iOS navigationItem.RightBarButtonim未响应其选择器

我从a继承了一个超类a和一个子类B。我想表示B。在类a中添加navigationItem.RightBarButtonim时，选择器没有响应其选择器

class A: UIViewController {

var saveNaviBtn: UIBarButtonItem = UIBarButtonItem(title: "save", style: .done, target: self, action: #selector(save))    

@objc func save() {
    dismiss(animated: true)
}

override func viewDidLoad() {
    super.viewDidLoad()
    self.navigationItem.rightBarButtonItem = saveNaviBtn

}
}
class B: A {

}

---

我认为出于某种原因，当Barbuttonite初始化时，它的目标self可能没有完成初始化。这样做：

class A: UIViewController {
    var saveNaviBtn: UIBarButtonItem?

    override func viewDidLoad() {
        saveNaviBtn = UIBarButtonItem(title: "save", style: .done, target: self,      action: #selector(save))
        self.navigationItem.rightBarButtonItem = saveNaviBtn
    }
}

---

试着像你说的那样，你想在A班上展示B。但我看到你的代码是“驳回”。为什么？