index</a></li>
<li><a href="modules.html">Modules</a></li>
<li><a href="namespaces.html">Namespaces</a></li>
<li><a href="qtglobal.html">Global Declarations</a></li>
<li><a href="qdeclarativeelements.html">QML elements</a></li>
</ul>
</li>
<li><a href="#">Qt Topics</a>
<ul>
<li><a href="qt-basic-concepts.html">Programming with Qt</a></li>
<li><a href="qtquick.html">Device UIs &amp; Qt Quick</a></li>
<li><a href="qt-gui-concepts.html">UI Design with Qt</a></li>
<li><a href="supported-platforms.html">Supported Platforms</a></li>
<li><a href="technology-apis.html">Qt and Key Technologies</a></li>
<li><a href="best-practices.html">How-To's and Best Practices</a></li>
</ul>
</li>
<li><a href="#">Examples</a>
<ul>
<li><a href="all-examples.html">Examples</a></li>
<li><a href="tutorials.html">Tutorials</a></li>
<li><a href="demos.html">Demos</a></li>
<li><a href="qdeclarativeexamples.html">QML Examples</a></li>
</ul>
</li>
</ul>
</div>
</div>
<div class="wrapper">
<div class="hd">
<span></span>
</div>
<div class="bd group">
<div class="sidebar">
<div class="searchlabel">
Search index:</div>
<div class="search" id="sidebarsearch">
<form id="qtdocsearch" action="" onsubmit="return false;">
<fieldset>
<input type="text" name="searchstring" id="pageType" value="" />
<div id="resultdialog">
<a href="#" id="resultclose">Close</a>
<p id="resultlinks" class="all"><a href="#" id="showallresults">All</a> | <a href="#" id="showapiresults">API</a> | <a href="#" id="showarticleresults">Articles</a> | <a href="#" id="showexampleresults">Examples</a></p>
<p id="searchcount" class="all"><span id="resultcount"></span><span id="apicount"></span><span id="articlecount"></span><span id="examplecount"></span>&nbsp;results:</p>
<ul id="resultlist" class="all">
</ul>
</div>
</fieldset>
</form>
</div>
<div class="box first bottombar" id="lookup">
<h2 title="API Lookup"><span></span>
API Lookup</h2>
<div id="list001" class="list">
<ul id="ul001" >
<li class="defaultLink"><a href="classes.html">Class index</a></li>
<li class="defaultLink"><a href="functions.html">Function index</a></li>
<li class="defaultLink"><a href="modules.html">Modules</a></li>
<li class="defaultLink"><a href="namespaces.html">Namespaces</a></li>
<li class="defaultLink"><a href="qtglobal.html">Global Declarations</a></li>
<li class="defaultLink"><a href="qdeclarativeelements.html">QML elements</a></li>
</ul>
</div>
</div>
<div class="box bottombar" id="topics">
<h2 title="Qt Topics"><span></span>
Qt Topics</h2>
<div id="list002" class="list">
<ul id="ul002" >
<li class="defaultLink"><a href="qt-basic-concepts.html">Programming with Qt</a></li>
<li class="defaultLink"><a href="qtquick.html">Device UIs &amp; Qt Quick</a></li>
<li class="defaultLink"><a href="qt-gui-concepts.html">UI Design with Qt</a></li>
<li class="defaultLink"><a href="supported-platforms.html">Supported Platforms</a></li>
<li class="defaultLink"><a href="technology-apis.html">Qt and Key Technologies</a></li>
<li class="defaultLink"><a href="best-practices.html">How-To's and Best Practices</a></li>
</ul>
</div>
</div>
<div class="box" id="examples">
<h2 title="Examples"><span></span>
Examples</h2>
<div id="list003" class="list">
<ul id="ul003">
<li class="defaultLink"><a href="all-examples.html">Examples</a></li>
<li class="defaultLink"><a href="tutorials.html">Tutorials</a></li>
<li class="defaultLink"><a href="demos.html">Demos</a></li>
<li class="defaultLink"><a href="qdeclarativeexamples.html">QML Examples</a></li>
</ul>
</div>
</div>
</div>
<div class="wrap">
<div class="toolbar">
<div class="breadcrumb toolblock">
<ul>
<li class="first"><a href="index.html">Home</a></li>
<!-- Breadcrumbs go here -->
<li><a href="modules.html">Modules</a></li>
<li><a href="qtdeclarative.html">QtDeclarative</a></li>
<li>QDeclarativeListProperty</li>
</ul>
</div>
<div class="toolbuttons toolblock">
<ul>
<li id="smallA" class="t_button">A</li>
<li id="medA" class="t_button active">A</li>
<li id="bigA" class="t_button">A</li>
<li id="print" class="t_button"><a href="javascript:this.print();">
<span>Print</span></a></li>
</ul>
</div>
</div>
<div class="content mainContent">
<div class="toc">
<h3><a name="toc">Contents</a></h3>
<ul>
<li class="level1"><a href="#public-types">Public Types</a></li>
<li class="level1"><a href="#public-functions">Public Functions</a></li>
<li class="level1"><a href="#details">Detailed Description</a></li>
</ul>
</div>
<h1 class="title">QDeclarativeListProperty Class Reference</h1>
<!-- $$$QDeclarativeListProperty-brief -->
