将自定义视图添加到导航项后，自定义视图始终 return nil

Question

下面的代码成功地向 navigationItem 添加了一个 customView，但是当试图访问 customView 时它总是 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

Answer 1

let customView = UIView(frame: CGRect(x: 0, y: 0, width: 100, height: 100))
    customView.backgroundColor = UIColor.blue// supposed that the function return a custom view
    let actionButton = UIBarButtonItem(customView: customView)
    self.navigationItem.rightBarButtonItem = actionButton // successfully added customView
    print(navigationItem.rightBarButtonItem?.customView)

这对我有用

Answer 2

我发现访问我们的 customView（自定义 rightBarButtonItem）的最佳方式，我们必须通过 Swift 标准方式访问：

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

在我的例子中，要从 navigationItem 取回 customView：

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

将自定义视图添加到导航项后，自定义视图始终 return nil

After Add a CustomView to navigationItem, CustomView always return nil

ios

swift

iphone

uinavigationbar

custom-view