<?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" />
<!-- customcompleter.qdoc -->
<title>Qt 4.8: Custom Completer Example</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 & 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> 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 & 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="all-examples.html">Examples</a></li>
<li>Custom Completer Example</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="#setting-up-the-resource-file">Setting Up The Resource File</a></li>
<li class="level1"><a href="#textedit-class-definition">TextEdit Class Definition</a></li>
<li class="level1"><a href="#textedit-class-implementation">TextEdit Class Implementation</a></li>
<li class="level1"><a href="#mainwindow-class-definition">MainWindow Class Definition</a></li>
<li class="level1"><a href="#mainwindow-class-implementation">MainWindow Class Implementation</a></li>
<li class="level1"><a href="#function"><tt>main()</tt> Function</a></li>
</ul>
</div>
<h1 class="title">Custom Completer Example</h1>
<span class="subtitle"></span>
<!-- $$$tools/customcompleter-description -->
<div class="descr"> <a name="details"></a>
<p>Files:</p>
<ul>
<li><a href="tools-customcompleter-mainwindow-cpp.html">tools/customcompleter/mainwindow.cpp</a></li>
<li><a href="tools-customcompleter-mainwindow-h.html">tools/customcompleter/mainwindow.h</a></li>
<li><a href="tools-customcompleter-textedit-cpp.html">tools/customcompleter/textedit.cpp</a></li>
<li><a href="tools-customcompleter-textedit-h.html">tools/customcompleter/textedit.h</a></li>
<li><a href="tools-customcompleter-main-cpp.html">tools/customcompleter/main.cpp</a></li>
<li><a href="tools-customcompleter-customcompleter-pro.html">tools/customcompleter/customcompleter.pro</a></li>
<li><a href="tools-customcompleter-customcompleter-qrc.html">tools/customcompleter/customcompleter.qrc</a></li>
</ul>
<p>The Custom Completer example shows how to provide string-completion facilities for an input widget based on data provided by a model. The completer pops up suggestions for possible words based on the first three characters input by the user and the user's choice of word is inserted into the <tt>TextEdit</tt> using <a href="qtextcursor.html">QTextCursor</a>.<p class="centerAlign"><img src="images/customcompleter-example.png" alt="" /></p><a name="setting-up-the-resource-file"></a>
<h2>Setting Up The Resource File</h2>
<p>The Custom Completer example requires a resource file, <i>wordlist.txt</i>, that has a list of words to help <a href="qcompleter.html">QCompleter</a> complete words. This file contains the following:</p>
<pre class="cpp"> <!DOCTYPE RCC><RCC version="1.0">
<qresource prefix="/">
<file>resources/wordlist.txt</file>
</qresource>
</RCC></pre>
<a name="textedit-class-definition"></a>
<h2>TextEdit Class Definition</h2>
<p>The <tt>TextEdit</tt> class is a subclass of <a href="qtextedit.html">QTextEdit</a> with a custom <tt>insertCompletion()</tt> slot and it reimplements the <a href="qabstractscrollarea.html#keyPressEvent">keyPressEvent()</a> and the <a href="qwidget.html#focusInEvent">focusInEvent()</a> functions. <tt>TextEdit</tt> also contains a private function <tt>textUnderCursor()</tt> and a private instance of <a href="qcompleter.html">QCompleter</a>, <tt>c</tt>.</p>
<pre class="cpp"> <span class="keyword">class</span> TextEdit : <span class="keyword">public</span> <span class="type"><a href="qtextedit.html">QTextEdit</a></span>
{
Q_OBJECT
<span class="keyword">public</span>:
TextEdit(<span class="type"><a href="qwidget.html">QWidget</a></span> <span class="operator">*</span>parent <span class="operator">=</span> <span class="number">0</span>);
<span class="operator">~</span>TextEdit();
<span class="type">void</span> setCompleter(<span class="type"><a href="qcompleter.html">QCompleter</a></span> <span class="operator">*</span>c);
<span class="type"><a href="qcompleter.html">QCompleter</a></span> <span class="operator">*</span>completer() <span class="keyword">const</span>;
<span class="keyword">protected</span>:
<span class="type">void</span> keyPressEvent(<span class="type"><a href="qkeyevent.html">QKeyEvent</a></span> <span class="operator">*</span>e);
