如何将UIBarButtonItem文本强制为特定颜色？

Question

我在导航栏上有一个UIBarButtonItem。当我进入我的应用程序时，它开始白色（所需的颜色），然后突然切换为淡出的灰色。如果我与应用程序交互并稍后返回到同一视图控制器，则按钮将返回白色。可能导致这种情况的原因是什么？

- (void)viewDidLoad
    {
        [super viewDidLoad];
        // Do any additional setup after loading the view.
        UIBarButtonItem *backButton = [[UIBarButtonItem alloc] initWithTitle:@"Logout" style:UIBarButtonItemStyleDone target:self action:@selector(handleBack:)];
        [backButton setTitleTextAttributes:[NSDictionary dictionaryWithObject: [UIColor whiteColor]
                                                                      forKey: UITextAttributeTextColor] forState:UIControlStateNormal];
        //[backButton setTintColor: [UIColor whiteColor]];
        self.navigationItem.leftBarButtonItem = backButton;
        [self.navigationController.navigationBar setBarStyle: UIBarStyleBlack];
        [self populateSpinners];
        isCategoryPicker = true;
        [self.view setTintAdjustmentMode:UIViewTintAdjustmentModeNormal];
    }

我尝试在视图级别，工具栏级别和按钮级别设置色调颜色，似乎没有任何效果。任何帮助表示赞赏！