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<td >Qt 5.9</td><td ><a href="qtwidgets-index.html">Qt Widgets</a></td><td >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="#the-resource-file">The Resource File</a></li>
<li class="level1"><a href="#filesystemmodel-class-definition">FileSystemModel Class Definition</a></li>
<li class="level1"><a href="#filesystemmodel-class-implementation">FileSystemModel 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">Completer Example</h1>
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<!-- $$$tools/completer-description -->
<div class="descr"> <a name="details"></a>
<p class="centerAlign"><img src="images/completer-example.png" alt="" /></p><p>This example uses a custom item model, <code>FileSystemModel</code>, and a <a href="qcompleter.html">QCompleter</a> object. <a href="qcompleter.html">QCompleter</a> is a class that provides completions based on an item model. The type of model, the completion mode, and the case sensitivity can be selected using combo boxes.</p>
<a name="the-resource-file"></a>
<h2 id="the-resource-file">The Resource File</h2>
<p>The Completer example requires a resource file in order to store the <i>countries.txt</i> and <i>words.txt</i>. The resource file contains the following code:</p>
<pre class="cpp">
<!DOCTYPE RCC><RCC version="1.0">
<qresource prefix="/">
<file>resources/countries.txt</file>
<file>resources/wordlist.txt</file>
</qresource>
</RCC>
</pre>
<a name="filesystemmodel-class-definition"></a>
<h2 id="filesystemmodel-class-definition">FileSystemModel Class Definition</h2>
<p>The <code>FileSystemModel</code> class is a subclass of <a href="qfilesystemmodel.html">QFileSystemModel</a>, which provides a data model for the local filesystem.</p>
<pre class="cpp">
<span class="keyword">class</span> FileSystemModel : <span class="keyword">public</span> <span class="type"><a href="qfilesystemmodel.html">QFileSystemModel</a></span>
{
<span class="keyword">public</span>:
FileSystemModel(<span class="type"><a href="../qtcore/qobject.html">QObject</a></span> <span class="operator">*</span>parent <span class="operator">=</span> <span class="number">0</span>);
<span class="type"><a href="../qtcore/qvariant.html">QVariant</a></span> data(<span class="keyword">const</span> <span class="type"><a href="../qtcore/qmodelindex.html">QModelIndex</a></span> <span class="operator">&</span>index<span class="operator">,</span> <span class="type">int</span> role <span class="operator">=</span> <span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>DisplayRole) <span class="keyword">const</span> override;
};
</pre>
<p>This class only has a constructor and a <code>data()</code> function as it is only created to enable <code>data()</code> to return the entire file path for the display role, unlike <a href="qfilesystemmodel.html">QFileSystemModel</a>'s <code>data()</code> function that only returns the folder and not the drive label. This is further explained in <code>FileSystemModel</code>'s implementation.</p>
<a name="filesystemmodel-class-implementation"></a>
<h2 id="filesystemmodel-class-implementation">FileSystemModel Class Implementation</h2>
<p>The constructor for the <code>FileSystemModel</code> class is used to pass <i>parent</i> to <a href="qfilesystemmodel.html">QFileSystemModel</a>.</p>
<pre class="cpp">
FileSystemModel<span class="operator">::</span>FileSystemModel(<span class="type"><a href="../qtcore/qobject.html">QObject</a></span> <span class="operator">*</span>parent)
: <span class="type"><a href="qfilesystemmodel.html">QFileSystemModel</a></span>(parent)
{
}
</pre>
<p>As mentioned earlier, the <code>data()</code> function is reimplemented in order to get it to return the entire file parth for the display role. For example, with a <a href="qfilesystemmodel.html">QFileSystemModel</a>, you will see "Program Files" in the view. However, with <code>FileSystemModel</code>, you will see "C:\Program Files".</p>
<pre class="cpp">
<span class="type"><a href="../qtcore/qvariant.html">QVariant</a></span> FileSystemModel<span class="operator">::</span>data(<span class="keyword">const</span> <span class="type"><a href="../qtcore/qmodelindex.html">QModelIndex</a></span> <span class="operator">&</span>index<span class="operator">,</span> <span class="type">int</span> role) <span class="keyword">const</span>
{
<span class="keyword">if</span> (role <span class="operator">=</span><span class="operator">=</span> <span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>DisplayRole <span class="operator">&</span><span class="operator">&</span> index<span class="operator">.</span>column() <span class="operator">=</span><span class="operator">=</span> <span class="number">0</span>) {
