以下只返回nil:
[doneBarButtonItem titleTextAttributesForState:UIControlStatenormal]
注意:我通过这样做证实了这一点:
UIFont *font = [UIFont boldSystemFontOfSize:17]; [doneBarButtonItem setTitleTextAttributes:@{NSFontAttributeName: font} forState:UIControlStatenormal];
然后,我拍摄了前&之后进行比较.他们是一样的