<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE html> <html lang="en"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <!-- qvalidator.cpp --> <title>QValidator Class | Qt GUI 5.11</title> <link rel="stylesheet" type="text/css" href="style/offline-simple.css" /> <script type="text/javascript"> document.getElementsByTagName("link").item(0).setAttribute("href", "style/offline.css"); // loading style sheet breaks anchors that were jumped to before // so force jumping to anchor again setTimeout(function() { var anchor = location.hash; // need to jump to different anchor first (e.g. none) location.hash = "#"; setTimeout(function() { location.hash = anchor; }, 0); }, 0); </script> </head> <body> <div class="header" id="qtdocheader"> <div class="main"> <div class="main-rounded"> <div class="navigationbar"> <table><tr> <td ><a href="../qtdoc/index.html">Qt 5.11</a></td><td ><a href="qtgui-index.html">Qt GUI</a></td><td ><a href="qtgui-module.html">C++ Classes</a></td><td >QValidator</td></tr></table><table class="buildversion"><tr> <td id="buildversion" width="100%" align="right">Qt 5.11.2 Reference Documentation</td> </tr></table> </div> </div> <div class="content"> <div class="line"> <div class="content mainContent"> <div class="sidebar"> <div class="toc"> <h3><a name="toc">Contents</a></h3> <ul> <li class="level1"><a href="#public-types">Public Types</a></li> <li class="level1"><a href="#public-functions">Public Functions</a></li> <li class="level1"><a href="#signals">Signals</a></li> <li class="level1"><a href="#details">Detailed Description</a></li> </ul> </div> <div class="sidebar-content" id="sidebar-content"></div></div> <h1 class="title">QValidator Class</h1> <!-- $$$QValidator-brief --> <p>The <a href="qvalidator.html">QValidator</a> class provides validation of input text. <a href="#details">More...</a></p> <!-- @@@QValidator --> <div class="table"><table class="alignedsummary"> <tr><td class="memItemLeft rightAlign topAlign"> Header:</td><td class="memItemRight bottomAlign"> <span class="preprocessor">#include <QValidator></span> </td></tr><tr><td class="memItemLeft rightAlign topAlign"> qmake:</td><td class="memItemRight bottomAlign"> QT += gui</td></tr><tr><td class="memItemLeft rightAlign topAlign"> Inherits:</td><td class="memItemRight bottomAlign"> <a href="../qtcore/qobject.html">QObject</a></td></tr><tr><td class="memItemLeft rightAlign topAlign"> Inherited By:</td><td class="memItemRight bottomAlign"> <p><a href="qdoublevalidator.html">QDoubleValidator</a>, <a href="qintvalidator.html">QIntValidator</a>, <a href="qregexpvalidator.html">QRegExpValidator</a>, and <a href="qregularexpressionvalidator.html">QRegularExpressionValidator</a></p> </td></tr></table></div><ul> <li><a href="qvalidator-members.html">List of all members, including inherited members</a></li> </ul> <a name="public-types"></a> <h2 id="public-types">Public Types</h2> <div class="table"><table class="alignedsummary"> <tr><td class="memItemLeft rightAlign topAlign"> enum </td><td class="memItemRight bottomAlign"><b><a href="qvalidator.html#State-enum">State</a></b> { Invalid, Intermediate, Acceptable }</td></tr> </table></div> <a name="public-functions"></a> <h2 id="public-functions">Public Functions</h2> <div class="table"><table class="alignedsummary"> <tr><td class="memItemLeft rightAlign topAlign"> </td><td class="memItemRight bottomAlign"><b><a href="qvalidator.html#QValidator">QValidator</a></b>(QObject *<i>parent</i> = nullptr)</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> virtual </td><td class="memItemRight bottomAlign"><b><a href="qvalidator.html#dtor.QValidator">~QValidator</a></b>()</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> virtual void </td><td class="memItemRight bottomAlign"><b><a href="qvalidator.html#fixup">fixup</a></b>(QString &<i>input</i>) const</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> QLocale </td><td class="memItemRight bottomAlign"><b><a