<span class="type"><a href="../qtcore/qstring.html">QString</a></span> path <span class="operator">=</span> <span class="type"><a href="../qtcore/qdir.html">QDir</a></span><span class="operator">::</span>toNativeSeparators(filePath(index));
<span class="keyword">if</span> (path<span class="operator">.</span>endsWith(<span class="type"><a href="../qtcore/qdir.html">QDir</a></span><span class="operator">::</span>separator()))
path<span class="operator">.</span>chop(<span class="number">1</span>);
<span class="keyword">return</span> path;
}
<span class="keyword">return</span> <span class="type"><a href="qfilesystemmodel.html">QFileSystemModel</a></span><span class="operator">::</span>data(index<span class="operator">,</span> role);
}
</pre>
<p>The screenshots below illustrate this difference:</p>
<div class="table"><table class="generic">
<tr valign="top" class="odd"><td ><img src="images/completer-example-qdirmodel.png" alt="" /></td><td ><img src="images/completer-example-dirmodel.png" alt="" /></td></tr>
</table></div>
<p>The <a href="../qtcore/qt.html#ItemDataRole-enum">Qt::EditRole</a>, which <a href="qcompleter.html">QCompleter</a> uses to look for matches, is left unchanged.</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 five private slots - <code>about()</code>, <code>changeCase()</code>, <code>changeMode()</code>, <code>changeModel()</code>, and <code>changeMaxVisible()</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="type">void</span> changeCase(<span class="type">int</span>);
<span class="type">void</span> changeMode(<span class="type">int</span>);
<span class="type">void</span> changeModel();
<span class="type">void</span> changeMaxVisible(<span class="type">int</span>);
</pre>
<p>Within the <code>MainWindow</code> class, we have two private functions: <code>createMenu()</code> and <code>modelFromFile()</code>. We also declare the private widgets needed - three <a href="qcombobox.html">QComboBox</a> objects, a <a href="qcheckbox.html">QCheckBox</a>, a <a href="qcompleter.html">QCompleter</a>, a <a href="qlabel.html">QLabel</a>, and a <a href="qlineedit.html">QLineEdit</a>.</p>
<pre class="cpp">
<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="qcombobox.html">QComboBox</a></span> <span class="operator">*</span>caseCombo;
<span class="type"><a href="qcombobox.html">QComboBox</a></span> <span class="operator">*</span>modeCombo;
<span class="type"><a href="qcombobox.html">QComboBox</a></span> <span class="operator">*</span>modelCombo;
<span class="type"><a href="qspinbox.html">QSpinBox</a></span> <span class="operator">*</span>maxVisibleSpinBox;
<span class="type"><a href="qcheckbox.html">QCheckBox</a></span> <span class="operator">*</span>wrapCheckBox;
<span class="type"><a href="qcompleter.html">QCompleter</a></span> <span class="operator">*</span>completer;
<span class="type"><a href="qlabel.html">QLabel</a></span> <span class="operator">*</span>contentsLabel;
<span class="type"><a href="qlineedit.html">QLineEdit</a></span> <span class="operator">*</span>lineEdit;
};
</pre>
<a name="mainwindow-class-implementation"></a>
<h2 id="mainwindow-class-implementation">MainWindow Class Implementation</h2>
<p>The constructor of <code>MainWindow</code> constructs a <code>MainWindow</code> with a parent widget and initializes the private members. The <code>createMenu()</code> function is then invoked.</p>
<p>We set up three <a href="qcombobox.html">QComboBox</a> objects, <code>modelComb</code>, <code>modeCombo</code> and <code>caseCombo</code>. By default, the <code>modelCombo</code> is set to <a href="qfilesystemmodel.html">QFileSystemModel</a>, the <code>modeCombo</code> is set to "Filtered Popup" and the <code>caseCombo</code> is set to "Case Insensitive".</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>)<span class="operator">,</span> lineEdit(<span class="number">0</span>)
{
createMenu();
<span class="type"><a href="qwidget.html">QWidget</a></span> <span class="operator">*</span>centralWidget <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qwidget.html">QWidget</a></span>;
<span class="type"><a href="qlabel.html">QLabel</a></span> <span class="operator">*</span>modelLabel <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qlabel.html">QLabel</a></span>;
modelLabel<span class="operator">-</span><span class="operator">></span>setText(tr(<span class="string">"Model"</span>));
modelCombo <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qcombobox.html">QComboBox</a></span>;
