ios - 无法将类型 'Class' 的值分配给类型 'protocol?'

Question

我希望之前有人遇到过这个问题。我正在尝试将此类指定为 UIImagePickerController 的委托(delegate)，但出现此错误:

“PictureViewController.swift:40:32:无法将类型‘PictureViewController’的值分配给类型‘协议(protocol)？’”

有什么想法吗？提前致谢。

import UIKit
import MVCarouselCollectionView
import Eureka
import RealmSwift

public class PictureViewController<T: Equatable>: FormViewController, TypedRowControllerType,
            MVCarouselCollectionViewDelegate, UIImagePickerControllerDelegate{

    public var row: RowOf<T>!
    public var completionCallback : ((UIViewController) -> ())?
    let imagePicker = UIImagePickerController()

    public override func viewDidLoad() {
        super.viewDidLoad()
        self.navigationItem.setRightBarButtonItem(
        UIBarButtonItem(barButtonSystemItem: .Add, target: self, action: "loadImageButtonTapped:"), animated: true)

        imagePicker.delegate = self  <<<==== THIS GIVES ERROR MESSAGE
}

Answer 1

其实我已经明白了。我还必须声明该类实现了 UINavigationControllerDelegate 并且现在一切正常。