UINavigationBar styling between UINavigationController transitions

transition.m

- (void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];
    
    [[self transitionCoordinator] animateAlongsideTransition:^(id<UIViewControllerTransitionCoordinatorContext> context) {
        [self.navigationController.navigationBar setTintColor:[UIColor blackColor]];
        [self.navigationController.navigationBar setTitleTextAttributes:@{NSForegroundColorAttributeName: [UIColor blackColor]}];
        [self.navigationController.navigationBar setBackgroundImage:[UIImage imageNamed:@"bg_navbar"] forBarMetrics:UIBarMetricsDefault];
    } completion:nil];
}

- (void)viewWillDisappear:(BOOL)animated
{
    [super viewWillDisappear:animated];
    
    [[self transitionCoordinator] animateAlongsideTransition:^(id<UIViewControllerTransitionCoordinatorContext> context) {
        [self.navigationController.navigationBar setTintColor:[UIColor whiteColor]];
        [self.navigationController.navigationBar setTitleTextAttributes:@{NSForegroundColorAttributeName: [UIColor whiteColor]}];
        [self.navigationController.navigationBar setBackgroundImage:[[UIImage alloc] init] forBarMetrics:UIBarMetricsDefault];
    } completion:^(id<UIViewControllerTransitionCoordinatorContext>  _Nonnull context) {
        if ([context isCancelled]) {
            [self.navigationController.navigationBar setTintColor:[UIColor blackColor]];
            [self.navigationController.navigationBar setTitleTextAttributes:@{NSForegroundColorAttributeName: [UIColor blackColor]}];
            [self.navigationController.navigationBar setBackgroundImage:[UIImage imageNamed:@"bg_navbar"] forBarMetrics:UIBarMetricsDefault];
        }
    }];
}