QValidator - Validation of input text

       #include <qvalidator.h>

       Inherits QObject.

       Inherited by QDoubleValidator and QIntValidator.

   Public Members
       QValidator ( QWidget * parent, const char * name = 0 )
       ~QValidator ()
       enum State { Invalid, Intermediate, Valid=Intermediate,
           Acceptable }
       virtual State validate ( QString &, int & ) const
       virtual void fixup ( QString & ) const


DESCRIPTION

       The QValidator class provides validation of input text.

       The class itself is abstract; two subclasses provide
       rudimentary numeric range checking.

       The class includes two virtual functions, validate() and
       fixup().

       validate() is pure virtual, so it must be implemented by
       every subclass. It returns Invalid, Intermediate or
       Acceptable depending on whether its argument is valid (for
       the class' definition of valid).

       The three states require some explanation. An Invalid
       string is clearly invalid. Intermediate is less obvious -
       the concept of validity is slippery when the string is
       incomplete (still being edited). QValidator defines
       Intermediate as the property of a string that it is
       neither clearly invalid or acceptable as a final result.
       Acceptable 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 Acceptable string is
       Intermediate.

       Here are some examples:

       1      For a line edit that accepts integers from 0 to 999
              inclusive, 42 and 666 are Acceptable, the empty
              string and 1114 are Intermediate and asdf is
              Invalid.

       2      For an editable combo box that accepts URLs, any
              well-formed URL is Acceptable,
              "http://www.trolltech.com/," is Intermediate (it
              can be a cut-and-paste job that accidentally took

              (the user might select and delete all of the text
              in preparation to entering a new URL), and"
              http:///./" is Invalid.

       3      For a spin box that accepts lengths, "11cm" and
              "1in" are Acceptable, "11" and the empty string are
              Intermediate, and" http://www.trolltech.com" and
              "hour" are Invalid.

       fixup() is provided for validators that can repair some or
       all user errors. The default does nothing. QLineEdit, for
       example, will call fixup() if the user presses Return and
       the content is not currently valid, in case fixup() can do
       magic. This allows some Invalid strings to be made
       Acceptable, too, spoiling the muddy definition above even
       more.

       QValidator is generally used with QLineEdit, QSpinBox and
       QComboBox.

   Member Type Documentation

QValidator::State

       This enum type defines the states in which a validated
       string can be. There are currently three states:

       Invalid - the string is clearly invalid.

       Intermediate - the string is a plausible intermediate
              value during editing.

       Acceptable - acceptable as a final result.

       The state Valid has been renamed Intermediate. The old
       name confused too many people and is now obsolete.


MEMBER FUNCTION DOCUMENTATION


QValidator::QValidator ( QWidget * parent, const char * name = 0

       )
       Sets up the internal data structures used by the
       validator. At the moment there aren't any.


QValidator::~QValidator ()

       Destroys the validator, freeing any storage and other
       resources used.


void QValidator::fixup ( QString & input ) const [virtual]

       Attempts to change input to be valid according to this
       validator's rules. Need not result in a valid string -
       callers of this function must re-test afterwards. The
       default does nothing.

       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 not a valid ISBN,
       and a last-name validator might want to remove white space
       from the start and end of the string, even if the
       resulting string is not in the list of known last names.


QValidator::State QValidator::validate( QString & input, int &

       pos ) const
       This pure virtual function returns Invalid if input is
       invalid according to this validator's rules, Intermediate
       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 10-99) and Acceptable if the input is
       completely acceptable.

       The function can change input and pos (the cursor
       position) if it wants to.


SEE ALSO

       http://doc.trolltech.com/qvalidator.html
       http://www.trolltech.com/faq/tech.html


COPYRIGHT

       Copyright 1992-2001 Trolltech AS,
       http://www.trolltech.com.  See the license file included
       in the distribution for a complete license statement.


AUTHOR

       Generated automatically from the source code.


BUGS

       If you find a bug in Qt, please report it as described in
       http://doc.trolltech.com/bughowto.html.  Good bug reports
       make our job much simpler. Thank you.

       In case of content or formattting problems with this
       manual page, please report them to qt-bugs@trolltech.com.
       Please include the name of the manual page
       (qvalidator.3qt) and the Qt version (2.3.1).


Man(1) output converted with man2html