modelCombo<span class="operator">-</span><span class="operator">></span>addItem(tr(<span class="string">"QFileSytemModel"</span>));
modelCombo<span class="operator">-</span><span class="operator">></span>addItem(tr(<span class="string">"QFileSytemModel that shows full path"</span>));
modelCombo<span class="operator">-</span><span class="operator">></span>addItem(tr(<span class="string">"Country list"</span>));
modelCombo<span class="operator">-</span><span class="operator">></span>addItem(tr(<span class="string">"Word list"</span>));
modelCombo<span class="operator">-</span><span class="operator">></span>setCurrentIndex(<span class="number">0</span>);
<span class="type"><a href="qlabel.html">QLabel</a></span> <span class="operator">*</span>modeLabel <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qlabel.html">QLabel</a></span>;
modeLabel<span class="operator">-</span><span class="operator">></span>setText(tr(<span class="string">"Completion Mode"</span>));
modeCombo <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qcombobox.html">QComboBox</a></span>;
modeCombo<span class="operator">-</span><span class="operator">></span>addItem(tr(<span class="string">"Inline"</span>));
modeCombo<span class="operator">-</span><span class="operator">></span>addItem(tr(<span class="string">"Filtered Popup"</span>));
modeCombo<span class="operator">-</span><span class="operator">></span>addItem(tr(<span class="string">"Unfiltered Popup"</span>));
modeCombo<span class="operator">-</span><span class="operator">></span>setCurrentIndex(<span class="number">1</span>);
<span class="type"><a href="qlabel.html">QLabel</a></span> <span class="operator">*</span>caseLabel <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qlabel.html">QLabel</a></span>;
caseLabel<span class="operator">-</span><span class="operator">></span>setText(tr(<span class="string">"Case Sensitivity"</span>));
caseCombo <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qcombobox.html">QComboBox</a></span>;
caseCombo<span class="operator">-</span><span class="operator">></span>addItem(tr(<span class="string">"Case Insensitive"</span>));
caseCombo<span class="operator">-</span><span class="operator">></span>addItem(tr(<span class="string">"Case Sensitive"</span>));
caseCombo<span class="operator">-</span><span class="operator">></span>setCurrentIndex(<span class="number">0</span>);
</pre>
<p>The <code>maxVisibleSpinBox</code> is created and determines the number of visible item in the completer</p>
<p>The <code>wrapCheckBox</code> is then set up. This <code>checkBox</code> determines if the <code>completer</code>'s <a href="qcompleter.html#wrapAround-prop">setWrapAround()</a> property is enabled or disabled.</p>
<pre class="cpp">
<span class="type"><a href="qlabel.html">QLabel</a></span> <span class="operator">*</span>maxVisibleLabel <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qlabel.html">QLabel</a></span>;
maxVisibleLabel<span class="operator">-</span><span class="operator">></span>setText(tr(<span class="string">"Max Visible Items"</span>));
maxVisibleSpinBox <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qspinbox.html">QSpinBox</a></span>;
maxVisibleSpinBox<span class="operator">-</span><span class="operator">></span>setRange(<span class="number">3</span><span class="operator">,</span><span class="number">25</span>);
maxVisibleSpinBox<span class="operator">-</span><span class="operator">></span>setValue(<span class="number">10</span>);
wrapCheckBox <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qcheckbox.html">QCheckBox</a></span>;
wrapCheckBox<span class="operator">-</span><span class="operator">></span>setText(tr(<span class="string">"Wrap around completions"</span>));
wrapCheckBox<span class="operator">-</span><span class="operator">></span>setChecked(<span class="keyword">true</span>);
</pre>
<p>We instantiate <code>contentsLabel</code> and set its size policy to <a href="qsizepolicy.html#Policy-enum">fixed</a>. The combo boxes' <a href="qcombobox.html#activated">activated()</a> signals are then connected to their respective slots.</p>
<pre class="cpp">
contentsLabel <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qlabel.html">QLabel</a></span>;
contentsLabel<span class="operator">-</span><span class="operator">></span>setSizePolicy(<span class="type"><a href="qsizepolicy.html">QSizePolicy</a></span><span class="operator">::</span>Fixed<span class="operator">,</span> <span class="type"><a href="qsizepolicy.html">QSizePolicy</a></span><span class="operator">::</span>Fixed);