<p>The QDeclarativeListProperty class allows applications to expose list-like properties to QML. <a href="#details">More...</a></p>
<!-- @@@QDeclarativeListProperty -->
<pre class="cpp"> <span class="preprocessor">#include &lt;QDeclarativeListProperty&gt;</span></pre><p>This class was introduced in Qt 4.7.</p>
<ul>
<li><a href="qdeclarativelistproperty-members.html">List of all members, including inherited members</a></li>
</ul>
<a name="public-types"></a>
<h2>Public Types</h2>
<table class="alignedsummary">
<tr><td class="memItemLeft rightAlign topAlign"> typedef </td><td class="memItemRight bottomAlign"><b><a href="qdeclarativelistproperty.html#AppendFunction-typedef">AppendFunction</a></b></td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> typedef </td><td class="memItemRight bottomAlign"><b><a href="qdeclarativelistproperty.html#AtFunction-typedef">AtFunction</a></b></td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> typedef </td><td class="memItemRight bottomAlign"><b><a href="qdeclarativelistproperty.html#ClearFunction-typedef">ClearFunction</a></b></td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> typedef </td><td class="memItemRight bottomAlign"><b><a href="qdeclarativelistproperty.html#CountFunction-typedef">CountFunction</a></b></td></tr>
</table>
<a name="public-functions"></a>
<h2>Public Functions</h2>
<table class="alignedsummary">
<tr><td class="memItemLeft rightAlign topAlign"> </td><td class="memItemRight bottomAlign"><b><a href="qdeclarativelistproperty.html#QDeclarativeListProperty">QDeclarativeListProperty</a></b> ( QObject * <i>object</i>, QList&lt;T *&gt; &amp; <i>list</i> )</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> </td><td class="memItemRight bottomAlign"><b><a href="qdeclarativelistproperty.html#QDeclarativeListProperty-3">QDeclarativeListProperty</a></b> ( QObject * <i>object</i>, void * <i>data</i>, AppendFunction <i>append</i>, CountFunction <i>count</i> = 0, AtFunction <i>at</i> = 0, ClearFunction <i>clear</i> = 0 )</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> bool </td><td class="memItemRight bottomAlign"><b><a href="qdeclarativelistproperty.html#operator-eq-eq">operator==</a></b> ( const QDeclarativeListProperty &amp; <i>other</i> ) const</td></tr>
</table>
<a name="details"></a>
<!-- $$$QDeclarativeListProperty-description -->
<div class="descr">
<h2>Detailed Description</h2>
<p>The QDeclarativeListProperty class allows applications to expose list-like properties to QML.</p>
<p>QML has many list properties, where more than one object value can be assigned. The use of a list property from QML looks like this:</p>
<pre class="cpp"> FruitBasket {
fruit: <span class="operator">[</span>
Apple {}<span class="operator">,</span>
Orange{}<span class="operator">,</span>
Banana{}
<span class="operator">]</span>
}</pre>
<p>The QDeclarativeListProperty encapsulates a group of function pointers that represet the set of actions QML can perform on the list - adding items, retrieving items and clearing the list. In the future, additional operations may be supported. All list properties must implement the append operation, but the rest are optional.</p>
<p>To provide a list property, a C++ class must implement the operation callbacks, and then return an appropriate QDeclarativeListProperty value from the property getter. List properties should have no setter. In the example above, the <a href="qobject.html#Q_PROPERTY">Q_PROPERTY</a>() declarative will look like this:</p>
<pre class="cpp"> <a href="qobject.html#Q_PROPERTY">Q_PROPERTY</a>(<span class="type">QDeclarativeListProperty</span><span class="operator">&lt;</span>Fruit<span class="operator">&gt;</span> fruit READ fruit);</pre>
<p>QML list properties are typesafe - in this case <tt>Fruit</tt> is a <a href="qobject.html">QObject</a> type that <tt>Apple</tt>, <tt>Orange</tt> and <tt>Banana</tt> all derive from.</p>
<p><b>Note:</b> QDeclarativeListProperty can only be used for lists of <a href="qobject.html">QObject</a>-derived object pointers.</p>
</div>
<p><b>See also </b><a href="qml-extending.html#object-and-list-property-types">Object and List Property Types</a>.</p>
<!-- @@@QDeclarativeListProperty -->
<div class="types">
<h2>Member Type Documentation</h2>
<!-- $$$AppendFunction -->
<h3 class="fn"><a name="AppendFunction-typedef"></a>typedef QDeclarativeListProperty::<span class="name">AppendFunction</span></h3>
<p>Synonym for <tt>void (*)(QDeclarativeListProperty&lt;T&gt; *property, T *value)</tt>.</p>
<p>Append the <i>value</i> to the list <i>property</i>.</p>
