The QValidator class provides validation of input text. More...
Inherited by QDoubleValidator and QIntValidator.
List of all member functions.
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
depending on whether its argument is valid (for the class'
definition of valid).
The three states require some explanation. An
Invalid string is
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
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
Here are some examples:
Acceptable,the empty string and 1114 are
Intermediateand asdf is
Intermediate(it can be a cut-and-paste job that accidentally took in a comma at the end), the empty string is valid (the user might select and delete all of the text in preparation to entering a new URL), and "http:///./" is
Acceptable,"11" and the empty string are
Intermediate,and "http://www.trolltech.com" and "hour" are
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.
Invalid- the string is clearly invalid.
Intermediate- the string is a plausible intermediate value during editing.
Acceptable- acceptable as a final result.
Valid has been renamed
Intermediate. The old name
confused too many people and is now obsolete.
Sets up the internal data structures used by the validator. At the moment there aren't any.
Destroys the validator, freeing any storage and other resources used.
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.
Reimplementations of this function can change input 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 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.
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
the input is completely acceptable.
The function can change input and pos (the cursor position) if it wants to.
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