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<td >Qt 5.9</td><td ><a href="qtwidgets-index.html">Qt Widgets</a></td><td >Custom Completer Example</td></tr></table><table class="buildversion"><tr>
<td id="buildversion" width="100%" align="right">Qt 5.9.4 Reference Documentation</td>
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<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="#main-function"><code>main()</code> Function</a></li>
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<h1 class="title">Custom Completer Example</h1>
<span class="subtitle"></span>
<!-- $$$tools/customcompleter-description -->
<div class="descr"> <a name="details"></a>
<p class="centerAlign"><img src="images/customcompleter-example.png" alt="" /></p><a name="setting-up-the-resource-file"></a>
<h2 id="setting-up-the-resource-file">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 id="textedit-class-definition">TextEdit Class Definition</h2>
<p>The <code>TextEdit</code> class is a subclass of <a href="qtextedit.html">QTextEdit</a> with a custom <code>insertCompletion()</code> slot and it reimplements the <a href="qabstractscrollarea.html#keyPressEvent">keyPressEvent()</a> and the <a href="qwidget.html#focusInEvent">focusInEvent()</a> functions. <code>TextEdit</code> also contains a private function <code>textUnderCursor()</code> and a private instance of <a href="qcompleter.html">QCompleter</a>, <code>c</code>.</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="../qtgui/qkeyevent.html">QKeyEvent</a></span> <span class="operator">*</span>e) override;
<span class="type">void</span> focusInEvent(<span class="type"><a href="../qtgui/qfocusevent.html">QFocusEvent</a></span> <span class="operator">*</span>e) override;
<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="../qtcore/qstring.html">QString</a></span> <span class="operator">&</span>completion);
<span class="keyword">private</span>:
<span class="type"><a href="../qtcore/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 id="textedit-class-implementation">TextEdit Class Implementation</h2>
<p>The constructor for <code>TextEdit</code> constructs a <code>TextEdit</code> with a parent and initializes <code>c</code>. The instructions to use the completer is displayed on the <code>TextEdit</code> object, using the <a href="qtextedit.html#setPlainText">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="../qtgui/qkeysequence.html">QKeySequence</a></span>(<span class="string">"Ctrl+E"</span>)<span class="operator">.</span>toString(<span class="type"><a href="../qtgui/qkeysequence.html">QKeySequence</a></span><span class="operator">::</span>NativeText));
}
</pre>
<p>In addition, <code>TextEdit</code> also includes a default destructor:</p>
<pre class="cpp">
TextEdit<span class="operator">::</span><span class="operator">~</span>TextEdit()
{
}
</pre>
<p>The <code>setCompleter()</code> function accepts a <i>completer</i> and sets it up. We use <code>if (c)</code> to check if <code>c</code> has been initialized. If it has been initialized, the <a href="../qtcore/qobject.html#disconnect-4">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="../qtcore/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="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>CaseInsensitive);
<span class="type"><a href="../qtcore/qobject.html">QObject</a></span><span class="operator">::</span>connect(c<span class="operator">,</span> SIGNAL(activated(<span class="type"><a href="../qtcore/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="../qtcore/qstring.html">QString</a></span>)));
}
</pre>
<p>We then instantiate <code>c</code> with <i>completer</i> and set it as <code>TextEdit</code>'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 <code>insertCompletion()</code> slot.</p>
<p>The <code>completer()</code> function is a getter function that returns <code>c</code>.</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 <code>completion</code> string is then sent to <code>insertCompletion()</code> by the completer's <a href="qcompleter.html#activated">activated()</a> signal.</p>
<p>The <code>insertCompletion()</code> function is responsible for completing the word using a <a href="../qtgui/qtextcursor.html">QTextCursor</a> object, <code>tc</code>. It validates to ensure that the completer's widget is <code>TextEdit</code> before using <code>tc</code> 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="../qtcore/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="../qtgui/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="../qtgui/qtextcursor.html">QTextCursor</a></span><span class="operator">::</span>Left);
tc<span class="operator">.</span>movePosition(<span class="type"><a href="../qtgui/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><code>completion.length()</code> = 6</p>
<p><code>c->completionPrefix().length()</code>=3</p>
<p>The difference between these two values is <code>extra</code>, which is 3. This means that the last three characters from the right, "U", "A", and "L", will be inserted by <code>tc</code>.</p>
<p>The <code>textUnderCursor()</code> function uses a <a href="../qtgui/qtextcursor.html">QTextCursor</a>, <code>tc</code>, to select a word under the cursor and return it.</p>
<pre class="cpp">
<span class="type"><a href="../qtcore/qstring.html">QString</a></span> TextEdit<span class="operator">::</span>textUnderCursor() <span class="keyword">const</span>
{
<span class="type"><a href="../qtgui/qtextcursor.html">QTextCursor</a></span> tc <span class="operator">=</span> textCursor();
tc<span class="operator">.</span>select(<span class="type"><a href="../qtgui/qtextcursor.html">QTextCursor</a></span><span class="operator">::</span>WordUnderCursor);
<span class="keyword">return</span> tc<span class="operator">.</span>selectedText();
}
</pre>
<p>The <code>TextEdit</code> 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="../qtgui/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="../qtcore/qt.html#Key-enum">Qt::Key_Enter</a>, <a href="../qtcore/qt.html#Key-enum">Qt::Key_Return</a>, <a href="../qtcore/qt.html#Key-enum">Qt::Key_Escape</a>, <a href="../qtcore/qt.html#Key-enum">Qt::Key_Tab</a>, and <a href="../qtcore/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="../qtgui/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="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>Key_Enter:
