从Swift中的另一个ViewController访问rightBarButton函数

Posted 2021-05-07

我正在尝试访问rightBarButton功能，显示来自另一个ViewController的购物车，虽然我可以调用该功能，但它不会显示任何图像，即购物车图像

下面的代码显示了我如何调用此函数。

override func viewDidLoad() {
            super.viewDidLoad()
            // Adding Right Bar Button Item
            let rightBarButton = RightBarButton()
            rightBarButton.addingRightButton()
    }

下面的代码显示了rightBarButton函数。

class RightBarButton {

    var storyboard = UIStoryboard()
    var navigationItem = UINavigationItem()
    var navigationController = UINavigationController()

    func addingRightButton() {

        let image = UIImage(named: "cart") 

        let finalImage = resizeImage(image: image!, newWidth: 30)

        navigationItem.rightBarButtonItem = FFBadgedBarButtonItem(image: finalImage, target: self, action: #selector(rightButtonTouched))

        let button = navigationItem.rightBarButtonItem as? FFBadgedBarButtonItem

        cartCount { (cartCount) in
            print("Api calling done ...")
            print(cartCount)
            button?.badge = "\(cartCount)"
        }
    }

    @objc func rightButtonTouched() {
        // print("Event Called")
    }

    func cartCount(completion: @escaping (Int) -> Void) {
        // print("Api calling ...")
    }
}

如果我在viewDidLoad()中添加此代码，则会显示图像，并且click事件也会起作用。

如果您找到有关此代码的任何解决方案，请帮忙！

答案

它不起作用，因为navigationItem类中的RightBarButton不属于任何导航控制器（因为它是手动创建的，未明确附加）。

使创建的FFBadgedBarButtonItem实例可供视图控制器访问，以便您可以正确添加它：

override func viewDidLoad() {
    super.viewDidLoad()
    // Adding Right Bar Button Item
    let rightBarButton = RightBarButton()
    rightBarButton.addingRightButton()

    navigationItem.rightBarButtonItem = rightBarButton.badgeBarItem // badgeBarItem is the property exposed to the view controller
}

编辑过的RightBarButton课程：

class RightBarButton {

    var badgeBarItem: FFBadgedBarButtonItem?

    func addingRightButton() {

        let image = UIImage(named: "cart")

        let finalImage = resizeImage(image: image!, newWidth: 30)

        badgeBarItem = FFBadgedBarButtonItem(image: finalImage, target: self, action: #selector(rightButtonTouched))

        cartCount { [weak self] cartCount in
            print("Api calling done ...")
            print(cartCount)
            self?.badgeBarItem?.badge = "\(cartCount)"
        }
    }

    @objc func rightButtonTouched() {
        // print("Event Called")
    }

    func cartCount(completion: @escaping (Int) -> Void) {
        // print("Api calling ...")
    }
}

另一答案

ViewController说，你需要用rightBarButton来检索所需的neededViewController实例。然后你可以这样称呼它：

neededViewController.viewDidLoad()

或者在neededViewController的课堂上使用下一个内容制作另一种方法：

func addRB () {
// let rightBarButton = RightBarButton(image: UIImage(named: "imageName"), landscapeImagePhone: UIImage(named: "imageName"), style: .done, target: self, action: nil)   

   let nc = navigationController
   let navBar = nc?.navigationBar

   let but = UIBarButtonItem(image: UIImage(named: "imageName"), landscapeImagePhone: UIImage(named: "imageName"), style: .done, target: self, action: nil)

// try to create RightBarButton with defined images and a text and pass it instead of `but`
   navBar?.topItem?.setRightBarButton(but, animated: false)
}

并致电neededViewController.addRB()