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32<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>
33
34<p>The QValidator class provides validation of input text.
35<a href="#details">More...</a>
36<p><tt>#include &lt;<a href="qvalidator-h.html">qvalidator.h</a>&gt;</tt>
37<p>Inherits <a href="qobject.html">QObject</a>.
38<p>Inherited by <a href="qintvalidator.html">QIntValidator</a>, <a href="qdoublevalidator.html">QDoubleValidator</a>, and <a href="qregexpvalidator.html">QRegExpValidator</a>.
39<p><a href="qvalidator-members.html">List of all member functions.</a>
40<h2>Public Members</h2>
41<ul>
42<li class=fn><a href="#QValidator"><b>QValidator</b></a> ( QObject&nbsp;*&nbsp;parent, const&nbsp;char&nbsp;*&nbsp;name = 0 )</li>
43<li class=fn><a href="#~QValidator"><b>~QValidator</b></a> ()</li>
44<li class=fn>enum <a href="#State-enum"><b>State</b></a> { Invalid, Intermediate, Valid = Intermediate, Acceptable }</li>
45<li class=fn>virtual State <a href="#validate"><b>validate</b></a> ( QString&nbsp;&amp;&nbsp;input, int&nbsp;&amp;&nbsp;pos ) const = 0</li>
46<li class=fn>virtual void <a href="#fixup"><b>fixup</b></a> ( QString&nbsp;&amp;&nbsp;input ) const</li>
47</ul>
48<hr><a name="details"></a><h2>Detailed Description</h2>
49
50
51The QValidator class provides validation of input text.
52<p>
53
54<p> The class itself is abstract. Two subclasses, <a href="qintvalidator.html">QIntValidator</a> and
55<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>.
56<p> If the built-in validators aren't sufficient, you can subclass
57QValidator. The class has two virtual functions: <a href="#validate">validate</a>() and
58<a href="#fixup">fixup</a>().
59<p> <a href="#validate">validate</a>() must be implemented by every subclass. It returns
60<a href="#State-enum">Invalid</a>, <a href="#State-enum">Intermediate</a> or <a href="#State-enum">Acceptable</a> depending on whether
61its argument is valid (for the subclass's definition of valid).
62<p> These three states require some explanation. An <a href="#State-enum">Invalid</a> string
63is <em>clearly</em> invalid. <a href="#State-enum">Intermediate</a> is less obvious: the
64concept of validity is slippery when the string is incomplete
65(still being edited). QValidator defines <a href="#State-enum">Intermediate</a> as the
66property of a string that is neither clearly invalid nor
67acceptable as a final result. <a href="#State-enum">Acceptable</a> means that the string
68is acceptable as a final result. One might say that any string
69that is a plausible intermediate state during entry of an <a href="#State-enum">Acceptable</a> string is <a href="#State-enum">Intermediate</a>.
70<p> Here are some examples:
71<p> <ul>
72<p> <li> For a line edit that accepts integers from 0 to 999 inclusive,
7342 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>.
74<p> <li> For an editable combobox that accepts URLs, any well-formed URL
75is <a href="#State-enum">Acceptable</a>, "http://www.trolltech.com/," is <a href="#State-enum">Intermediate</a>
76(it might be a cut and paste operation that accidentally took in a
77comma at the end), the empty string is <a href="#State-enum">Intermediate</a> (the user
78might select and delete all of the text in preparation for entering
79a new URL), and "http:///./" is <a href="#State-enum">Invalid</a>.
80<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
81"http://www.trolltech.com" and "hour" are <a href="#State-enum">Invalid</a>.
82<p> </ul>
83<p> <a href="#fixup">fixup</a>() is provided for validators that can repair some user
84errors. The default implementation does nothing. <a href="qlineedit.html">QLineEdit</a>, for
85example, will call <a href="#fixup">fixup</a>() if the user presses Enter (or Return)
86and the content is not currently valid. This allows the fixup()
87function the opportunity of performing some magic to make an <a href="#State-enum">Invalid</a> string <a href="#State-enum">Acceptable</a>.
88<p> QValidator is typically used with QLineEdit, <a href="qspinbox.html">QSpinBox</a> and
89<a href="qcombobox.html">QComboBox</a>.
90<p>See also <a href="misc.html">Miscellaneous Classes</a>.
91
92<hr><h2>Member Type Documentation</h2>
93<h3 class=fn><a name="State-enum"></a>QValidator::State</h3>
94
95<p> This enum type defines the states in which a validated string can
96exist.
97<ul>
98<li><tt>QValidator::Invalid</tt> - the string is <em>clearly</em> invalid.
99<li><tt>QValidator::Intermediate</tt> - the string is a plausible intermediate value
100during editing.
101<li><tt>QValidator::Acceptable</tt> - the string is acceptable as a final result,
102i.e. it is valid.
103</ul>
104<hr><h2>Member Function Documentation</h2>
105<h3 class=fn><a name="QValidator"></a>QValidator::QValidator ( <a href="qobject.html">QObject</a>&nbsp;*&nbsp;parent, const&nbsp;char&nbsp;*&nbsp;name = 0 )
106</h3>
107Sets up the validator. The <em>parent</em> and <em>name</em> parameters are
108passed on to the <a href="qobject.html">QObject</a> constructor.
109
110<h3 class=fn><a name="~QValidator"></a>QValidator::~QValidator ()
111</h3>
112Destroys the validator, freeing any storage and other resources
113used.
114
115<h3 class=fn>void <a name="fixup"></a>QValidator::fixup ( <a href="qstring.html">QString</a>&nbsp;&amp;&nbsp;input ) const<tt> [virtual]</tt>
116</h3>
117
118<p> This function attempts to change <em>input</em> to be valid according to
119this validator's rules. It need not result in a valid string:
120callers of this function must re-test afterwards; the default does
121nothing.
122<p> Reimplementations of this function can change <em>input</em> even if
123they do not produce a valid string. For example, an ISBN validator
124might want to delete every character except digits and "-", even
125if the result is still not a valid ISBN; a surname validator might
126want to remove whitespace from the start and end of the string,
127even if the resulting string is not in the list of accepted
128surnames.
129
130<h3 class=fn><a href="qvalidator.html#State-enum">State</a> <a name="validate"></a>QValidator::validate ( <a href="qstring.html">QString</a>&nbsp;&amp;&nbsp;input, int&nbsp;&amp;&nbsp;pos ) const<tt> [pure virtual]</tt>
131</h3>
132
133<p> This pure virtual function returns <a href="#State-enum">Invalid</a> if <em>input</em> is
134invalid according to this validator's rules, <a href="#State-enum">Intermediate</a> if it
135is likely that a little more editing will make the input
136acceptable (e.g. the user types '4' into a widget which accepts
137integers between 10 and 99) and <a href="#State-enum">Acceptable</a> if the input is
138valid.
139<p> The function can change <em>input</em> and <em>pos</em> (the cursor position)
140if it wants to.
141
142<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>.
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147<a href="http://www.trolltech.com/">Trolltech</a>. All Rights Reserved.<p><address><hr><div align=center>
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151<td align=right><div align=right>Qt 3.3.8</div>
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