swift :类提取后未调用UIPickerViewController委托

Question

我在一个应用程序上工作，这需要用户采取自拍图像从不同的ViewController。为了这个目的，我想提取类。但是在提取类之后，UIPickerViewController的delegate方法不会被调用。

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 
    }

将显示用于从图库中挑选图片的视图。但是当我选择图像时，视图控制器只是默默地不高兴，它的委托也不会被调用。

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

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

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

我已经挠头一整天了，但我还是不知道发生了什么事。

Answer 1

这些代码没有任何问题。问题在于它的命名方式。

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

每次调用函数时，我都会创建mediaManager的新局部变量。卸下mediaManager前面的var解决了问题。