将CustomView添加到navigationItem之后，CustomView始终返回nil [英] After Add a CustomView to navigationItem, CustomView always return nil

问题描述

下面的代码成功地将一个customView添加到navigationItem，但是当尝试访问customView时，它总是返回nil

Bellow code is adding a customView to navigationItem successfully, but when trying to access the customView it always return nil

override func viewDidLoad() {
    super.viewDidLoad()
    let customView = getCustomView() // supposed that the function return a custom view
    let actionButton = UIBarButtonItem(customView: customView)
    self.navigationItem.rightBarButtonItem = actionButton // successfully added customView
    print(navigationItem.rightBarButtonItem?.customView)  // print always nil
}

结果:

nil

推荐答案

我发现访问customView(自定义rightBarButtonItem)的最佳方法是，我们必须通过Swift标准方式进行访问:

I found out that the best way to access our customView (custom rightBarButtonItem), we have to access through Swift standard way:

添加customView后，我们只能通过self.navigationItem.rightBarButtonItems数组访问customView.

After adding the customView, we can access the customView via : self.navigationItem.rightBarButtonItems array only.

就我而言，要从navigationItem取回customView:

In my case to get customView back from navigationItem :

let customView = navigationItem.rightBarButtonItems?.first?.customView//访问第一个 添加了customView

let customView = navigationItem.rightBarButtonItems?.first?.customView // access the first added customView

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