an image is worth a thousand word, please see the attached image. This is a mobile app that I am developing. There is visually that thin line between the navigation bar and search bar, but I have tried everything I can think of, as well as everything that ChatGPT suggested but I still can’t remove that line. Any out-of-the-box idea what I might be overlooking? How can I remove that thin line?

Edited: (Since some of you asked me of the codes, here they are, although as I said they are quite lengthy so I am not sure if that’s helpful…)

On AppDelegate (this method is called on each view controller under viewDidAppear):

extension UINavigationController{

func setupWhiteTintColor(){
    if #available(iOS 13.0, *) {
        let appearance = UINavigationBarAppearance()
        appearance.configureWithDefaultBackground()
        appearance.backgroundColor = UIColor(hex: "#4CAF50")
        appearance.shadowColor = UIColor.clear
        appearance.shadowImage = UIImage()
        appearance.titleTextAttributes = [NSAttributedString.Key.foregroundColor : UIColor.white,.font : UIFont.boldSystemFont(ofSize: 20)]
        navigationBar.standardAppearance = appearance;
        navigationBar.scrollEdgeAppearance = appearance;
        navigationBar.compactAppearance = appearance;
        navigationBar.tintColor = UIColor.white
        navigationBar.setGradientBackground(colors: [UIColor(hex: "#388E3C"), UIColor(hex: "#4CAF50")], startPoint: .topLeft, endPoint: .bottomRight)
    } else {
        self.navigationBar.titleTextAttributes = [NSAttributedString.Key.foregroundColor : UIColor.white,.font : UIFont.boldSystemFont(ofSize: 20)]
        self.navigationBar.tintColor = UIColor.white
        self.navigationBar.barTintColor = UIColor(hex: "#4CAF50")
        self.navigationBar.isTranslucent = false
        self.navigationBar.setBackgroundImage(UIImage(), for: .default)
        self.navigationBar.shadowImage = UIImage()
    }
}

}

class UINavigationBarGradientView: UIView {

enum Point {
    case topRight, topLeft
    case bottomRight, bottomLeft
    case custom(point: CGPoint)

    var point: CGPoint {
        switch self {
            case .topRight: return CGPoint(x: 1, y: 0)
            case .topLeft: return CGPoint(x: 0, y: 0)
            case .bottomRight: return CGPoint(x: 1, y: 1)
            case .bottomLeft: return CGPoint(x: 0, y: 1)
            case .custom(let point): return point
        }
    }
}

private weak var gradientLayer: CAGradientLayer!

convenience init(colors: [UIColor], startPoint: Point = .topLeft,
                 endPoint: Point = .bottomLeft, locations: [NSNumber] = [0, 1]) {
    self.init(frame: .zero)
    let gradientLayer = CAGradientLayer()
    gradientLayer.frame = frame
    layer.addSublayer(gradientLayer)
    self.gradientLayer = gradientLayer
    set(colors: colors, startPoint: startPoint, endPoint: endPoint, locations: locations)
    backgroundColor = .clear
}

func set(colors: [UIColor], startPoint: Point = .topLeft,
         endPoint: Point = .bottomLeft, locations: [NSNumber] = [0, 1]) {
    gradientLayer.colors = colors.map { $0.cgColor }
    gradientLayer.startPoint = startPoint.point
    gradientLayer.endPoint = endPoint.point
    gradientLayer.locations = locations
}

func setupConstraints() {
    guard let parentView = superview else { return }
    translatesAutoresizingMaskIntoConstraints = false
    topAnchor.constraint(equalTo: parentView.topAnchor).isActive = true
    leftAnchor.constraint(equalTo: parentView.leftAnchor).isActive = true
    parentView.bottomAnchor.constraint(equalTo: bottomAnchor).isActive = true
    parentView.rightAnchor.constraint(equalTo: rightAnchor).isActive = true
}

override func layoutSubviews() {
    super.layoutSubviews()
    guard let gradientLayer = gradientLayer else { return }
    gradientLayer.frame = frame
    superview?.addSubview(self)
}

}

extension UINavigationBar {
    func setGradientBackground(colors: [UIColor],
                               startPoint: UINavigationBarGradientView.Point = .topLeft,
                               endPoint: UINavigationBarGradientView.Point = .bottomLeft,
                               locations: [NSNumber] = [0, 1]) {
        guard let backgroundView = value(forKey: "backgroundView") as? UIView else { return }
        guard let gradientView = backgroundView.subviews.first(where: { $0 is UINavigationBarGradientView }) as? UINavigationBarGradientView else {
            let gradientView = UINavigationBarGradientView(colors: colors, startPoint: startPoint,
                                                           endPoint: endPoint, locations: locations)
            backgroundView.addSubview(gradientView)
            gradientView.setupConstraints()
            return
        }
        gradientView.set(colors: colors, startPoint: startPoint, endPoint: endPoint, locations: locations)
    }
}

extension UITabBar {
    func setGradientBackground(colors: [UIColor],
                               startPoint: UINavigationBarGradientView.Point = .topLeft,
                               endPoint: UINavigationBarGradientView.Point = .bottomLeft,
                               locations: [NSNumber] = [0, 1]) {
        guard let backgroundView = value(forKey: "backgroundView") as? UIView else { return }
        guard let gradientView = backgroundView.subviews.first(where: { $0 is UINavigationBarGradientView }) as? UINavigationBarGradientView else {
            let gradientView = UINavigationBarGradientView(colors: colors, startPoint: startPoint,
                                                           endPoint: endPoint, locations: locations)
            backgroundView.addSubview(gradientView)
            gradientView.setupConstraints()
            return
        }
        gradientView.set(colors: colors, startPoint: startPoint, endPoint: endPoint, locations: locations)
    }
}

On each View Controller the following function is run:

func setupNavigationBarTitleView() {
    let imageView = UIImageView(image: UIImage(named: "TransparentToyzone"))
    imageView.contentMode = .scaleAspectFit
    
    // Set the height constraint to 30 pixels
    imageView.translatesAutoresizingMaskIntoConstraints = false
    NSLayoutConstraint.activate([
        imageView.heightAnchor.constraint(equalToConstant: 30)
    ])
    
    // Set the image view as the title view of the navigation bar
    self.navigationItem.titleView = imageView
}