Log NSWindow key view loop starting at the first responder.

NSWindow+KVLoop.h

@interface NSWindow (KVLoop)
- (IBAction)logKeyViewLoop:(id)sender;
@end

NSWindow+KVLoop.m

#include "NSWindow+KVLoop.h"
@implementation NSWindow (KVLoop)

- (IBAction)logKeyViewLoop:(id)sender
{
    [self recalculateKeyViewLoop];
    
    if (!self.firstResponder) {
        NSLog(@"Cannot log key view loop : no first responder found.");
        return;
    }
    if (![self.firstResponder isKindOfClass:[NSView class]]) {
        NSLog(@"Cannot log key view loop : first responder is not a view.");
        return;
    }
    
    NSView *view = (NSView *)self.firstResponder;
    NSMutableArray *visitedViews = [NSMutableArray new];
    do {
        
        // handle the field editor
        if ([view isKindOfClass:[NSTextView class]]) {
            NSTextView *textView = (NSTextView *)view;
            if (textView.isFieldEditor) {
                view = (id)textView.delegate;
            }
        }
        
        // log the next key view
        NSView *nextView = view.nextValidKeyView; // or to show all views view.nextKeyView;
        NSString *content = [view respondsToSelector:@selector(stringValue)] ? [(id)view stringValue] : @"?";
        NSString *nextContent = [nextView respondsToSelector:@selector(stringValue)] ? [(id)nextView stringValue] : @"?";
        NSString *canBecomeKeyView = [nextView acceptsFirstResponder] ? @"Y" : @"n";
        NSLog(@"%@ %@ %@ : Next key view: %@ - %@", canBecomeKeyView, view.className, content, nextView.className, nextContent);
        if (view) {
            [visitedViews addObject:view];
        }
        view = nextView;
    } while (view && ![visitedViews containsObject:view]);
    
}
@end