NSTextField edit coalescing

1
votes

I am writing a Cocoa app which contains several NSTextFields. I am trying to propagate changes to the text in the text field to my model layer, but since I am registering an Undo action when the model is updated, this makes it a bit more complicated than simply listening for controlTextDidChange:.

If I hook onto the delegate method controlTextDidChange:, then it gets called once for every key pressed. If I update the model then, the model will treat each separate keypress as a separate Undo event. This is not desirable. What I want is to be notified when the default "Undo Typing" action is registered with the Undo manager, so I can update the model then. The NSTextField registers one (and only one) such event, when I pause typing for a moment. Unfortunately, I have no idea when this occurs.

I have tried listening for controlTextDidEndEditing:, and updating the model in that delegate method, but then I have to explicitly tab out of the text field before the model will update. Since I archive my model object directly in my NSDocument subclass, doing this will result in data loss for the user if they save the document after changing the contents of the text field, but don't tab out of the text field first, because the model would not have been updated in time. Therefore, this technique will not work.

I have also tried hooking onto the text field's field editor (during control:textShouldBeginEditing:) and listening for textDidEndEditing:, but then I find that this simply doesn't fire, so the model won't be updated, causing data loss as described in the previous paragraph. Can anyone help me figure this out? Thanks!

1
cocoanstextfield
Take a look at the NSEditor protocol. - Willeke
I've looked at NSEditor, but since I'm not using bindings (because they are not compatible with my model architecture), I'm not certain how to wire up my view controller (which is responsible for updating the model) so it receives the messages. - wjk
Were you ever able to solve this? I'm running into a similar issue. This must be possible, because NSTextField does it. More details and sample code here: stackoverflow.com/questions/58409945/… - Mark

1 Answers

0
votes

By default, Apple NSTextField leaves dangling edits as you mentioned. Because of this problem, amongst others, I subclassed NSTextField and NSApplication to handle text field editing the way it should be handled: Pressing 'Enter', clicking outside the field, and other actions should end editing and produce the Undo entry.

Also, I highly recommend GCUndoManager replacement for NSUndoManager.