rightBarButtonItem 图像未显示

Question

谁能帮我理解我的代码有什么问题。我没有得到它，我的代码编译得很好，没有任何错误，但我的图像没有显示出来。我确信我的图像存在于 Assests 文件夹中，并且我也给出了我的图像的正确名称。我正在以编程方式进行操作。以下是我的代码-：

*AppDelegate-:

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        // Override point for customization after application launch.
        windowLayout()
        application.statusBarStyle = .lightContent
        return true
    }

    func windowLayout()
    {
        window = UIWindow(frame: UIScreen.main.bounds)
        window?.makeKeyAndVisible()

        let layout = UICollectionViewFlowLayout()
        window?.rootViewController = UINavigationController(rootViewController: HomeController(collectionViewLayout: layout))
        UINavigationBar.appearance().barTintColor = UIColor(colorLiteralRed: 238/255, green: 32/255, blue: 31/255, alpha: 1)
        let statusBarView = UIView()
        statusBarView.backgroundColor = UIColor(colorLiteralRed: 194/255, green: 31/255, blue: 31/255, alpha: 1)
        window?.addSubview(statusBarView)
        window?.translatesAutoresizingMaskIntoConstraints = false
        //window?.addConstraintsWithFormat(format: "H:|[v0]|", views: statusBarView)
        //window?.addConstraintsWithFormat(format: "V:|[v0(20)]", views: statusBarView)
        UINavigationBar.appearance().shadowImage = UIImage()
        //UINavigationBar.appearance().setBackgroundImage(UIImage(),forBarMatrics: .default)
    }

扩展文件-：

import UIKit


protocol navigationBarItems {
    func searchBarButton()
    func handleMoreButton()
}


extension UINavigationController:navigationBarItems
{
    func handleMoreButton() {

    }

    func searchBarButton()
    {
        let searchBarImage = UIImage(named: "search-icon")?.withRenderingMode(UIImageRenderingMode.alwaysTemplate)
        let searchImage = UIBarButtonItem(image: searchBarImage, style: UIBarButtonItemStyle.done, target: self, action: #selector(handleSearch))
        navigationItem.rightBarButtonItem = searchImage

    }

    func handleSearch()
    {
        print("123")
    }

}

控制器类-：

class HomeController: UICollectionViewController,UICollectionViewDelegateFlowLayout {

    override func viewDidLoad() {
        super.viewDidLoad()
        setUpLayout()
        setUpMenuBar()
        fetchJsonData()
        navigationController?.searchBarButton()
    }

我已经通过设置断点来检查我的函数是否被调用进行了测试。它工作正常，但图像没有显示请帮助。

Answer 1

尝试扩展 UIViewController 而不是 UINavigationController

extension UIViewController:navigationBarItems
{
    func handleMoreButton() {

    }

    func searchBarButton()
    {
        let searchBarImage = UIImage(named: "search-icon")?.withRenderingMode(UIImageRenderingMode.alwaysTemplate)
        let searchImage = UIBarButtonItem(image: searchBarImage, style: UIBarButtonItemStyle.done, target: self, action: #selector(handleSearch))
        navigationItem.rightBarButtonItem = searchImage

    }

    func handleSearch()
    {
        print("123")
    }

}

现在从`viewDidLoad`调用这个方法

class HomeController: UICollectionViewController,UICollectionViewDelegateFlowLayout {

    override func viewDidLoad() {
        super.viewDidLoad()
        setUpLayout()
        setUpMenuBar()
        fetchJsonData()
        self.searchBarButton()
    }