未设置UINavigationBar contentMode

Question

我正在尝试使UINavigationBar的背景成为一个图像，而该图像并不是条形图的确切大小。由于某些原因，我似乎无法正确设置工具栏的contentMode。这是我的代码：

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)

    // ...


    let image = UIImage(named: object?.imageName ?? "")
    navigationController?.navigationBar.alpha = 0
    navigationController?.navigationBar.setBackgroundImage(image, for: .default)
    self.navigationController?.navigationBar.contentMode = .scaleAspectFill
    UIView.animate(withDuration: Double(UINavigationControllerHideShowBarDuration), animations: {
        self.navigationController?.navigationBar.alpha = 1
    })
}

我不知道我做错了什么，或者也许contentMode根本没有为UINavigationBar做任何事情。

当前发生的情况是背景图像只是像马赛克一样再次呈现

谢谢

Answer 1

您可以创建UIView并向其中添加图像和文本，但必须设置约束

    let titleView = UIView()
    titleView.frame = CGRect(x: 0, y: 0, width: 100, height: 40)

    let containerView = UIView()
    containerView.translatesAutoresizingMaskIntoConstraints = false

    titleView.addSubview(containerView)

    let profileImageView = UIImageView()
    profileImageView.translatesAutoresizingMaskIntoConstraints = false
    profileImageView.contentMode = .scaleAspectFill
    profileImageView.layer.cornerRadius = 20
    profileImageView.clipsToBounds = true
    containerView.addSubview(profileImageView)

    profileImageView.leftAnchor.constraint(equalTo: containerView.leftAnchor).isActive = true
    profileImageView.centerYAnchor.constraint(equalTo: containerView.centerYAnchor).isActive = true
    profileImageView.widthAnchor.constraint(equalToConstant: 40).isActive = true
    profileImageView.heightAnchor.constraint(equalToConstant: 40).isActive = true

    self.navigationItem.titleView = titleView

    titleView.addGestureRecognizer(UITapGestureRecognizer(target: 
    self, action: #selector(func)))

我希望我能帮到你