href="qvalidator.html#locale">locale</a></b>() const</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qvalidator.html#setLocale">setLocale</a></b>(const QLocale &<i>locale</i>)</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> virtual QValidator::State </td><td class="memItemRight bottomAlign"><b><a href="qvalidator.html#validate">validate</a></b>(QString &<i>input</i>, int &<i>pos</i>) const = 0</td></tr> </table></div> <ul> <li class="fn">34 public functions inherited from <a href="../qtcore/qobject.html#public-functions">QObject</a></li> </ul> <a name="signals"></a> <h2 id="signals">Signals</h2> <div class="table"><table class="alignedsummary"> <tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qvalidator.html#changed">changed</a></b>()</td></tr> </table></div> <ul> <li class="fn">2 signals inherited from <a href="../qtcore/qobject.html#signals">QObject</a></li> </ul> <h3>Additional Inherited Members</h3> <ul> <li class="fn">1 property inherited from <a href="../qtcore/qobject.html#properties">QObject</a></li> <li class="fn">1 public slot inherited from <a href="../qtcore/qobject.html#public-slots">QObject</a></li> <li class="fn">1 public variable inherited from <a href="../qtcore/qobject.html#public-variables">QObject</a></li> <li class="fn">10 static public members inherited from <a href="../qtcore/qobject.html#static-public-members">QObject</a></li> <li class="fn">9 protected functions inherited from <a href="../qtcore/qobject.html#protected-functions">QObject</a></li> <li class="fn">2 protected variables inherited from <a href="../qtcore/qobject.html#protected-variables">QObject</a></li> </ul> <a name="details"></a> <!-- $$$QValidator-description --> <div class="descr"> <h2 id="details">Detailed Description</h2> <p>The <a href="qvalidator.html">QValidator</a> class provides validation of input text.</p> <p>The class itself is abstract. Two subclasses, <a href="qintvalidator.html">QIntValidator</a> and <a href="qdoublevalidator.html">QDoubleValidator</a>, provide basic numeric-range checking, and <a href="qregexpvalidator.html">QRegExpValidator</a> provides general checking using a custom regular expression.</p> <p>If the built-in validators aren't sufficient, you can subclass <a href="qvalidator.html">QValidator</a>. The class has two virtual functions: <a href="qvalidator.html#validate">validate</a>() and <a href="qvalidator.html#fixup">fixup</a>().</p> <p><a href="qvalidator.html#validate">validate</a>() must be implemented by every subclass. It returns <a href="qvalidator.html#State-enum">Invalid</a>, <a href="qvalidator.html#State-enum">Intermediate</a> or <a href="qvalidator.html#State-enum">Acceptable</a> depending on whether its argument is valid (for the subclass's definition of valid).</p> <p>These three states require some explanation. An <a href="qvalidator.html#State-enum">Invalid</a> string is <i>clearly</i> invalid. <a href="qvalidator.html#State-enum">Intermediate</a> is less obvious: the concept of validity is difficult to apply when the string is incomplete (still being edited). <a href="qvalidator.html">QValidator</a> defines <a href="qvalidator.html#State-enum">Intermediate</a> as the property of a string that is neither clearly invalid nor acceptable as a final result. <a href="qvalidator.html#State-enum">Acceptable</a> means that the string is acceptable as a final result. One might say that any string that is a plausible intermediate state during entry of an <a href="qvalidator.html#State-enum">Acceptable</a> string is <a href="qvalidator.html#State-enum">Intermediate</a>.</p> <p>Here are some examples:</p> <ul> <li>For a line edit that accepts integers from 10 to 1000 inclusive, 42 and 123 are <a href="qvalidator.html#State-enum">Acceptable</a>, the empty string and 5 are <a href="qvalidator.html#State-enum">Intermediate</a>, and "asdf" and 1114 is <a href="qvalidator.html#State-enum">Invalid</a>.