<span class="type">void</span> focusInEvent(<span class="type"><a href="qfocusevent.html">QFocusEvent</a></span> <span class="operator">*</span>e);
<span class="keyword">private</span> <span class="keyword">slots</span>:
<span class="type">void</span> insertCompletion(<span class="keyword">const</span> <span class="type"><a href="qstring.html">QString</a></span> <span class="operator">&</span>completion);
<span class="keyword">private</span>:
<span class="type"><a href="qstring.html">QString</a></span> textUnderCursor() <span class="keyword">const</span>;
<span class="keyword">private</span>:
<span class="type"><a href="qcompleter.html">QCompleter</a></span> <span class="operator">*</span>c;
};</pre>
<a name="textedit-class-implementation"></a>
<h2>TextEdit Class Implementation</h2>
<p>The constructor for <tt>TextEdit</tt> constructs a <tt>TextEdit</tt> with a parent and initializes <tt>c</tt>. The instructions to use the completer is displayed on the <tt>TextEdit</tt> object, using the <a href="qtextedit.html#plainText-prop">setPlainText()</a> function.</p>
<pre class="cpp"> TextEdit<span class="operator">::</span>TextEdit(<span class="type"><a href="qwidget.html">QWidget</a></span> <span class="operator">*</span>parent)
: <span class="type"><a href="qtextedit.html">QTextEdit</a></span>(parent)<span class="operator">,</span> c(<span class="number">0</span>)
{
setPlainText(tr(<span class="string">"This TextEdit provides autocompletions for words that have more than"</span>
<span class="string">" 3 characters. You can trigger autocompletion using "</span>) <span class="operator">+</span>
<span class="type"><a href="qkeysequence.html">QKeySequence</a></span>(<span class="string">"Ctrl+E"</span>)<span class="operator">.</span>toString(<span class="type"><a href="qkeysequence.html">QKeySequence</a></span><span class="operator">::</span>NativeText));
}</pre>
<p>In addition, <tt>TextEdit</tt> also includes a default destructor:</p>
<pre class="cpp"> TextEdit<span class="operator">::</span><span class="operator">~</span>TextEdit()
{
}</pre>
<p>The <tt>setCompleter()</tt> function accepts a <i>completer</i> and sets it up. We use <tt>if (c)</tt> to check if <tt>c</tt> has been initialized. If it has been initialized, the <a href="qobject.html#disconnect">QObject::disconnect</a>() function is invoked to disconnect the signal from the slot. This is to ensure that no previous completer object is still connected to the slot.</p>
<pre class="cpp"> <span class="type">void</span> TextEdit<span class="operator">::</span>setCompleter(<span class="type"><a href="qcompleter.html">QCompleter</a></span> <span class="operator">*</span>completer)
{
<span class="keyword">if</span> (c)
<span class="type"><a href="qobject.html">QObject</a></span><span class="operator">::</span>disconnect(c<span class="operator">,</span> <span class="number">0</span><span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> <span class="number">0</span>);
c <span class="operator">=</span> completer;
<span class="keyword">if</span> (<span class="operator">!</span>c)
<span class="keyword">return</span>;
c<span class="operator">-</span><span class="operator">></span>setWidget(<span class="keyword">this</span>);
c<span class="operator">-</span><span class="operator">></span>setCompletionMode(<span class="type"><a href="qcompleter.html">QCompleter</a></span><span class="operator">::</span>PopupCompletion);
c<span class="operator">-</span><span class="operator">></span>setCaseSensitivity(<span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>CaseInsensitive);
<span class="type"><a href="qobject.html">QObject</a></span><span class="operator">::</span>connect(c<span class="operator">,</span> SIGNAL(activated(<span class="type"><a href="qstring.html">QString</a></span>))<span class="operator">,</span>
<span class="keyword">this</span><span class="operator">,</span> SLOT(insertCompletion(<span class="type"><a href="qstring.html">QString</a></span>)));
}</pre>
<p>We then instantiate <tt>c</tt> with <i>completer</i> and set it as <tt>TextEdit</tt>'s widget. The completion mode and case sensitivity are also set and then we connect the <a href="qcompleter.html#activated">activated()</a> signal to the <tt>insertCompletion()</tt> slot.</p>