<span class="keyword">case</span> <span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>Key_Return:
<span class="keyword">case</span> <span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>Key_Escape:
<span class="keyword">case</span> <span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>Key_Tab:
<span class="keyword">case</span> <span class="type"><a href="../qtcore/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>;
}
}
bool isShortcut <span class="operator">=</span> ((e<span class="operator">-</span><span class="operator">></span>modifiers() <span class="operator">&</span> <span class="type"><a href="../qtcore/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="../qtcore/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> bool ctrlOrShift <span class="operator">=</span> e<span class="operator">-</span><span class="operator">></span>modifiers() <span class="operator">&</span> (<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>ControlModifier <span class="operator">|</span> <span class="type"><a href="../qtcore/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="../qtcore/qstring.html">QString</a></span> eow(<span class="string">"~!@#$%^&*()_+{}|:\"<>?,./;'[]\\-="</span>); <span class="comment">// end of word</span>
bool 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="../qtcore/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="../qtcore/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="../qtcore/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 id="mainwindow-class-definition">MainWindow Class Definition</h2>
<p>The <code>MainWindow</code> class is a subclass of <a href="qmainwindow.html">QMainWindow</a> and implements a private slot, <code>about()</code>. This class also has two private functions, <code>createMenu()</code> and <code>modelFromFile()</code> as well as private instances of <a href="qcompleter.html">QCompleter</a> and <code>TextEdit</code>.</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="../qtcore/qabstractitemmodel.html">QAbstractItemModel</a></span> <span class="operator">*</span>modelFromFile(<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="qcompleter.html">QCompleter</a></span> <span class="operator">*</span>completer;
TextEdit <span class="operator">*</span>completingTextEdit;
};
</pre>
<a name="mainwindow-class-implementation"></a>
<h2 id="mainwindow-class-implementation">MainWindow Class Implementation</h2>
<p>The constructor constructs a <code>MainWindow</code> with a parent and initializes the <code>completer</code>. It also instantiates a <code>TextEdit</code> and sets its completer. A <a href="../qtcore/qstringlistmodel.html">QStringListModel</a>, obtained from <code>modelFromFile()</code>, is used to populate the <code>completer</code>. The <code>MainWindow</code>'s central widget is set to <code>TextEdit</code> 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="../qtcore/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 <code>createMenu()</code> 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 <code>quit()</code>, <code>about()</code>, and <code>aboutQt()</code> 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 <code>modelFromFile()</code> function accepts a <i>fileName</i> and attempts to extract the contents of this file into a <a href="../qtcore/qstringlistmodel.html">QStringListModel</a>. We display the <a href="../qtcore/qt.html#CursorShape-enum">Qt::WaitCursor</a> when we are populating the <a href="../qtcore/qstringlist.html">QStringList</a>, <code>words</code>, and restore the mouse cursor when we are done.</p>
<pre class="cpp">
<span class="type"><a href="../qtcore/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="../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="keyword">return</span> <span class="keyword">new</span> <span class="type"><a href="../qtcore/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="../qtgui/qcursor.html">QCursor</a></span>(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>WaitCursor));
<span class="preprocessor">#endif</span>
<span class="type"><a href="../qtcore/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="../qtcore/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="../qtcore/qstringlistmodel.html">QStringListModel</a></span>(words<span class="operator">,</span> completer);
}
</pre>
<p>The <code>about()</code> 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="main-function"></a>
<h2 id="main-function"><code>main()</code> Function</h2>
<p>The <code>main()</code> function instantiates <code>MainWindow</code> 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>
<p>Files:</p>
<ul>
<li><a href="qtwidgets-tools-customcompleter-mainwindow-cpp.html">tools/customcompleter/mainwindow.cpp</a></li>
<li><a href="qtwidgets-tools-customcompleter-mainwindow-h.html">tools/customcompleter/mainwindow.h</a></li>
<li><a href="qtwidgets-tools-customcompleter-textedit-cpp.html">tools/customcompleter/textedit.cpp</a></li>
<li><a href="qtwidgets-tools-customcompleter-textedit-h.html">tools/customcompleter/textedit.h</a></li>
<li><a href="qtwidgets-tools-customcompleter-main-cpp.html">tools/customcompleter/main.cpp</a></li>
<li><a href="qtwidgets-tools-customcompleter-customcompleter-pro.html">tools/customcompleter/customcompleter.pro</a></li>
<li><a href="qtwidgets-tools-customcompleter-customcompleter-qrc.html">tools/customcompleter/customcompleter.qrc</a></li>
</ul>
</div>
<!-- @@@tools/customcompleter -->
</div>
</div>
</div>
</div>
</div>
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<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
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distrib
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armv5tl
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media
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core-updates
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