将CustomView添加到navigationItem后，CustomView始终返回nil

Question

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

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

您需要定义视图，请检查以下简单示例：

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