The NSPopOver, a new addition to the Cocoa toolkit since OS X 10.7, is an excellent way to give the user feedback on actions requiring their input. In my use case, I needed to be able to show an NSPopOver containing a multiline label populated with a string of varying length.
Getting the NSPopOver, NSView & NTextField all working perfectly was very basic.
Ensuring that the NSPopOver’s NSView & NSTextField resized appropriately was more challenging.
I needed to get the rectangle that my string would fill when drawn. A short Google search led me here: SO: NSString sizeWithAttributes: Content Rect. As I know I’ll be doing this again, I made a category of NSString that provides this.
The rest was simple:
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NSSize size = [string sizeWithWidth:200.0 andFont:[textLabel font]]; [view setFrameSize:NSMakeSize(size.width + 30, size.height + 30)]; [textLabel setFrame:NSMakeRect(15, 15, size.width, size.height)]; [textLabel setStringValue:string]; popover.contentSize = view.frame.size; [popover showRelativeToRect:[textField bounds] ofView:textField preferredEdge:NSMaxXEdge];
The NSString+Size category is available here: Cocoa Categories.
After doing this, I rethought my approach and streamlined it by creating a category on NSPopover, which is available in the above repository. I wrote about the process here: User Feedback & the NSPopover.