</li> <li>For an editable combobox that accepts URLs, any well-formed URL is <a href="qvalidator.html#State-enum">Acceptable</a>, "http://example.com/," is <a href="qvalidator.html#State-enum">Intermediate</a> (it might be a cut and paste action that accidentally took in a comma at the end), the empty string is <a href="qvalidator.html#State-enum">Intermediate</a> (the user might select and delete all of the text in preparation for entering a new URL) and "http:///./" is <a href="qvalidator.html#State-enum">Invalid</a>.</li> <li>For a spin box that accepts lengths, "11cm" and "1in" are <a href="qvalidator.html#State-enum">Acceptable</a>, "11" and the empty string are <a href="qvalidator.html#State-enum">Intermediate</a>, and "http://example.com" and "hour" are <a href="qvalidator.html#State-enum">Invalid</a>.</li> </ul> <p><a href="qvalidator.html#fixup">fixup</a>() is provided for validators that can repair some user errors. The default implementation does nothing. <a href="../qtwidgets/qlineedit.html">QLineEdit</a>, for example, will call <a href="qvalidator.html#fixup">fixup</a>() if the user presses Enter (or Return) and the content is not currently valid. This allows the <a href="qvalidator.html#fixup">fixup</a>() function the opportunity of performing some magic to make an <a href="qvalidator.html#State-enum">Invalid</a> string <a href="qvalidator.html#State-enum">Acceptable</a>.</p> <p>A validator has a locale, set with <a href="qvalidator.html#setLocale">setLocale</a>(). It is typically used to parse localized data. For example, <a href="qintvalidator.html">QIntValidator</a> and <a href="qdoublevalidator.html">QDoubleValidator</a> use it to parse localized representations of integers and doubles.</p> <p><a href="qvalidator.html">QValidator</a> is typically used with <a href="../qtwidgets/qlineedit.html">QLineEdit</a>, <a href="../qtwidgets/qspinbox.html">QSpinBox</a> and <a href="../qtwidgets/qcombobox.html">QComboBox</a>.</p> </div> <p><b>See also </b><a href="qintvalidator.html">QIntValidator</a>, <a href="qdoublevalidator.html">QDoubleValidator</a>, <a href="qregexpvalidator.html">QRegExpValidator</a>, and <a href="../qtwidgets/qtwidgets-widgets-lineedits-example.html">Line Edits Example</a>.</p> <!-- @@@QValidator --> <div class="types"> <h2>Member Type Documentation</h2> <!-- $$$State$$$Invalid$$$Intermediate$$$Acceptable --> <h3 class="fn" id="State-enum"><a name="State-enum"></a>enum QValidator::<span class="name">State</span></h3> <p>This enum type defines the states in which a validated string can exist.</p> <div class="table"><table class="valuelist"><tr valign="top" class="odd"><th class="tblConst">Constant</th><th class="tblval">Value</th><th class="tbldscr">Description</th></tr> <tr><td class="topAlign"><code>QValidator::Invalid</code></td><td class="topAlign tblval"><code>0</code></td><td class="topAlign">The string is <i>clearly</i> invalid.</td></tr> <tr><td class="topAlign"><code>QValidator::Intermediate</code></td><td class="topAlign tblval"><code>1</code></td><td class="topAlign">The string is a plausible intermediate value.</td></tr> <tr><td class="topAlign"><code>QValidator::Acceptable</code></td><td class="topAlign tblval"><code>2</code></td><td class="topAlign">The string is acceptable as a final result; i.e. it is valid.</td></tr> </table></div> <!-- @@@State --> </div> <div class="func"> <h2>Member Function Documentation</h2> <!-- $$$QValidator[overload1]$$$QValidatorQObject* --> <h3 class="fn" id="QValidator"><a name="QValidator"></a>QValidator::<span class="name">QValidator</span>(<span class="type"><a href="../qtcore/qobject.html#QObject">QObject</a></span> *<i>parent</i> = nullptr)</h3> <p>Sets up the validator. The <i>parent</i> parameter is passed on to the <a href="../qtcore/qobject.html">QObject</a> constructor.</p> <!-- @@@QValidator --> <!-- $$$~QValidator[overload1]$$$~QValidator --> <h3 class="fn" id="dtor.QValidator"><a name="dtor.QValidator"></a><code>[virtual] </code>QValidator::<span class="name">~QValidator</span>()</h3> <p>Destroys the validator, freeing any storage and other resources used.