connect(modelCombo<span class="operator">,</span> SIGNAL(activated(<span class="type">int</span>))<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> SLOT(changeModel()));
connect(modeCombo<span class="operator">,</span> SIGNAL(activated(<span class="type">int</span>))<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> SLOT(changeMode(<span class="type">int</span>)));
connect(caseCombo<span class="operator">,</span> SIGNAL(activated(<span class="type">int</span>))<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> SLOT(changeCase(<span class="type">int</span>)));
connect(maxVisibleSpinBox<span class="operator">,</span> SIGNAL(valueChanged(<span class="type">int</span>))<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> SLOT(changeMaxVisible(<span class="type">int</span>)));
</pre>
<p>The <code>lineEdit</code> is set up and then we arrange all the widgets using a <a href="qgridlayout.html">QGridLayout</a>. The <code>changeModel()</code> function is called, to initialize the <code>completer</code>.</p>
<pre class="cpp">
lineEdit <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qlineedit.html">QLineEdit</a></span>;
<span class="type"><a href="qgridlayout.html">QGridLayout</a></span> <span class="operator">*</span>layout <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qgridlayout.html">QGridLayout</a></span>;
layout<span class="operator">-</span><span class="operator">></span>addWidget(modelLabel<span class="operator">,</span> <span class="number">0</span><span class="operator">,</span> <span class="number">0</span>); layout<span class="operator">-</span><span class="operator">></span>addWidget(modelCombo<span class="operator">,</span> <span class="number">0</span><span class="operator">,</span> <span class="number">1</span>);
layout<span class="operator">-</span><span class="operator">></span>addWidget(modeLabel<span class="operator">,</span> <span class="number">1</span><span class="operator">,</span> <span class="number">0</span>); layout<span class="operator">-</span><span class="operator">></span>addWidget(modeCombo<span class="operator">,</span> <span class="number">1</span><span class="operator">,</span> <span class="number">1</span>);
layout<span class="operator">-</span><span class="operator">></span>addWidget(caseLabel<span class="operator">,</span> <span class="number">2</span><span class="operator">,</span> <span class="number">0</span>); layout<span class="operator">-</span><span class="operator">></span>addWidget(caseCombo<span class="operator">,</span> <span class="number">2</span><span class="operator">,</span> <span class="number">1</span>);
layout<span class="operator">-</span><span class="operator">></span>addWidget(maxVisibleLabel<span class="operator">,</span> <span class="number">3</span><span class="operator">,</span> <span class="number">0</span>); layout<span class="operator">-</span><span class="operator">></span>addWidget(maxVisibleSpinBox<span class="operator">,</span> <span class="number">3</span><span class="operator">,</span> <span class="number">1</span>);
layout<span class="operator">-</span><span class="operator">></span>addWidget(wrapCheckBox<span class="operator">,</span> <span class="number">4</span><span class="operator">,</span> <span class="number">0</span>);
layout<span class="operator">-</span><span class="operator">></span>addWidget(contentsLabel<span class="operator">,</span> <span class="number">5</span><span class="operator">,</span> <span class="number">0</span><span class="operator">,</span> <span class="number">1</span><span class="operator">,</span> <span class="number">2</span>);
layout<span class="operator">-</span><span class="operator">></span>addWidget(lineEdit<span class="operator">,</span> <span class="number">6</span><span class="operator">,</span> <span class="number">0</span><span class="operator">,</span> <span class="number">1</span><span class="operator">,</span> <span class="number">2</span>);
centralWidget<span class="operator">-</span><span class="operator">></span>setLayout(layout);
setCentralWidget(centralWidget);
changeModel();
setWindowTitle(tr(<span class="string">"Completer"</span>));
lineEdit<span class="operator">-</span><span class="operator">></span>setFocus();
}
</pre>
<p>The <code>createMenu()</code> function is used to instantiate the <a href="qaction.html">QAction</a> objects needed to fill the <code>fileMenu</code> and <code>helpMenu</code>. The actions' <a href="qaction.html#triggered">triggered()</a> signals are connected to their respective slots.</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 the <i>fileName</i> of a file and processes it depending on its contents.</p>