<!-- @@@AppendFunction -->
<!-- $$$AtFunction -->
<h3 class="fn"><a name="AtFunction-typedef"></a>typedef QDeclarativeListProperty::<span class="name">AtFunction</span></h3>
<p>Synonym for <tt>T *(*)(QDeclarativeListProperty&lt;T&gt; *property, int index)</tt>.</p>
<p>Return the element at position <i>index</i> in the list <i>property</i>.</p>
<!-- @@@AtFunction -->
<!-- $$$ClearFunction -->
<h3 class="fn"><a name="ClearFunction-typedef"></a>typedef QDeclarativeListProperty::<span class="name">ClearFunction</span></h3>
<p>Synonym for <tt>void (*)(QDeclarativeListProperty&lt;T&gt; *property)</tt>.</p>
<p>Clear the list <i>property</i>.</p>
<!-- @@@ClearFunction -->
<!-- $$$CountFunction -->
<h3 class="fn"><a name="CountFunction-typedef"></a>typedef QDeclarativeListProperty::<span class="name">CountFunction</span></h3>
<p>Synonym for <tt>int (*)(QDeclarativeListProperty&lt;T&gt; *property)</tt>.</p>
<p>Return the number of elements in the list <i>property</i>.</p>
<!-- @@@CountFunction -->
</div>
<div class="func">
<h2>Member Function Documentation</h2>
<!-- $$$QDeclarativeListProperty[overload1]$$$QDeclarativeListPropertyQObject*QList<T*>& -->
<h3 class="fn"><a name="QDeclarativeListProperty"></a>QDeclarativeListProperty::<span class="name">QDeclarativeListProperty</span> ( <span class="type"><a href="qobject.html">QObject</a></span> * <i>object</i>, <span class="type"><a href="qlist.html">QList</a></span>&lt;<span class="type">T</span> *&gt; &amp; <i>list</i> )</h3>
<p>Convenience constructor for making a <a href="qdeclarativelistproperty.html">QDeclarativeListProperty</a> value from an existing <a href="qlist.html">QList</a> <i>list</i>. The <i>list</i> reference must remain valid for as long as <i>object</i> exists. <i>object</i> must be provided.</p>
<p>Generally this constructor should not be used in production code, as a writable <a href="qlist.html">QList</a> violates QML's memory management rules. However, this constructor can very useful while prototyping.</p>
<!-- @@@QDeclarativeListProperty -->
<!-- $$$QDeclarativeListProperty$$$QDeclarativeListPropertyQObject*void*AppendFunctionCountFunctionAtFunctionClearFunction -->
<h3 class="fn"><a name="QDeclarativeListProperty-3"></a>QDeclarativeListProperty::<span class="name">QDeclarativeListProperty</span> ( <span class="type"><a href="qobject.html">QObject</a></span> * <i>object</i>, <span class="type">void</span> * <i>data</i>, <span class="type"><a href="qdeclarativelistproperty.html#AppendFunction-typedef">AppendFunction</a></span> <i>append</i>, <span class="type"><a href="qdeclarativelistproperty.html#CountFunction-typedef">CountFunction</a></span> <i>count</i> = 0, <span class="type"><a href="qdeclarativelistproperty.html#AtFunction-typedef">AtFunction</a></span> <i>at</i> = 0, <span class="type"><a href="qdeclarativelistproperty.html#ClearFunction-typedef">ClearFunction</a></span> <i>clear</i> = 0 )</h3>
<p>Construct a <a href="qdeclarativelistproperty.html">QDeclarativeListProperty</a> from a set of operation functions. An opaque <i>data</i> handle may be passed which can be accessed from within the operation functions. The list property remains valid while <i>object</i> exists.</p>
<p>The <i>append</i> operation is compulsory and must be provided, while the <i>count</i>, <i>at</i> and <i>clear</i> methods are optional.</p>
<!-- @@@QDeclarativeListProperty -->
<!-- $$$operator==[overload1]$$$operator==constQDeclarativeListProperty& -->
<h3 class="fn"><a name="operator-eq-eq"></a><span class="type">bool</span> QDeclarativeListProperty::<span class="name">operator==</span> ( const <span class="type">QDeclarativeListProperty</span> &amp; <i>other</i> ) const</h3>
<p>Returns true if this <a href="qdeclarativelistproperty.html">QDeclarativeListProperty</a> is equal to <i>other</i>, otherwise false.</p>
<!-- @@@operator== -->
</div>
</div>
</div>
</div>
<div class="ft">
<span></span>
</div>
</div>
<div class="footer">
<p>
<acronym title="Copyright">&copy;</acronym> 2015 The Qt Company Ltd.
Documentation contributions included herein are the copyrights of
their respective owners.</p>
<br />
<p>
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.</p>
<p>
Documentation sources may be obtained from <a href="http://www.qt-project.org">
www.qt-project.org</a>.</p>
<br />
<p>
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. <a title="Privacy Policy"
href="http://en.gitorious.org/privacy_policy/">Privacy Policy</a></p>
</div>
<script src="scripts/functions.js" type="text/javascript"></script>
</body>
</html>