ios - 无法以编程方式添加栏按钮项

Question

func myPlaceViewMoreWasPressed() {
    print("myPlaceViewMore was pressed")

    let vc = MyPlacesViewController(nil)
    let nav = UINavigationController(rootViewController: vc)
    let dismissButton = UIBarButtonItem.init(title: "Dismiss", style: .plain, target: self, action: #selector(dismissButtonWasPressed))
    nav.navigationItem.leftBarButtonItem = dismissButton

    self.present(nav, animated: true, completion: nil)
}

应该非常简单...实例化一个 ViewController，将其包含在导航 Controller 中，初始化一个 UIBarButtonItem 并将其设置为导航的 leftBarButtonItem。我也试过这样:

func myPlaceViewMoreWasPressed() {
    print("myPlaceViewMore was pressed")

    let vc = MyPlacesViewController(nil)
    let nav = UINavigationController(rootViewController: vc)
    let dismissButton = UIBarButtonItem.init(title: "Dismiss", style: .plain, target: self, action: #selector(dismissButtonWasPressed))
    nav.navigationItem.setLeftBarButton(dismissButton, animated: true)

    self.present(nav, animated: true, completion: nil)
}

但是按钮不会出现。

Answer 1

您需要更新 View Controller 的 navigationItem，而不是导航 Controller 。我会在将 View Controller 设置为根 Controller 之前这样做。

func myPlaceViewMoreWasPressed() {
    print("myPlaceViewMore was pressed")

    let vc = MyPlacesViewController(nil)
    let dismissButton = UIBarButtonItem.init(title: "Dismiss", style: .plain, target: self, action: #selector(dismissButtonWasPressed))
    vc.navigationItem.leftBarButtonItem = dismissButton

    let nav = UINavigationController(rootViewController: vc)

    self.present(nav, animated: true, completion: nil)
}