<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <!-- /home/espenr/tmp/qt-3.3.6-espenr-14571/qt-x11-free-3.3.6/src/widgets/qvalidator.cpp:44 --> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title>QValidator Class</title> <style type="text/css"><!-- fn { margin-left: 1cm; text-indent: -1cm; } a:link { color: #004faf; text-decoration: none } a:visited { color: #672967; text-decoration: none } body { background: #ffffff; color: black; } --></style> </head> <body> <table border="0" cellpadding="0" cellspacing="0" width="100%"> <tr bgcolor="#E5E5E5"> <td valign=center> <a href="index.html"> <font color="#004faf">Home</font></a> | <a href="classes.html"> <font color="#004faf">All Classes</font></a> | <a href="mainclasses.html"> <font color="#004faf">Main Classes</font></a> | <a href="annotated.html"> <font color="#004faf">Annotated</font></a> | <a href="groups.html"> <font color="#004faf">Grouped Classes</font></a> | <a href="functions.html"> <font color="#004faf">Functions</font></a> </td> <td align="right" valign="center"><img src="logo32.png" align="right" width="64" height="32" border="0"></td></tr></table><h1 align=center>QValidator Class Reference</h1> <p>The QValidator class provides validation of input text. <a href="#details">More...</a> <p><tt>#include <<a href="qvalidator-h.html">qvalidator.h</a>></tt> <p>Inherits <a href="qobject.html">QObject</a>. <p>Inherited by <a href="qintvalidator.html">QIntValidator</a>, <a href="qdoublevalidator.html">QDoubleValidator</a>, and <a href="qregexpvalidator.html">QRegExpValidator</a>. <p><a href="qvalidator-members.html">List of all member functions.</a> <h2>Public Members</h2> <ul> <li class=fn><a href="#QValidator"><b>QValidator</b></a> ( QObject * parent, const char * name = 0 )</li> <li class=fn><a href="#~QValidator"><b>~QValidator</b></a> ()</li> <li class=fn>enum <a href="#State-enum"><b>State</b></a> { Invalid, Intermediate, Valid = Intermediate, Acceptable }</li> <li class=fn>virtual State <a href="#validate"><b>validate</b></a> ( QString & input, int & pos ) const = 0</li> <li class=fn>virtual void <a href="#fixup"><b>fixup</b></a> ( QString & input ) const</li> </ul> <hr><a name="details"></a><h2>Detailed Description</h2> The QValidator 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 <a href="qregexp.html#regular-expression">regular expression</a>. <p> If the built-in validators aren't sufficient, you can subclass QValidator. The class has two virtual functions: <a href="#validate">validate</a>() and <a href="#fixup">fixup</a>(). <p> <a href="#validate">validate</a>() must be implemented by every subclass. It returns <a href="#State-enum">Invalid</a>, <a href="#State-enum">Intermediate</a> or <a href="#State-enum">Acceptable</a> depending on whether its argument is valid (for the subclass's definition of valid). <p> These three states require some explanation. An <a href="#State-enum">Invalid</a> string is <em>clearly</em> invalid. <a href="#State-enum">Intermediate</a> is less obvious: the concept of validity is slippery when the string is incomplete (still being edited). QValidator defines <a href="#State-enum">Intermediate</a> as the property of a string that is neither clearly invalid nor acceptable as a final result. <a href="#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="#State-enum">Acceptable</a> string is <a href="#State-enum">Intermediate</a>. <p> Here are some examples: <p> <ul> <p> <li> For a line edit that accepts integers from 0 to 999 inclusive, 42 and 123 are <a href="#State-enum">Acceptable</a>, the empty string and 1114 are <a href="#State-enum">Intermediate</a> and asdf is <a href="#State-enum">Invalid</a>. <p> <li> For an editable combobox that accepts URLs, any well-formed URL is <a href="#State-enum">Acceptable</a>, "http://www.trolltech.com/," is <a href="#State-enum">Intermediate</a> (it might be a cut and paste operation that accidentally took in a comma at the end), the empty string is <a href="#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="#State-enum">Invalid</a>. <p> <li> For a spin box that accepts lengths, "11cm" and "1in" are <a href="#State-enum">Acceptable</a>, "11" and the empty string are <a href="#State-enum">Intermediate</a> and "http://www.trolltech.com" and "hour" are <a href="#State-enum">Invalid</a>. <p> </ul> <p> <a href="#fixup">fixup</a>() is provided for validators that can repair some user errors. The default implementation does nothing. <a href="qlineedit.html">QLineEdit</a>, for example, will call <a href="#fixup">fixup</a>() if the user presses Enter (or Return) and the content is not currently valid. This allows the fixup() function the opportunity of performing some magic to make an <a href="#State-enum">Invalid</a> string <a href="#State-enum">Acceptable</a>. <p> QValidator is typically used with QLineEdit, <a href="qspinbox.html">QSpinBox</a> and <a href="qcombobox.html">QComboBox</a>. <p>See also <a href="misc.html">Miscellaneous Classes</a>. <hr><h2>Member Type Documentation</h2> <h3 class=fn><a name="State-enum"></a>QValidator::State</h3> <p> This enum type defines the states in which a validated string can exist. <ul> <li><tt>QValidator::Invalid</tt> - the string is <em>clearly</em> invalid. <li><tt>QValidator::Intermediate</tt> - the string is a plausible intermediate value during editing. <li><tt>QValidator::Acceptable</tt> - the string is acceptable as a final result, i.e. it is valid. </ul> <hr><h2>Member Function Documentation</h2> <h3 class=fn><a name="QValidator"></a>QValidator::QValidator ( <a href="qobject.html">QObject</a> * parent, const char * name = 0 ) </h3> Sets up the validator. The <em>parent</em> and <em>name</em> parameters are passed on to the <a href="qobject.html">QObject</a> constructor. <h3 class=fn><a name="~QValidator"></a>QValidator::~QValidator () </h3> Destroys the validator, freeing any storage and other resources used. <h3 class=fn>void <a name="fixup"></a>QValidator::fixup ( <a href="qstring.html">QString</a> & input ) const<tt> [virtual]</tt> </h3> <p> This function attempts to change <em>input</em> 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> Reimplementations of this function can change <em>input</em> 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. <h3 class=fn><a href="qvalidator.html#State-enum">State</a> <a name="validate"></a>QValidator::validate ( <a href="qstring.html">QString</a> & input, int & pos ) const<tt> [pure virtual]</tt> </h3> <p> This pure virtual function returns <a href="#State-enum">Invalid</a> if <em>input</em> is invalid according to this validator's rules, <a href="#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="#State-enum">Acceptable</a> if the input is valid. <p> The function can change <em>input</em> and <em>pos</em> (the cursor position) if it wants to. <p>Reimplemented in <a href="qintvalidator.html#validate">QIntValidator</a>, <a href="qdoublevalidator.html#validate">QDoubleValidator</a>, and <a href="qregexpvalidator.html#validate">QRegExpValidator</a>. <!-- eof --> <hr><p> This file is part of the <a href="index.html">Qt toolkit</a>. 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