<p>The <tt>completer()</tt> function is a getter function that returns <tt>c</tt>.</p>
<pre class="cpp"> <span class="type"><a href="qcompleter.html">QCompleter</a></span> <span class="operator">*</span>TextEdit<span class="operator">::</span>completer() <span class="keyword">const</span>
{
<span class="keyword">return</span> c;
}</pre>
<p>The completer pops up the options available, based on the contents of <i>wordlist.txt</i>, but the text cursor is responsible for filling in the missing characters, according to the user's choice of word.</p>
<p>Suppose the user inputs "ACT" and accepts the completer's suggestion of "ACTUAL". The <tt>completion</tt> string is then sent to <tt>insertCompletion()</tt> by the completer's <a href="qcompleter.html#activated">activated()</a> signal.</p>
<p>The <tt>insertCompletion()</tt> function is responsible for completing the word using a <a href="qtextcursor.html">QTextCursor</a> object, <tt>tc</tt>. It validates to ensure that the completer's widget is <tt>TextEdit</tt> before using <tt>tc</tt> to insert the extra characters to complete the word.</p>
<pre class="cpp"> <span class="type">void</span> TextEdit<span class="operator">::</span>insertCompletion(<span class="keyword">const</span> <span class="type"><a href="qstring.html">QString</a></span><span class="operator">&</span> completion)
{
<span class="keyword">if</span> (c<span class="operator">-</span><span class="operator">></span>widget() <span class="operator">!</span><span class="operator">=</span> <span class="keyword">this</span>)
<span class="keyword">return</span>;
<span class="type"><a href="qtextcursor.html">QTextCursor</a></span> tc <span class="operator">=</span> textCursor();
<span class="type">int</span> extra <span class="operator">=</span> completion<span class="operator">.</span>length() <span class="operator">-</span> c<span class="operator">-</span><span class="operator">></span>completionPrefix()<span class="operator">.</span>length();
tc<span class="operator">.</span>movePosition(<span class="type"><a href="qtextcursor.html">QTextCursor</a></span><span class="operator">::</span>Left);
tc<span class="operator">.</span>movePosition(<span class="type"><a href="qtextcursor.html">QTextCursor</a></span><span class="operator">::</span>EndOfWord);
tc<span class="operator">.</span>insertText(completion<span class="operator">.</span>right(extra));
setTextCursor(tc);
}</pre>
<p>The figure below illustrates this process:</p>
<p class="centerAlign"><img src="images/customcompleter-insertcompletion.png" alt="" /></p><p><tt>completion.length()</tt> = 6</p>
<p><tt>c->completionPrefix().length()</tt>=3</p>
<p>The difference between these two values is <tt>extra</tt>, which is 3. This means that the last three characters from the right, "U", "A", and "L", will be inserted by <tt>tc</tt>.</p>
<p>The <tt>textUnderCursor()</tt> function uses a <a href="qtextcursor.html">QTextCursor</a>, <tt>tc</tt>, to select a word under the cursor and return it.</p>
<pre class="cpp"> <span class="type"><a href="qstring.html">QString</a></span> TextEdit<span class="operator">::</span>textUnderCursor() <span class="keyword">const</span>
{
<span class="type"><a href="qtextcursor.html">QTextCursor</a></span> tc <span class="operator">=</span> textCursor();
tc<span class="operator">.</span>select(<span class="type"><a href="qtextcursor.html">QTextCursor</a></span><span class="operator">::</span>WordUnderCursor);
<span class="keyword">return</span> tc<span class="operator">.</span>selectedText();
}</pre>
<p>The <tt>TextEdit</tt> class reimplements <a href="qwidget.html#focusInEvent">focusInEvent()</a> function, which is an event handler used to receive keyboard focus events for the widget.</p>
<pre class="cpp"> <span class="type">void</span> TextEdit<span class="operator">::</span>focusInEvent(<span class="type"><a href="qfocusevent.html">QFocusEvent</a></span> <span class="operator">*</span>e)
{
<span class="keyword">if</span> (c)
c<span class="operator">-</span><span class="operator">></span>setWidget(<span class="keyword">this</span>);
