ios - 从其他类访问 TabBarController 中的方法

Question

我花了最后几个小时来解决这个问题，但没有任何帮助。我的 LocationHelper 委托(delegate)如下所示:

func locationManager(_ manager: CLLocationManager,didChangeAuthorization status: CLAuthorizationStatus) {
        switch status {
        case .notDetermined:
            print("not terminated")
            break
        case .authorizedWhenInUse, .authorizedAlways:
            NavigationBarController().checkLocationBasedElements(result: 1)

            print("auth okay")
            break
        case .restricted, .denied:
            NavigationBarController().checkLocationBasedElements(result: 2)
            print("auth denied")
            break
        }
    }

当授权状态发生变化时，我可以在控制台上正确地看到打印输出。我的 NavigationBarController.checkLocationBasedElements 看起来像这样:

func checkLocationBasedElements(result: Int) -> Void{
        if(result == 2){
            print("checklocation: 2")
            tabBar.items?[1].isEnabled = false
            tabBar.items?[2].isEnabled = false
        }
        if(result == 1){
            //auth ok
            print("checklocation: 1")
            tabBar.items?[1].isEnabled = true
            tabBar.items?[2].isEnabled = true
        }

    }

当用户将 auth-status 更改为 .authorizedWhenInUse 时，控制台会给出以下输出:

checklocation: 1
auth okay

因此可以说方法被正确调用。但 tabBar 不会将 isEnabled 更改为 true 或 false。我尝试了很多事情，例如将逻辑放入 NavigationBarControllers 的 viewDidLoad 中或每次打开应用程序时检查权限状态，但这不是一个非常优雅的解决方案，因此我实现了委托(delegate)。我是否必须实例化 NavigationBarController，否则就像我所做的那样，或者您会推荐什么？

提前致谢!编辑:导航栏 Controller :

import UIKit

class NavigationBarController: UITabBarController {

    //let locationHelper = LocationHelper()
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.


        let iconSize = CGSize(width: 35, height: 35)
        let iconUnselected = UIColor.white
        let iconSelected = UIColor.gray

        //Start
        tabBar.items?[0].title = "Start"
        tabBar.items?[0].setFAIcon(icon: .FAHome, size: iconSize, textColor: iconUnselected, backgroundColor: .clear, selectedTextColor: iconSelected, selectedBackgroundColor: .clear)

        //Live
        tabBar.items?[1].title = "Live"
        tabBar.items?[1].setFAIcon(icon: .FATachometer, size: iconSize, textColor: iconUnselected, backgroundColor: .clear, selectedTextColor: iconSelected, selectedBackgroundColor: .clear)

        //Messen
        tabBar.items?[2].title = "Messen"
        tabBar.items?[2].setFAIcon(icon: .FAClockO, size: iconSize, textColor: iconUnselected, backgroundColor: .clear, selectedTextColor: iconSelected, selectedBackgroundColor: .clear)

        //Ergebnisse
        tabBar.items?[3].title = "Ergebnisse"
        tabBar.items?[3].setFAIcon(icon: .FAWindowRestore, size: iconSize, textColor: iconUnselected, backgroundColor: .clear, selectedTextColor: iconSelected, selectedBackgroundColor: .clear)



        //Check GPS Permission
        //self.checkLocationBasedElements(result: LocationHelper.shared.checkStatus())


    }
    func checkLocationBasedElements(result: Int) -> Void{
        //look above

    }

Answer 1

对于您当前的设计，最快的解决方案是:

1. 您的 LocationHelper 应声明 NavigationBarController

   的实例

   class LocationHelper {
       //...
       weak var myTabBarController: NavigationBarController?
       //...
   }
   

2. myTabBarController 应从 NavigationBarController 设置一次:

   class NavigationBarController: UITabBarController {
   
       override func viewDidLoad() {
           super.viewDidLoad()
           // Do any additional setup after loading the view, typically from a nib.
   
           LocationHelper.shared.myTabBarController = self
   
           //...
       }
   
   }
   

3. 您的 locationManager(_ manager:didChangeAuthorization:) 应调用

   myTabBarController?.checkLocationBasedElements(result:)
   

   而不是

   NavigationBarController().checkLocationBasedElements(result:)
   

   即

   func locationManager(_ manager: CLLocationManager,didChangeAuthorization status: CLAuthorizationStatus) {
       switch status {
       case .notDetermined:
           print("not terminated")
       case .authorizedWhenInUse, .authorizedAlways:
           myTabBarController?.checkLocationBasedElements(result: 1)
   
           print("auth okay")
       case .restricted, .denied:
           myTabBarController?.checkLocationBasedElements(result: 2)
           print("auth denied")
       }
   }
   

基本上，当您执行 NavigationBarController().checkLocationBasedElements(result:) 时，您正在 NavigationBarController 的新实例上运行 checkLocationBasedElements(result:) > 这与包含您看到的选项卡的不同。