On Jul 11, 2013, at 9:00 AM, Matthew LeRoy wrote: > I'm trying to implement some input validation on an NSTextField using > NSControlTextEditingDelegate's -control:isValidObject: method -- simple stuff > like validating that the entered text is parsable as a number, falls within a > certain range, etc. (I know that NSNumberFormatter is the obvious choice for > this scenario, but I'm working with requirements that require more low-level > customizability, particularly in the content of the error message and how it > is presented to the user, than NSNumberFormatter allows.) I've got things > generally working; the delegate method gets called, I validate the user's > entry and return NO if it is invalid, and the text field remains first > responder. > > The obstacle I've encountered is that in some cases my text field is a > subordinate control that is enabled/disabled based on a checkbox elsewhere in > my view. If the user enters something invalid and attempts to commit the edit > by pressing tab/enter/return, I validate and display the error message and > the text field remains first responder, as desired. However, if the user then > unchecks the controlling checkbox -- causing the text field to be disabled > via -setEnabled:NO in my view controller -- the text field is disabled but it > keeps the invalid text. > > At this point, the user has successfully circumvented my input validation; > they can just re-check the checkbox and the text field is reenabled > containing the invalid text. Worse, if the user puts key focus in the > NSTextField again but does not make any edits and then tabs out, the > validation is not triggered because there are no pending edits. I do note > that if the user enters invalid text but does not attempt to commit the edit > and then unchecks the checkbox, the NSTextField is disabled and the text > reverts back to what it was before the user made their edit. It seems that > even though I'm returning NO from -control:isValidObject:, the edit is still > 'committed' from the field editor to the NSTextField. What I want is for the > text field to revert back to the previous valid entry upon unchecking the > box, even after the user attempts to commit the invalid edit and is presented > with an error message. > > So, it sounds like -control:isValidObject: might be too late in the pipeline > to validate and prevent the edit from being committed in the first place. Any > suggestions for an earlier point to hook in my validation? I did try > -control:textShouldEndEditing:, but still see the same behavior. Or, a > different approach to accomplish what I'm after?
It may be more likely the case that because a checkbox is a button, buttons do not cause a change in the first responder so there is no explicit "commit" of the editing value. It is curious, however, that when the field is disabled it retains the invalid value. I would file a radar on that... Anyway, I would add to the action method for the checkbox to make the view controller commit any pending edits and if it fails to reject the change in the button state and hence disabling the NSTextField. HTH, Keary Suska Esoteritech, Inc. "Demystifying technology for your home or business" _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