<p>We first validate the <code>file</code> to ensure that it can be opened in <a href="../qtcore/qiodevice.html#OpenModeFlag-enum">QFile::ReadOnly</a> mode. If this is unsuccessful, the function returns an empty <a href="../qtcore/qstringlistmodel.html">QStringListModel</a>.</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);
</pre>
<p>The mouse cursor is then overridden with <a href="../qtcore/qt.html#CursorShape-enum">Qt::WaitCursor</a> before we fill a <a href="../qtcore/qstringlist.html">QStringList</a> object, <code>words</code>, with the contents of <code>file</code>. Once this is done, we restore the mouse cursor.</p>
<pre class="cpp">
<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>
</pre>
<p>As mentioned earlier, the resources file contains two files - <i>countries.txt</i> and <i>words.txt</i>. If the <code>file</code> read is <i>words.txt</i>, we return a <a href="../qtcore/qstringlistmodel.html">QStringListModel</a> with <code>words</code> as its <a href="../qtcore/qstringlist.html">QStringList</a> and <code>completer</code> as its parent.</p>
<pre class="cpp">
<span class="keyword">if</span> (<span class="operator">!</span>fileName<span class="operator">.</span>contains(QLatin1String(<span class="string">"countries.txt"</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>If the <code>file</code> read is <i>countries.txt</i>, then we require a <a href="../qtgui/qstandarditemmodel.html">QStandardItemModel</a> with <code>words.count()</code> rows, 2 columns, and <code>completer</code> as its parent.</p>
<pre class="cpp">
<span class="type"><a href="../qtgui/qstandarditemmodel.html">QStandardItemModel</a></span> <span class="operator">*</span>m <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="../qtgui/qstandarditemmodel.html">QStandardItemModel</a></span>(words<span class="operator">.</span>count()<span class="operator">,</span> <span class="number">2</span><span class="operator">,</span> completer);
</pre>
<p>A standard line in <i>countries.txt</i> is:</p>
<blockquote><p>Norway NO</p>
</blockquote>
<p>Hence, to populate the <a href="../qtgui/qstandarditemmodel.html">QStandardItemModel</a> object, <code>m</code>, we have to split the country name and its symbol. Once this is done, we return <code>m</code>.</p>
<pre class="cpp">
<span class="keyword">for</span> (<span class="type">int</span> i <span class="operator">=</span> <span class="number">0</span>; i <span class="operator"><</span> words<span class="operator">.</span>count(); <span class="operator">+</span><span class="operator">+</span>i) {
<span class="type"><a href="../qtcore/qmodelindex.html">QModelIndex</a></span> countryIdx <span class="operator">=</span> m<span class="operator">-</span><span class="operator">></span>index(i<span class="operator">,</span> <span class="number">0</span>);
<span class="type"><a href="../qtcore/qmodelindex.html">QModelIndex</a></span> symbolIdx <span class="operator">=</span> m<span class="operator">-</span><span class="operator">></span>index(i<span class="operator">,</span> <span class="number">1</span>);
<span class="type"><a href="../qtcore/qstring.html">QString</a></span> country <span class="operator">=</span> words<span class="operator">[</span>i<span class="operator">]</span><span class="operator">.</span>mid(<span class="number">0</span><span class="operator">,</span> words<span class="operator">[</span>i<span class="operator">]</span><span class="operator">.</span>length() <span class="operator">-</span> <span class="number">2</span>)<span class="operator">.</span>trimmed();
<span class="type"><a href="../qtcore/qstring.html">QString</a></span> symbol <span class="operator">=</span> words<span class="operator">[</span>i<span class="operator">]</span><span class="operator">.</span>right(<span class="number">2</span>);
m<span class="operator">-</span><span class="operator">></span>setData(countryIdx<span class="operator">,</span> country);
m<span class="operator">-</span><span class="operator">></span>setData(symbolIdx<span class="operator">,</span> symbol);
}
<span class="keyword">return</span> m;
}
</pre>
<p>The <code>changeMode()</code> function sets the <code>completer</code>'s mode, depending on the value of <code>index</code>.</p>
<pre class="cpp">
<span class="type">void</span> MainWindow<span class="operator">::</span>changeMode(<span class="type">int</span> index)
{
<span class="type"><a href="qcompleter.html">QCompleter</a></span><span class="operator">::</span>CompletionMode mode;
