IIRC, you get this behavior automatically when validating with a formatter, so
applying a custom NSNumberFormatter subclass might be more canonical and less
kludgey.
HTH,
Keary Suska
Esoteritech, Inc.
"Demystifying technology for your home or business"
> On May 6, 2019, at 5:33 AM, Richard Charles <rcharles...@gmail.com> wrote:
>
> Thank you Quincey, Sean, Gary and Alex for your comments and suggestions.
>
> To recap I have a NSTextField subclass bound to an array controller using a
> derived value binding. The user selects one or more objects in a graphic
> view. Object properties are shown in an inspector containing the text field.
>
> A custom derived value binding is needed because object properties are
> floating point values with limited precision. Values that are close to equal
> are considered equal from the user's point of view.
>
> When garbage is entered into a text field and the user presses the return key
> an alert panel is presented as a sheet attached to the window. The user can
> choose "Discard Change" or "OK”.
>
> Because a custom binding is used code must be added to present the error and
> recover from the error. My text field subclass implements the
> NSErrorRecoveryAttempting informal protocol.
>
> My original discard change code did not work.
>
> - (void)attemptRecoveryFromError:(NSError *)error
> optionIndex:(NSUInteger)recoveryOptionIndex
> delegate:(id)delegate
> didRecoverSelector:(SEL)didRecoverSelector
> contextInfo:(void *)contextInfo
> {
> // Discard Change
> if (recoveryOptionIndex == 1) {
> [self abortEditing]; // does not work
> }
> }
>
> Here is a solution that works well.
>
> - (void)attemptRecoveryFromError:(NSError *)error
> optionIndex:(NSUInteger)recoveryOptionIndex
> delegate:(id)delegate
> didRecoverSelector:(SEL)didRecoverSelector
> contextInfo:(void *)contextInfo
> {
> // Discard Change
> if (recoveryOptionIndex == 1) {
> // Revert display back to original value.
> [self abortEditing];
> [self setObjectValue:self.cachedObjectValue];
> [self.window makeFirstResponder:self];
> }
> }
>
> The abortEditing message is needed otherwise the binding will push the
> updated cached object value to the model.
>
> --Richard Charles
>
> _______________________________________________
>
> 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/cocoa-dev%40esoteritech.com
>
> This email sent to cocoa-...@esoteritech.com
_______________________________________________
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