<span class="type"><a href="qtextedit.html">QTextEdit</a></span><span class="operator">::</span>focusInEvent(e);
}</pre>
<p>The <a href="qabstractscrollarea.html#keyPressEvent">keyPressEvent()</a> is reimplemented to ignore key events like <a href="qt.html#Key-enum">Qt::Key_Enter</a>, <a href="qt.html#Key-enum">Qt::Key_Return</a>, <a href="qt.html#Key-enum">Qt::Key_Escape</a>, <a href="qt.html#Key-enum">Qt::Key_Tab</a>, and <a href="qt.html#Key-enum">Qt::Key_Backtab</a> so the completer can handle them.</p>
<p>If there is an active completer, we cannot process the shortcut, Ctrl+E.</p>
<pre class="cpp"> <span class="type">void</span> TextEdit<span class="operator">::</span>keyPressEvent(<span class="type"><a href="qkeyevent.html">QKeyEvent</a></span> <span class="operator">*</span>e)
{
<span class="keyword">if</span> (c <span class="operator">&</span><span class="operator">&</span> c<span class="operator">-</span><span class="operator">></span>popup()<span class="operator">-</span><span class="operator">></span>isVisible()) {
<span class="comment">// The following keys are forwarded by the completer to the widget</span>
<span class="keyword">switch</span> (e<span class="operator">-</span><span class="operator">></span>key()) {
<span class="keyword">case</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>Key_Enter:
<span class="keyword">case</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>Key_Return:
<span class="keyword">case</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>Key_Escape:
<span class="keyword">case</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>Key_Tab:
<span class="keyword">case</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>Key_Backtab:
e<span class="operator">-</span><span class="operator">></span>ignore();
<span class="keyword">return</span>; <span class="comment">// let the completer do default behavior</span>
<span class="keyword">default</span>:
<span class="keyword">break</span>;
}
}
<span class="type">bool</span> isShortcut <span class="operator">=</span> ((e<span class="operator">-</span><span class="operator">></span>modifiers() <span class="operator">&</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>ControlModifier) <span class="operator">&</span><span class="operator">&</span> e<span class="operator">-</span><span class="operator">></span>key() <span class="operator">=</span><span class="operator">=</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>Key_E); <span class="comment">// CTRL+E</span>
<span class="keyword">if</span> (<span class="operator">!</span>c <span class="operator">|</span><span class="operator">|</span> <span class="operator">!</span>isShortcut) <span class="comment">// do not process the shortcut when we have a completer</span>
<span class="type"><a href="qtextedit.html">QTextEdit</a></span><span class="operator">::</span>keyPressEvent(e);</pre>
<p>We also handle other modifiers and shortcuts for which we do not want the completer to respond to.</p>
<pre class="cpp"> <span class="keyword">const</span> <span class="type">bool</span> ctrlOrShift <span class="operator">=</span> e<span class="operator">-</span><span class="operator">></span>modifiers() <span class="operator">&</span> (<span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>ControlModifier <span class="operator">|</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>ShiftModifier);
<span class="keyword">if</span> (<span class="operator">!</span>c <span class="operator">|</span><span class="operator">|</span> (ctrlOrShift <span class="operator">&</span><span class="operator">&</span> e<span class="operator">-</span><span class="operator">></span>text()<span class="operator">.</span>isEmpty()))
<span class="keyword">return</span>;
<span class="keyword">static</span> <span class="type"><a href="qstring.html">QString</a></span> eow(<span class="string">"~!@#$%^&*()_+{}|:\"<>?,./;'[]\\-="</span>); <span class="comment">// end of word</span>
<span class="type">bool</span> hasModifier <span class="operator">=</span> (e<span class="operator">-</span><span class="operator">></span>modifiers() <span class="operator">!</span><span class="operator">=</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>NoModifier) <span class="operator">&</span><span class="operator">&</span> <span class="operator">!</span>ctrlOrShift;