<span class="keyword">if</span> (index <span class="operator">=</span><span class="operator">=</span> <span class="number">0</span>)
mode <span class="operator">=</span> <span class="type"><a href="qcompleter.html">QCompleter</a></span><span class="operator">::</span>InlineCompletion;
<span class="keyword">else</span> <span class="keyword">if</span> (index <span class="operator">=</span><span class="operator">=</span> <span class="number">1</span>)
mode <span class="operator">=</span> <span class="type"><a href="qcompleter.html">QCompleter</a></span><span class="operator">::</span>PopupCompletion;
<span class="keyword">else</span>
mode <span class="operator">=</span> <span class="type"><a href="qcompleter.html">QCompleter</a></span><span class="operator">::</span>UnfilteredPopupCompletion;
completer<span class="operator">-</span><span class="operator">></span>setCompletionMode(mode);
}
</pre>
<p>The <code>changeModel()</code> function changes the item model used based on the model selected by the user.</p>
<p>A <code>switch</code> statement is used to change the item model based on the index of <code>modelCombo</code>. If <code>case</code> is 0, we use an unsorted <a href="qfilesystemmodel.html">QFileSystemModel</a>, providing us with a file path excluding the drive label.</p>
<pre class="cpp">
<span class="type">void</span> MainWindow<span class="operator">::</span>changeModel()
{
<span class="keyword">delete</span> completer;
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>setMaxVisibleItems(maxVisibleSpinBox<span class="operator">-</span><span class="operator">></span>value());
<span class="keyword">switch</span> (modelCombo<span class="operator">-</span><span class="operator">></span>currentIndex()) {
<span class="keyword">default</span>:
<span class="keyword">case</span> <span class="number">0</span>:
{ <span class="comment">// Unsorted QFileSystemModel</span>
<span class="type"><a href="qfilesystemmodel.html">QFileSystemModel</a></span> <span class="operator">*</span>fsModel <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qfilesystemmodel.html">QFileSystemModel</a></span>(completer);
fsModel<span class="operator">-</span><span class="operator">></span>setRootPath(<span class="string">""</span>);
completer<span class="operator">-</span><span class="operator">></span>setModel(fsModel);
contentsLabel<span class="operator">-</span><span class="operator">></span>setText(tr(<span class="string">"Enter file path"</span>));
}
<span class="keyword">break</span>;
</pre>
<p>Note that we create the model with <code>completer</code> as the parent as this allows us to replace the model with a new model. The <code>completer</code> will ensure that the old one is deleted the moment a new model is assigned to it.</p>
<p>If <code>case</code> is 1, we use the <code>DirModel</code> we defined earlier, resulting in full paths for the files.</p>
<pre class="cpp">
<span class="keyword">case</span> <span class="number">1</span>:
{ <span class="comment">// FileSystemModel that shows full paths</span>
FileSystemModel <span class="operator">*</span>fsModel <span class="operator">=</span> <span class="keyword">new</span> FileSystemModel(completer);
completer<span class="operator">-</span><span class="operator">></span>setModel(fsModel);
fsModel<span class="operator">-</span><span class="operator">></span>setRootPath(<span class="string">""</span>);
contentsLabel<span class="operator">-</span><span class="operator">></span>setText(tr(<span class="string">"Enter file path"</span>));
}
<span class="keyword">break</span>;
</pre>
<p>When <code>case</code> is 2, we attempt to complete names of countries. This requires a <a href="qtreeview.html">QTreeView</a> object, <code>treeView</code>. The country names are extracted from <i>countries.txt</i> and set the popup used to display completions to <code>treeView</code>.</p>
<pre class="cpp">
<span class="keyword">case</span> <span class="number">2</span>:
{ <span class="comment">// Country List</span>
completer<span class="operator">-</span><span class="operator">></span>setModel(modelFromFile(<span class="string">":/resources/countries.txt"</span>));
<span class="type"><a href="qtreeview.html">QTreeView</a></span> <span class="operator">*</span>treeView <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qtreeview.html">QTreeView</a></span>;
completer<span class="operator">-</span><span class="operator">></span>setPopup(treeView);
treeView<span class="operator">-</span><span class="operator">></span>setRootIsDecorated(<span class="keyword">false</span>);
