new version

#import <UIKit/UIKit.h>

@interface AVCNavigationController : UINavigationController

- (void)setNavBarBackgroundVisible:(BOOL)navBarVisible animated:(BOOL)animated;

@property (nonatomic)   BOOL    navBarBackgroundVisible;

/// should be called from viewWillAppear(); 'vc' is an optional parameters
- (void)setBackgroundColor:(UIColor *)barTint animatedUsing:(UIViewController *)vc;

- (UIColor *)previousBarTintColor;

@end







#import "AVCNavigationController.h"

#import "UIImage+ImageWithColor.h"
#import "UIColor+AVCColors.h"

@interface AVCNavigationController ()

@property (nonatomic)   UIColor *   barTintColor;   //!< last set bar tint color, gets pushed onto the stack in pushViewController()

@property (nonatomic)   NSMutableArray< UIColor* >  *   barTintColorStack;  //!< so that we can peek at previous bar tint color for smooth transitions

@end

@implementation AVCNavigationController

+ (void)initialize
{
    [[UINavigationBar appearance] setBarTintColor:[UIColor avc_greenColor]];
    [[UINavigationBar appearance] setTranslucent:NO];
}

- (void)viewDidLoad
{
    [super viewDidLoad];

    self.navigationBar.translucent = NO;

    _barTintColor = [UIColor avc_greenColor];
    _barTintColorStack = [NSMutableArray< UIColor* > arrayWithCapacity:4];
}

- (void)setNavBarBackgroundVisible:(BOOL)navBarBackgroundVisible
{
    [self setNavBarBackgroundVisible:navBarBackgroundVisible animated:NO];
}

- (void)setNavBarBackgroundVisible:(BOOL)navBarBackgroundVisible animated:(BOOL)animated
{
    _navBarBackgroundVisible = navBarBackgroundVisible;
    printf("❤️INFO: setNavBarBackgroundVisible: %d, animated=%d\n",navBarBackgroundVisible, animated);
}

- (void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated
{
    [_barTintColorStack addObject:_barTintColor];

    [super pushViewController:viewController animated:animated];
}

- (nullable UIViewController *)popViewControllerAnimated:(BOOL)animated
{
    UIViewController *vc = [super popViewControllerAnimated:animated];

    [_barTintColorStack removeLastObject];

    return vc;
}

- (void)setBackgroundColor:(UIColor *)barTint animatedUsing:(UIViewController *)vc
{
    _barTintColor = barTint;

    if( vc )
    {
        [vc.transitionCoordinator animateAlongsideTransition:^(id<UIViewControllerTransitionCoordinatorContext> context) {
            //
            self.navigationBar.barTintColor = barTint;

        } completion: nil];
    }
    else
    {
        self.navigationBar.barTintColor = barTint;
    }
}

- (UIColor *)previousBarTintColor
{
    NSAssert(_barTintColorStack.count, @"empty stack!");

    UIColor *previousColor = _barTintColorStack.lastObject;

    return previousColor;
}

- (UIColor *)currentBarTintColor
{
    return _barTintColorStack.lastObject;
}

@end