1QValidator(3qt)                                                QValidator(3qt)
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NAME

6       QValidator - Validation of input text
7

SYNOPSIS

9       #include <qvalidator.h>
10
11       Inherits QObject.
12
13       Inherited by QIntValidator, QDoubleValidator, and QRegExpValidator.
14
15   Public Members
16       QValidator ( QObject * parent, const char * name = 0 )
17       ~QValidator ()
18       enum State { Invalid, Intermediate, Valid = Intermediate, Acceptable }
19       virtual State validate ( QString & input, int & pos ) const = 0
20       virtual void fixup ( QString & input ) const
21

DESCRIPTION

23       The QValidator class provides validation of input text.
24
25       The class itself is abstract. Two subclasses, QIntValidator and
26       QDoubleValidator, provide basic numeric-range checking, and
27       QRegExpValidator provides general checking using a custom regular
28       expression.
29
30       If the built-in validators aren't sufficient, you can subclass
31       QValidator. The class has two virtual functions: validate() and
32       fixup().
33
34       validate() must be implemented by every subclass. It returns Invalid,
35       Intermediate or Acceptable depending on whether its argument is valid
36       (for the subclass's definition of valid).
37
38       These three states require some explanation. An Invalid string is
39       clearly invalid. Intermediate is less obvious: the concept of validity
40       is slippery when the string is incomplete (still being edited).
41       QValidator defines Intermediate as the property of a string that is
42       neither clearly invalid nor acceptable as a final result. Acceptable
43       means that the string is acceptable as a final result. One might say
44       that any string that is a plausible intermediate state during entry of
45       an Acceptable string is Intermediate.
46
47       Here are some examples:
48
49       For a line edit that accepts integers from 0 to 999 inclusive, 42 and
50       123 are Acceptable, the empty string and 1114 are Intermediate and asdf
51       is Invalid.
52
53       For an editable combobox that accepts URLs, any well-formed URL is
54       Acceptable, "http://www.trolltech.com/," is Intermediate (it might be a
55       cut and paste operation that accidentally took in a comma at the end),
56       the empty string is Intermediate (the user might select and delete all
57       of the text in preparation for entering a new URL), and "http:///./" is
58       Invalid.
59
60       For a spin box that accepts lengths, "11cm" and "1in" are Acceptable,
61       "11" and the empty string are Intermediate and"
62       http://www.trolltech.com" and "hour" are Invalid.
63
64       fixup() is provided for validators that can repair some user errors.
65       The default implementation does nothing. QLineEdit, for example, will
66       call fixup() if the user presses Enter (or Return) and the content is
67       not currently valid. This allows the fixup() function the opportunity
68       of performing some magic to make an Invalid string Acceptable.
69
70       QValidator is typically used with QLineEdit, QSpinBox and QComboBox.
71
72       See also Miscellaneous Classes.
73
74   Member Type Documentation

QValidator::State

76       This enum type defines the states in which a validated string can
77       exist.
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79       QValidator::Invalid - the string is clearly invalid.
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81       QValidator::Intermediate - the string is a plausible intermediate value
82       during editing.
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84       QValidator::Acceptable - the string is acceptable as a final result,
85       i.e. it is valid.
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MEMBER FUNCTION DOCUMENTATION

QValidator::QValidator ( QObject * parent, const char * name = 0 )

89       Sets up the validator. The parent and name parameters are passed on to
90       the QObject constructor.
91

QValidator::~QValidator ()

93       Destroys the validator, freeing any storage and other resources used.
94

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

96       This function attempts to change input to be valid according to this
97       validator's rules. It need not result in a valid string: callers of
98       this function must re-test afterwards; the default does nothing.
99
100       Reimplementations of this function can change input even if they do not
101       produce a valid string. For example, an ISBN validator might want to
102       delete every character except digits and "-", even if the result is
103       still not a valid ISBN; a surname validator might want to remove
104       whitespace from the start and end of the string, even if the resulting
105       string is not in the list of accepted surnames.
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State QValidator::validate ( QString & input, int & pos ) const [pure virtual]

108
109       This pure virtual function returns Invalid if input is invalid
110       according to this validator's rules, Intermediate if it is likely that
111       a little more editing will make the input acceptable (e.g. the user
112       types '4' into a widget which accepts integers between 10 and 99) and
113       Acceptable if the input is valid.
114
115       The function can change input and pos (the cursor position) if it wants
116       to.
117
118       Reimplemented in QIntValidator, QDoubleValidator, and QRegExpValidator.
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120

SEE ALSO

122       http://doc.trolltech.com/qvalidator.html
123       http://www.trolltech.com/faq/tech.html
124
126       Copyright 1992-2007 Trolltech ASA, http://www.trolltech.com.  See the
127       license file included in the distribution for a complete license
128       statement.
129

AUTHOR

131       Generated automatically from the source code.
132

BUGS

134       If you find a bug in Qt, please report it as described in
135       http://doc.trolltech.com/bughowto.html.  Good bug reports help us to
136       help you. Thank you.
137
138       The definitive Qt documentation is provided in HTML format; it is
139       located at $QTDIR/doc/html and can be read using Qt Assistant or with a
140       web browser. This man page is provided as a convenience for those users
141       who prefer man pages, although this format is not officially supported
142       by Trolltech.
143
144       If you find errors in this manual page, please report them to qt-
145       bugs@trolltech.com.  Please include the name of the manual page
146       (qvalidator.3qt) and the Qt version (3.3.8).
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150Trolltech AS                    2 February 2007                QValidator(3qt)
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