Swift 3 - 将 rootviewcontroller 委托设置为导航控制器

Question

在我的 Swift 3/Obj-C 应用程序中，我试图将我的 rootviewcontroller 的委托设置为其导航控制器，但出现以下错误：

Cannot assign value of type 'NavController.Type' to type 'RootViewControllerDelegate'

NavController.swift

@available(iOS 10.0, *)
@objc class NavController: UINavigationController, RootViewControllerDelegate {

    static func instantiate() -> NavController? {
        let storyboard = UIStoryboard.init(name: "MyStoryboard", bundle: nil)
        let navVC = storyboard.instantiateViewController(withIdentifier: "NavController") as? NavController

        let rootVC = navVC?.viewControllers.first as! RootViewController
        rootVC.delegate = self // <<<< ERROR OCCURS HERE

        return navVC
    }

    func pressedNextButton()
    {
        NSLog("Next button works!")
    }
}

RootViewController.swift

@objc protocol RootViewControllerDelegate {
    func pressedNextButton()
}

@available(iOS 10.0, *)
@objc class RootViewController: UIViewController, NSFetchedResultsControllerDelegate, UITableViewDataSource, UITableViewDelegate {

    var delegate: RootViewControllerDelegate?

    @IBAction func nextButton(_ sender: UIBarButtonItem) {
        self.delegate?.pressedNextButton()
    }
}

MainProgram.m

@interface MYQAddDeviceViewController () 
     @property (nonatomic, strong) NavController * navVC;
@end

- (void)viewDidLoad
{
    [super viewDidLoad];
    self.navVC = [NavController instantiate];
}

关于如何解决该错误的任何想法？

Answer 1

您收到该错误是因为行

rootVC.delegate = self

位于 static func 中，在该上下文中，self 指的是 NavController 元类的实例，即 NavController.Type 而不是 NavController。

你想要：

if let navVC = storyboard.instantiateViewController(withIdentifier: "NavController") as? NavController,
    let rootVC = navVC.viewControllers.first as? RootViewController {

    rootVC.delegate = navVC
}

Swift 3 - 将 rootviewcontroller 委托设置为导航控制器

Swift 3 - setting rootviewcontroller delegate to navigation controller

delegates

objective-c

uinavigationcontroller

swift3

rootviewcontroller