It's in NSFormatter. You just override it in your subclass.
Cheers,
Andre Masse
------------------------------------------------------------------------
William Squires <mailto:wsqui...@satx.rr.com>
September 28, 2011 20:48
Okay, but where does the code go? Is this a delegate method in
NSTextField, or in it's parent window's view controller?
------------------------------------------------------------------------
Andre Masse <mailto:andre.ma...@videotron.ca>
September 28, 2011 17:04
You can use formatters for this too. Here's the code I'm using (modify
the characters you need to allow in addCharactersInString:).
// allow only digits and +-*/.
- (BOOL)isPartialStringValid:(NSString **)partialStringPtr
proposedSelectedRange:(NSRangePointer)proposedSelRangePtr
originalString:(NSString *)origString
originalSelectedRange:(NSRange)origSelRange
errorDescription:(NSString **)error
{
NSMutableCharacterSet *alphaNums = [NSMutableCharacterSet
decimalDigitCharacterSet];
[alphaNums addCharactersInString:@"+-*/."];
NSCharacterSet *inStringSet = [NSCharacterSet
characterSetWithCharactersInString:*partialStringPtr];
if ([alphaNums isSupersetOfSet:inStringSet]) {
return YES;
}
return NO;
}
Cheers,
Andre Masse
------------------------------------------------------------------------
Graham Cox <mailto:graham....@bigpond.com>
September 28, 2011 03:02
The preferred, supported way is to use a NSFormatter attached to the
field. This has the ability to fully constrain and convert values to
and from the field's text representation. This is designed to be
subclassed. It's unusual to subclass NSTextField itself, especially as
it's not the text field that is actually performing the text entry,
but a hidden NSTextView called the field editor. Formatters can
disallow the focus to be changed away from the text field if the
content is not valid. To prevent characters from being entered as
they're typed, you'll also want to use the field editor's delegate
methods to reject unwanted characters (formatters only validate after
the entry is submitted).
--Graham
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William Squires <mailto:wsqui...@satx.rr.com>
September 27, 2011 21:41
Hi,
I have a need for a complex data-entry form (window). Some fields are
supposed to only accept alpha characters (upper or lower), some are
supposed to only take integers, others to only take floats (but no
negative values allowed). Is there a general way of validating the
contents of a field before it resigns first responder status? Even
better, is there a way to encapsulate that behavior in an NSTextField
subclass so that I can make, say, an AlphaOnlyTextField class, drag a
(normal) NSTextField onto the window in IB, then change it's super to
"AlphaOnlyTextField", or some such? This way I can save a lot of time,
and will have a reusable control (sub)class that I can then use in
other projects!
I'm still using Xcode 3.somethingorother, and IB for my MacOS X/iOS work.
Here's the control flow I hope to tap into:
Control (an NSTextField) has focus (is first responder) - user types
something into the NSTextField
User tabs (or shift-tabs) to the next control, or clicks the mouse on
another control
NSTextField that currently has first responder status checks to see if
it has a delegate, and - if it does - does it respond to validate:? If
so, the delegate gets sent the validate: message which returns a BOOL.
If the control's contents (it's stringValue in the case of an
NSTextField) has valid input, it'll return YES to indicate that the
control may lose first responder. If it returns NO, then the attempt
to lose first responder status is nullified, and the control keeps its
first responder status.
User finally types in valid input, and the validate: returns YES. The
NSTextField now loses first responder, and some other control on the
view now gets first responder status.
Doable? Basically, I'd like to subclass NSTextField and the subclass
would implement the delegate protocol's validate: message (method);
the subclass would set itself as it's own delegate in the
awakeFromNib: method, then remove itself somewhere else (when the
control, and it's parent window, dies.) Even better, can I trap (and
kill) invalid characters as they're entered? (i.e. an NSTextField that
only allows (A-Z | a-z), and converts the characters to upper- or
lower-case, say?
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