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<td align="right" valign="center"><img src="logo32.png" align="right" width="64" height="32" border="0"></td></tr></table><h1 align=center>TQValidator Class Reference</h1>
<p>The TQValidator class provides validation of input text.
<a href="#details">More...</a>
<p><tt>#include <<a href="qvalidator-h.html">ntqvalidator.h</a>></tt>
<p>Inherits <a href="tqobject.html">TQObject</a>.
<p>Inherited by <a href="qintvalidator.html">TQIntValidator</a>, <a href="qdoublevalidator.html">TQDoubleValidator</a>, and <a href="qregexpvalidator.html">TQRegExpValidator</a>.
<p><a href="qvalidator-members.html">List of all member functions.</a>
<h2>Public Members</h2>
<ul>
<li class=fn><a href="#TQValidator"><b>TQValidator</b></a> ( TQObject * parent, const char * name = 0 )</li>
<li class=fn><a href="#~TQValidator"><b>~TQValidator</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> ( TQString & input, int & pos ) const = 0</li>
<li class=fn>virtual void <a href="#fixup"><b>fixup</b></a> ( TQString & input ) const</li>
</ul>
<hr><a name="details"></a><h2>Detailed Description</h2>
The TQValidator class provides validation of input text.
<p>
<p> The class itself is abstract. Two subclasses, <a href="qintvalidator.html">TQIntValidator</a> and
<a href="qdoublevalidator.html">TQDoubleValidator</a>, provide basic numeric-range checking, and <a href="qregexpvalidator.html">TQRegExpValidator</a> provides general checking using a custom <a href="ntqregexp.html#regular-expression">regular expression</a>.
<p> If the built-in validators aren't sufficient, you can subclass
TQValidator. 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). TQValidator 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="ntqlineedit.html">TQLineEdit</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> TQValidator is typically used with TQLineEdit, <a href="ntqspinbox.html">TQSpinBox</a> and
<a href="ntqcombobox.html">TQComboBox</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>TQValidator::State</h3>
<p> This enum type defines the states in which a validated string can
exist.
<ul>
<li><tt>TQValidator::Invalid</tt> - the string is <em>clearly</em> invalid.
<li><tt>TQValidator::Intermediate</tt> - the string is a plausible intermediate value
during editing.
<li><tt>TQValidator::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="TQValidator"></a>TQValidator::TQValidator ( <a href="tqobject.html">TQObject</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="tqobject.html">TQObject</a> constructor.
<h3 class=fn><a name="~TQValidator"></a>TQValidator::~TQValidator ()
</h3>
Destroys the validator, freeing any storage and other resources
used.
<h3 class=fn>void <a name="fixup"></a>TQValidator::fixup ( <a href="tqstring.html">TQString</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="ntqvalidator.html#State-enum">State</a> <a name="validate"></a>TQValidator::validate ( <a href="tqstring.html">TQString</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">TQIntValidator</a>, <a href="qdoublevalidator.html#validate">TQDoubleValidator</a>, and <a href="qregexpvalidator.html#validate">TQRegExpValidator</a>.
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