为什么无法设置 UIBarButtonItem Disabled状态的颜色

[right setTitleTextAttributes:@{NSForegroundColorAttributeName:[UIColor redColor]} forState:UIControlStateDisabled];
这样设置了 Disabled 时候的颜色
但是
self.navigationItem.rightBarButtonItem.enabled=NO 后
依然是灰色的

---

应该使用

javascript[[UIBarButtonItem appearance] setTitleTextAttributes:@{NSForegroundColorAttributeName:[UIColor redColor]} forState:UIControlStateDisabled];

参照UIBarItem.h里面的

javascript/* You may specify the font, text color, and shadow properties for the title in the text attributes dictionary, using the keys found in NSAttributedString.h.
 */
- (void)setTitleTextAttributes:(NSDictionary *)attributes forState:(UIControlState)state NS_AVAILABLE_IOS(5_0) UI_APPEARANCE_SELECTOR;
- (NSDictionary *)titleTextAttributesForState:(UIControlState)state NS_AVAILABLE_IOS(5_0) UI_APPEARANCE_SELECTOR;

这两个方法是Appearance protocol的方法。

---

应该是调用方法的时间点上有问题，这个是我的demo代码片段

javascript- (instancetype)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];

    if (self) {
        [self setNaviagtionItem];
    }

    return self;
}

- (instancetype)init
{
    self = [super init];

    if (self) {
        [self setNaviagtionItem];
    }

    return self;
}

- (id)initWithCoder:(NSCoder *)aDecoder
{
    self = [super initWithCoder:aDecoder];

    if (self) {
        [self setNaviagtionItem];
    }

    return self;
}

- (void)setNaviagtionItem
{
    UIBarButtonItem *leftItem = [[UIBarButtonItem alloc] initWithTitle:@"bb" style:UIBarButtonItemStyleDone target:self action:nil];
    self.navigationItem.leftBarButtonItem = leftItem;



    NSDictionary* textAttributes = [NSDictionary dictionaryWithObject: [UIColor blackColor]
                                                               forKey: NSForegroundColorAttributeName];

    [[UIBarButtonItem appearance] setTitleTextAttributes: textAttributes
                                                forState: UIControlStateNormal];

    NSDictionary* textAttributes1 = [NSDictionary dictionaryWithObject: [UIColor brownColor]
                                                                forKey: NSForegroundColorAttributeName];
    [[UIBarButtonItem appearance] setTitleTextAttributes: textAttributes1
                                                forState: UIControlStateDisabled];

    NSDictionary* textAttributes2 = [NSDictionary dictionaryWithObject: [UIColor yellowColor]
                                                                forKey: NSForegroundColorAttributeName];
    [[UIBarButtonItem appearance] setTitleTextAttributes: textAttributes2
                                                forState: UIControlStateSelected];
}

- (void)viewDidLoad {
    [super viewDidLoad];
    [self setNaviagtionItem];

    self.navigationItem.leftBarButtonItem.enabled = NO;
}