</p> <!-- @@@~QValidator --> <!-- $$$changed[overload1]$$$changed --> <h3 class="fn" id="changed"><a name="changed"></a><code>[signal] </code><span class="type">void</span> QValidator::<span class="name">changed</span>()</h3> <p>This signal is emitted when any property that may affect the validity of a string has changed.</p> <!-- @@@changed --> <!-- $$$fixup[overload1]$$$fixupQString& --> <h3 class="fn" id="fixup"><a name="fixup"></a><code>[virtual] </code><span class="type">void</span> QValidator::<span class="name">fixup</span>(<span class="type"><a href="../qtcore/qstring.html">QString</a></span> &<i>input</i>) const</h3> <p>This function attempts to change <i>input</i> to be valid according to this validator's rules. It need not result in a valid string: callers of this function must re-test afterwards; the default does nothing.</p> <p>Reimplementations of this function can change <i>input</i> even if they do not produce a valid string. For example, an ISBN validator might want to delete every character except digits and "-", even if the result is still not a valid ISBN; a surname validator might want to remove whitespace from the start and end of the string, even if the resulting string is not in the list of accepted surnames.</p> <!-- @@@fixup --> <!-- $$$locale[overload1]$$$locale --> <h3 class="fn" id="locale"><a name="locale"></a><span class="type"><a href="../qtcore/qlocale.html">QLocale</a></span> QValidator::<span class="name">locale</span>() const</h3> <p>Returns the locale for the validator. The locale is by default initialized to the same as QLocale().</p> <p><b>See also </b><a href="qvalidator.html#setLocale">setLocale</a>() and <a href="../qtcore/qlocale.html#QLocale">QLocale::QLocale</a>().</p> <!-- @@@locale --> <!-- $$$setLocale[overload1]$$$setLocaleconstQLocale& --> <h3 class="fn" id="setLocale"><a name="setLocale"></a><span class="type">void</span> QValidator::<span class="name">setLocale</span>(const <span class="type"><a href="../qtcore/qlocale.html">QLocale</a></span> &<i>locale</i>)</h3> <p>Sets the <i>locale</i> that will be used for the validator. Unless setLocale has been called, the validator will use the default locale set with <a href="../qtcore/qlocale.html#setDefault">QLocale::setDefault</a>(). If a default locale has not been set, it is the operating system's locale.</p> <p><b>See also </b><a href="qvalidator.html#locale">locale</a>() and <a href="../qtcore/qlocale.html#setDefault">QLocale::setDefault</a>().</p> <!-- @@@setLocale --> <!-- $$$validate[overload1]$$$validateQString&int& --> <h3 class="fn" id="validate"><a name="validate"></a><code>[pure virtual] </code><span class="type"><a href="qvalidator.html#State-enum">QValidator::State</a></span> QValidator::<span class="name">validate</span>(<span class="type"><a href="../qtcore/qstring.html">QString</a></span> &<i>input</i>, <span class="type">int</span> &<i>pos</i>) const</h3> <p>This virtual function returns <a href="qvalidator.html#State-enum">Invalid</a> if <i>input</i> is invalid according to this validator's rules, <a href="qvalidator.html#State-enum">Intermediate</a> if it is likely that a little more editing will make the input acceptable (e.g. the user types "4" into a widget which accepts integers between 10 and 99), and <a href="qvalidator.html#State-enum">Acceptable</a> if the input is valid.</p> <p>The function can change both <i>input</i> and <i>pos</i> (the cursor position) if required.</p> <!-- @@@validate --> </div> </div> </div> </div> </div> </div> <div class="footer"> <p> <acronym title="Copyright">©</acronym> 2018 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners.<br/> The documentation provided herein is licensed under the terms of the <a href="http://www.gnu.org/licenses/fdl.html">GNU Free Documentation License version 1.3</a> as published by the Free Software Foundation.<br/> Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners. </p> </div> </body> </html>