ios - swift : UIPickerViewController delegates not called after Class-Extraction

Question

我正在开发一个应用程序，该应用程序要求用户对来自不同 ViewController 的图片进行自拍。我想为此目的提取类。但是在提取类之后，UIPickerViewController 的delegate 方法没有被调用。

现在，我在 MultiMediaManager.swift 文件中有一个名为 MultiMediaManager 的类。

    class MultiMediaManager: NSObject, UIImagePickerControllerDelegate, UINavigationControllerDelegate {


    let imagePicker = UIImagePickerController()
    var viewController: UIViewController?
    var delegate: MultiMediaManagerDelegate?

    init(presentingViewController: UIViewController) {
        viewController = presentingViewController
        super.init()
        imagePicker.delegate = self
    }

    func showPictureSourceOptions() {
        var presentationStyle: UIAlertControllerStyle = .ActionSheet
       let galleryAction = UIAlertAction(title: "Photo Library", style: UIAlertActionStyle.Default) { (action) in
            self.showPhotoGallery()
        }
        alertController.addAction(galleryAction)
        self.viewController?.presentViewController(alertController, animated: true, completion: nil)
    }

    private func showPhotoGallery() {
        imagePicker.allowsEditing = false
        imagePicker.sourceType = .PhotoLibrary
        viewController?.presentViewController(imagePicker, animated: true, completion: nil)

      // every thing is working till here as expected.
     // note: here, debugger prints MultiMediaManager as imagePicker.delegate 
    }

显示从图库中选择图片的 View 。但是当我选择图像时，viewcontroller 只是默默地关闭并且它的委托(delegate)没有被调用。

    func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : AnyObject]) {

    // break point does not stop here. nither print statement work.

      viewController?.dismissViewControllerAnimated(true, completion: nil)
}

一整天都在摸不着头脑，但我仍然不知道发生了什么。

Answer 1

这些代码没有任何问题。问题在于它的调用方式。

func showPictureSourceOptions() {
        var mediaManager = MultiMediaManager(presentingViewController: self)
        mediaManager!.showPictureSourceOptions()
    }

每次调用该函数时，我都在创建 mediaManager 的新局部变量。删除 mediaManager 前面的 var 解决了这个问题。