<span class="type"><a href="qstring.html">QString</a></span> completionPrefix <span class="operator">=</span> textUnderCursor();
<span class="keyword">if</span> (<span class="operator">!</span>isShortcut <span class="operator">&</span><span class="operator">&</span> (hasModifier <span class="operator">|</span><span class="operator">|</span> e<span class="operator">-</span><span class="operator">></span>text()<span class="operator">.</span>isEmpty()<span class="operator">|</span><span class="operator">|</span> completionPrefix<span class="operator">.</span>length() <span class="operator"><</span> <span class="number">3</span>
<span class="operator">|</span><span class="operator">|</span> eow<span class="operator">.</span>contains(e<span class="operator">-</span><span class="operator">></span>text()<span class="operator">.</span>right(<span class="number">1</span>)))) {
c<span class="operator">-</span><span class="operator">></span>popup()<span class="operator">-</span><span class="operator">></span>hide();
<span class="keyword">return</span>;
}
<span class="keyword">if</span> (completionPrefix <span class="operator">!</span><span class="operator">=</span> c<span class="operator">-</span><span class="operator">></span>completionPrefix()) {
c<span class="operator">-</span><span class="operator">></span>setCompletionPrefix(completionPrefix);
c<span class="operator">-</span><span class="operator">></span>popup()<span class="operator">-</span><span class="operator">></span>setCurrentIndex(c<span class="operator">-</span><span class="operator">></span>completionModel()<span class="operator">-</span><span class="operator">></span>index(<span class="number">0</span><span class="operator">,</span> <span class="number">0</span>));
}
<span class="type"><a href="qrect.html">QRect</a></span> cr <span class="operator">=</span> cursorRect();
cr<span class="operator">.</span>setWidth(c<span class="operator">-</span><span class="operator">></span>popup()<span class="operator">-</span><span class="operator">></span>sizeHintForColumn(<span class="number">0</span>)
<span class="operator">+</span> c<span class="operator">-</span><span class="operator">></span>popup()<span class="operator">-</span><span class="operator">></span>verticalScrollBar()<span class="operator">-</span><span class="operator">></span>sizeHint()<span class="operator">.</span>width());
c<span class="operator">-</span><span class="operator">></span>complete(cr); <span class="comment">// popup it up!</span>
}</pre>
<p>Finally, we pop up the completer.</p>
<a name="mainwindow-class-definition"></a>
<h2>MainWindow Class Definition</h2>
<p>The <tt>MainWindow</tt> class is a subclass of <a href="qmainwindow.html">QMainWindow</a> and implements a private slot, <tt>about()</tt>. This class also has two private functions, <tt>createMenu()</tt> and <tt>modelFromFile()</tt> as well as private instances of <a href="qcompleter.html">QCompleter</a> and <tt>TextEdit</tt>.</p>
<pre class="cpp"> <span class="keyword">class</span> MainWindow : <span class="keyword">public</span> <span class="type"><a href="qmainwindow.html">QMainWindow</a></span>
{
Q_OBJECT
<span class="keyword">public</span>:
MainWindow(<span class="type"><a href="qwidget.html">QWidget</a></span> <span class="operator">*</span>parent <span class="operator">=</span> <span class="number">0</span>);
<span class="keyword">private</span> <span class="keyword">slots</span>:
<span class="type">void</span> about();
<span class="keyword">private</span>:
<span class="type">void</span> createMenu();
<span class="type"><a href="qabstractitemmodel.html">QAbstractItemModel</a></span> <span class="operator">*</span>modelFromFile(<span class="keyword">const</span> <span class="type"><a href="qstring.html">QString</a></span><span class="operator">&</span> fileName);
<span class="type"><a href="qcompleter.html">QCompleter</a></span> <span class="operator">*</span>completer;
TextEdit <span class="operator">*</span>completingTextEdit;
};</pre>
<a name="mainwindow-class-implementation"></a>
<h2>MainWindow Class Implementation</h2>
