titleTextAttributes UIAppearance font in iOS 7

Question

I am using UIAppearance to apply fonts to UINavigationBar and UIBarButtonItem and I am having problems. I ran this code:

[[UIBarButtonItem appearanceWhenContainedIn:[UIToolbar class], nil] 
setTitleTextAttributes:
@{NSFontAttributeName : [UIFont fontWithName:@"My_Font" size:17.0]} 
forState:UIControlStateNormal];

NSLog(@"%@", [[UIBarButtonItem appearanceWhenContainedIn:
[UIToolbar class], nil] titleTextAttributesForState:UIControlStateNormal]);

and the result of that log on iOS 7 is:

(null)

Where the result in iOS 6 is:

{
    NSFont = "<UICFFont: 0x1d897a80> font-family: \"My_Font\"; font-weight: normal; font-style: normal; font-size: 17px";
}

I can't find anything in the iOS 7 docs that would indicate that this shouldn't work, has anyone else had this problem?

Edit 1

I actually have gotten this to work with [UINavigationBar appearance] the problem was that I was setting the point size to 0 in order to have the font be set to the default navbar/barButtonItem size as described in the NSString UIKit Additions Reference but this apparently no longer works in iOS 7. Instead, setting the point size to 0 will return the system font.

I am still unable to set titleTextAttributes to

[UIBarButtonItem appearanceWhenContaintedIn:[UIToolbar class], nil]]

Answer 1

NSDictionary *attributes = [NSDictionary dictionaryWithObjectsAndKeys:[UIFont 
    fontWithName:@"YOURFONT" size:14], NSFontAttributeName, 
    [UIColor whiteColor], NSForegroundColorAttributeName, nil];

[[UINavigationBar appearance] setTitleTextAttributes:attributes];

The key is to use NSFontAttributeName and so forth. I assume they are moving over to using the NS variety for 64-bit compatibility. The above code worked on my iOS7 device.