Re: Substituting instance of cell subclass for instance of superclass
Re: Substituting instance of cell subclass for instance of superclass
- Subject: Re: Substituting instance of cell subclass for instance of superclass
- From: Kyle Sluder <email@hidden>
- Date: Fri, 11 Nov 2016 20:27:46 -0600
On Fri, Nov 11, 2016, at 07:34 PM, James Walker wrote:
> I want to replace (for example) an instance of NSButtonCell with an
> instance of my own subclass of NSButtonCell on the fly. Now, I know
> that's not a common thing to want to do; normally, you'd edit the nib to
> use whatever cell class you want. But I'd like to be able to do it to
> an NSAlert, for which I don't have a nib.
You also have no idea if the NSAlert is already using a custom
NSButtonCell subclass—or whether it uses NSControl at all.
Your only option here is to reimplement the alert.
--Kyle Sluder
>
> So, my thought was to first make an instance of my cell class that
> copies all the state of the NSButtonCell instance, and then use
> -[NSControl setCell:]. The documentation on setCell: does say:
> "Use this method with great care as it can irrevocably damage the
> affected control; specifically, you should only use this method in
> initializers for subclasses of NSControl."
> Anyone know what kind of damage we're talking about?
>
> Anyway, as far as copying the cell state, I tried this:
>
> - (id) initCopyingBaseCell: (NSButtonCell*) oldCell
> {
> NSData* archive = [NSKeyedArchiver
> archivedDataWithRootObject: oldCell];
> NSKeyedUnarchiver* coder = [[[NSKeyedUnarchiver alloc]
> initForReadingWithData: archive] autorelease];
>
> self = [super initWithCoder: coder];
> if (self != nil)
> {
>
> }
> return self;
> }
>
> However, the new cell has failed to copy much of the state of the old
> one. Things like title, font, target, action, bezelStyle... I can
> manually copy anything that I notice is missing, but I'm just wondering
> why the keyed archiver approach here doesn't work.
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