<p>The constructor constructs a <tt>MainWindow</tt> with a parent and initializes the <tt>completer</tt>. It also instantiates a <tt>TextEdit</tt> and sets its completer. A <a href="qstringlistmodel.html">QStringListModel</a>, obtained from <tt>modelFromFile()</tt>, is used to populate the <tt>completer</tt>. The <tt>MainWindow</tt>'s central widget is set to <tt>TextEdit</tt> and its size is set to 500 x 300.</p>
<pre class="cpp"> MainWindow<span class="operator">::</span>MainWindow(<span class="type"><a href="qwidget.html">QWidget</a></span> <span class="operator">*</span>parent)
: <span class="type"><a href="qmainwindow.html">QMainWindow</a></span>(parent)<span class="operator">,</span> completer(<span class="number">0</span>)
{
createMenu();
completingTextEdit <span class="operator">=</span> <span class="keyword">new</span> TextEdit;
completer <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qcompleter.html">QCompleter</a></span>(<span class="keyword">this</span>);
completer<span class="operator">-</span><span class="operator">></span>setModel(modelFromFile(<span class="string">":/resources/wordlist.txt"</span>));
completer<span class="operator">-</span><span class="operator">></span>setModelSorting(<span class="type"><a href="qcompleter.html">QCompleter</a></span><span class="operator">::</span>CaseInsensitivelySortedModel);
completer<span class="operator">-</span><span class="operator">></span>setCaseSensitivity(<span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>CaseInsensitive);
completer<span class="operator">-</span><span class="operator">></span>setWrapAround(<span class="keyword">false</span>);
completingTextEdit<span class="operator">-</span><span class="operator">></span>setCompleter(completer);
setCentralWidget(completingTextEdit);
resize(<span class="number">500</span><span class="operator">,</span> <span class="number">300</span>);
setWindowTitle(tr(<span class="string">"Completer"</span>));
}</pre>
<p>The <tt>createMenu()</tt> function creates the necessary <a href="qaction.html">QAction</a> objects needed for the "File" and "Help" menu and their <a href="qaction.html#triggered">triggered()</a> signals are connected to the <tt>quit()</tt>, <tt>about()</tt>, and <tt>aboutQt()</tt> slots respectively.</p>
<pre class="cpp"> <span class="type">void</span> MainWindow<span class="operator">::</span>createMenu()
{
<span class="type"><a href="qaction.html">QAction</a></span> <span class="operator">*</span>exitAction <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qaction.html">QAction</a></span>(tr(<span class="string">"Exit"</span>)<span class="operator">,</span> <span class="keyword">this</span>);
<span class="type"><a href="qaction.html">QAction</a></span> <span class="operator">*</span>aboutAct <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qaction.html">QAction</a></span>(tr(<span class="string">"About"</span>)<span class="operator">,</span> <span class="keyword">this</span>);
<span class="type"><a href="qaction.html">QAction</a></span> <span class="operator">*</span>aboutQtAct <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qaction.html">QAction</a></span>(tr(<span class="string">"About Qt"</span>)<span class="operator">,</span> <span class="keyword">this</span>);
connect(exitAction<span class="operator">,</span> SIGNAL(triggered())<span class="operator">,</span> qApp<span class="operator">,</span> SLOT(quit()));
connect(aboutAct<span class="operator">,</span> SIGNAL(triggered())<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> SLOT(about()));
connect(aboutQtAct<span class="operator">,</span> SIGNAL(triggered())<span class="operator">,</span> qApp<span class="operator">,</span> SLOT(aboutQt()));
<span class="type"><a href="qmenu.html">QMenu</a></span><span class="operator">*</span> fileMenu <span class="operator">=</span> menuBar()<span class="operator">-</span><span class="operator">></span>addMenu(tr(<span class="string">"File"</span>));
fileMenu<span class="operator">-</span><span class="operator">></span>addAction(exitAction);
<span class="type"><a href="qmenu.html">QMenu</a></span><span class="operator">*</span> helpMenu <span class="operator">=</span> menuBar()<span class="operator">-</span><span class="operator">></span>addMenu(tr(<span class="string">"About"</span>));