treeView<span class="operator">-</span><span class="operator">></span>header()<span class="operator">-</span><span class="operator">></span>hide();
treeView<span class="operator">-</span><span class="operator">></span>header()<span class="operator">-</span><span class="operator">></span>setStretchLastSection(<span class="keyword">false</span>);
treeView<span class="operator">-</span><span class="operator">></span>header()<span class="operator">-</span><span class="operator">></span>setSectionResizeMode(<span class="number">0</span><span class="operator">,</span> <span class="type"><a href="qheaderview.html">QHeaderView</a></span><span class="operator">::</span>Stretch);
treeView<span class="operator">-</span><span class="operator">></span>header()<span class="operator">-</span><span class="operator">></span>setSectionResizeMode(<span class="number">1</span><span class="operator">,</span> <span class="type"><a href="qheaderview.html">QHeaderView</a></span><span class="operator">::</span>ResizeToContents);
contentsLabel<span class="operator">-</span><span class="operator">></span>setText(tr(<span class="string">"Enter name of your country"</span>));
}
<span class="keyword">break</span>;
</pre>
<p>The screenshot below shows the Completer with the country list model.</p>
<p class="centerAlign"><img src="images/completer-example-country.png" alt="" /></p><p>If <code>case</code> is 3, we attempt to complete words. This is done using a <a href="../qtcore/qstringlistmodel.html">QStringListModel</a> that contains data extracted from <i>words.txt</i>. The model is sorted <a href="qcompleter.html#ModelSorting-enum">case insensitively</a>.</p>
<p>The screenshot below shows the Completer with the word list model.</p>
<p class="centerAlign"><img src="images/completer-example-word.png" alt="" /></p><p>Once the model type is selected, we call the <code>changeMode()</code> function and the <code>changeCase()</code> function and set the wrap option accordingly. The <code>wrapCheckBox</code>'s <a href="qabstractbutton.html#clicked">clicked()</a> signal is connected to the <code>completer</code>'s <a href="qcompleter.html#wrapAround-prop">setWrapAround()</a> slot.</p>
<pre class="cpp">
<span class="keyword">case</span> <span class="number">3</span>:
{ <span class="comment">// Word list</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);
contentsLabel<span class="operator">-</span><span class="operator">></span>setText(tr(<span class="string">"Enter a word"</span>));
}
<span class="keyword">break</span>;
}
changeMode(modeCombo<span class="operator">-</span><span class="operator">></span>currentIndex());
changeCase(caseCombo<span class="operator">-</span><span class="operator">></span>currentIndex());
completer<span class="operator">-</span><span class="operator">></span>setWrapAround(wrapCheckBox<span class="operator">-</span><span class="operator">></span>isChecked());
lineEdit<span class="operator">-</span><span class="operator">></span>setCompleter(completer);
connect(wrapCheckBox<span class="operator">,</span> SIGNAL(clicked(bool))<span class="operator">,</span> completer<span class="operator">,</span> SLOT(setWrapAround(bool)));
}
</pre>
<p>The <code>changeMaxVisible()</code> update the maximum number of visible items in the completer.</p>
<pre class="cpp">
<span class="type">void</span> MainWindow<span class="operator">::</span>changeMaxVisible(<span class="type">int</span> max)
{
completer<span class="operator">-</span><span class="operator">></span>setMaxVisibleItems(max);
}
</pre>
<p>The <code>about()</code> function provides a brief description about the 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 <a href="qapplication.html">QApplication</a> and <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(completer);
<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-completer-fsmodel-cpp.html">tools/completer/fsmodel.cpp</a></li>
<li><a href="qtwidgets-tools-completer-fsmodel-h.html">tools/completer/fsmodel.h</a></li>
<li><a href="qtwidgets-tools-completer-mainwindow-cpp.html">tools/completer/mainwindow.cpp</a></li>
<li><a href="qtwidgets-tools-completer-mainwindow-h.html">tools/completer/mainwindow.h</a></li>
<li><a href="qtwidgets-tools-completer-main-cpp.html">tools/completer/main.cpp</a></li>
<li><a href="qtwidgets-tools-completer-completer-pro.html">tools/completer/completer.pro</a></li>
<li><a href="qtwidgets-tools-completer-completer-qrc.html">tools/completer/completer.qrc</a></li>
</ul>
</div>
<!-- @@@tools/completer -->
</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>
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