ios - 在 UINavigationController 中设置图像时不显示图像

Question

我正在尝试构建一个分配给我的导航 Controller (在我的 Storyboard中)的 Cocoa Touch 类，以在导航栏的中心显示图像。该应用程序已构建，但图像未显示，我不明白为什么。

class NavBarImg: UINavigationController {


    required init(coder aDecoder: NSCoder){
        super.init(coder: aDecoder)!
        setupView()
    }

    func setupView(){
        if navigationController == nil {
            return
        }

        let image = #imageLiteral(resourceName: "BarTabsNavLogoWhite")
        let imageView = UIImageView(image: image)

        let bannerWidth = navigationBar.frame.size.width
        let bannerHeight = navigationBar.frame.size.height

        let bannerX = bannerWidth / 2 - image.size.width / 2
        let bannerY = bannerHeight / 2 - image.size.height / 2

        imageView.frame = CGRect(x: bannerX, y: bannerY, width: bannerWidth, height: bannerHeight)
        imageView.contentMode = .scaleAspectFit

        self.navigationItem.titleView = imageView  

    }
}

Answer 1

为 UINavigationController 创建一个 cocoa touch 类 > 实现下面的代码 > 将类分配给 Storyboard中的导航 Controller 。

class NavControllerClass: UINavigationController {

override func viewDidLoad() {
    super.viewDidLoad()
    setupNavigationBar()

}

func setupNavigationBar()
{
    let image = #imageLiteral(resourceName: "BarTabsNavLogoWhite")
    let imageView = UIImageView(image: image)
    imageView.frame = navigationBar.frame
    imageView.contentMode = .scaleAspectFit
    navigationBar.addSubview(imageView)
}

}