helpMenu<span class="operator">-</span><span class="operator">></span>addAction(aboutAct);
helpMenu<span class="operator">-</span><span class="operator">></span>addAction(aboutQtAct);
}</pre>
<p>The <tt>modelFromFile()</tt> function accepts a <i>fileName</i> and attempts to extract the contents of this file into a <a href="qstringlistmodel.html">QStringListModel</a>. We display the <a href="qt.html#CursorShape-enum">Qt::WaitCursor</a> when we are populating the <a href="qstringlist.html">QStringList</a>, <tt>words</tt>, and restore the mouse cursor when we are done.</p>
<pre class="cpp"> <span class="type"><a href="qabstractitemmodel.html">QAbstractItemModel</a></span> <span class="operator">*</span>MainWindow<span class="operator">::</span>modelFromFile(<span class="keyword">const</span> <span class="type"><a href="qstring.html">QString</a></span><span class="operator">&</span> fileName)
{
<span class="type"><a href="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="qfile.html">QFile</a></span><span class="operator">::</span>ReadOnly))
<span class="keyword">return</span> <span class="keyword">new</span> <span class="type"><a href="qstringlistmodel.html">QStringListModel</a></span>(completer);
<span class="preprocessor">#ifndef QT_NO_CURSOR</span>
<span class="type"><a href="qapplication.html">QApplication</a></span><span class="operator">::</span>setOverrideCursor(<span class="type"><a href="qcursor.html">QCursor</a></span>(<span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>WaitCursor));
<span class="preprocessor">#endif</span>
<span class="type"><a href="qstringlist.html">QStringList</a></span> words;
<span class="keyword">while</span> (<span class="operator">!</span>file<span class="operator">.</span>atEnd()) {
<span class="type"><a href="qbytearray.html">QByteArray</a></span> line <span class="operator">=</span> file<span class="operator">.</span>readLine();
<span class="keyword">if</span> (<span class="operator">!</span>line<span class="operator">.</span>isEmpty())
words <span class="operator"><</span><span class="operator"><</span> line<span class="operator">.</span>trimmed();
}
<span class="preprocessor">#ifndef QT_NO_CURSOR</span>
<span class="type"><a href="qapplication.html">QApplication</a></span><span class="operator">::</span>restoreOverrideCursor();
<span class="preprocessor">#endif</span>
<span class="keyword">return</span> <span class="keyword">new</span> <span class="type"><a href="qstringlistmodel.html">QStringListModel</a></span>(words<span class="operator">,</span> completer);
}</pre>
<p>The <tt>about()</tt> function provides a brief description about the Custom Completer example.</p>
<pre class="cpp"> <span class="type">void</span> MainWindow<span class="operator">::</span>about()
{
<span class="type"><a href="qmessagebox.html">QMessageBox</a></span><span class="operator">::</span>about(<span class="keyword">this</span><span class="operator">,</span> tr(<span class="string">"About"</span>)<span class="operator">,</span> tr(<span class="string">"This example demonstrates the "</span>
<span class="string">"different features of the QCompleter class."</span>));
}</pre>
<a name="function"></a>
<h2><tt>main()</tt> Function</h2>
<p>The <tt>main()</tt> function instantiates <tt>MainWindow</tt> and invokes the <a href="qwidget.html#show">show()</a> function.</p>
<pre class="cpp"> <span class="type">int</span> main(<span class="type">int</span> argc<span class="operator">,</span> <span class="type">char</span> <span class="operator">*</span>argv<span class="operator">[</span><span class="operator">]</span>)
{
Q_INIT_RESOURCE(customcompleter);
<span class="type"><a href="qapplication.html">QApplication</a></span> app(argc<span class="operator">,</span> argv);
MainWindow window;
window<span class="operator">.</span>show();
<span class="keyword">return</span> app<span class="operator">.</span>exec();
}</pre>
</div>
<!-- @@@tools/customcompleter -->
</div>
</div>
</div>
<div class="ft">
<span></span>
</div>
</div>
<div class="footer">
<p>
<acronym title="Copyright">©</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>
