Question

Has anyone ever had experience embedding a field editor (for a NSTextField) inside a scroll view? I’m trying to make the NSTextField scrollable while editing.

Things I’ve tried:

1. Dynamically embed it when the custom field editor’s -becomeFirstResponder gets called. This semi works; the problem is that when the NSTextField gets resized during editing the custom field editor no longer gets resized with it (and I need this – making an accordion
   style application)

2. Create a “masquerading” field editor out of a NSScrollView, and using NSInvocation forward the methods to the actual surrogate field editor. This is the method I really hope would work; I’ve implemented all the methods as listed here; but I get an EXC_BAD_ACCESS whenever the field editor is actually loaded (e.g. when I call [customTextField selectText:nil]). I can’t seem to pry any information out of the debugger even with Zombies enabled, and looking at the logs of NSObjCMessageLoggingEnabled yields nothing either. It seems like these guys got it working but that was seven years ago.

The last resort would be to drop NSTextFields completely and use NSTextViews (or instead of relying on the field editor mechanism, write one myself), but since I have many rows of data of which only one will be edited at a time, I don’t want to instantiate a NSTextView for every single one of them… but then, perhaps it won’t be so bad.

Answer 1

I ended up using option 1, and getting it to work without much difficulty. Option 2 was a complete dead end because EXC_BAD_ACCESS popped up everywhere I went.

My custom field editor now keeps a reference to a (custom) scroll view to embed itself in (vvScrollView), and inserts it into the view hierarchy. My code inside my custom field editor (NSTextView) for embedding it inside a scroll view, which is called as soon as the field editor becomes first responder and is automatically inserted into the view hierarchy:

- (void)embedSelfInScrollView {
    NSView *realSuperview = [[self superview] superview];
    // [self superview] is some kind of private NSClipView class
    if ([realSuperview isKindOfClass:[NSTextField class]]) { // the expected behavior: this may change? TODO make less prone to chance
        [realSuperview addSubview:[self vvScrollView]]; // insert into view
        [[self vvScrollView] setFrameSize:[realSuperview frame].size]; // se the initial size equivalent to control size so it can autoresize the same way
        // add the scrollview into the view hierarchy
        [[self vvScrollView] setDocumentView:self]; // removes self from previous superview
    }
}

The initial problem I had was that I was trying to insert the scrollview into the superview immediately above the field editor’s (the private class of NSClipView) which broke almost every automatic sizing option (because I want to be able to resize the NSTextField while editing). Going a step further and bypassing the private class seems to work, but almost seems arbitrary.