swift:Class-Extraction之后未调用UIPickerViewController委托 [英] swift : UIPickerViewController delegates not called after Class-Extraction

问题描述

我正在开发一个应用程序，该应用程序要求用户从不同的ViewController拍摄自选图像的自拍照.我只想为此提取类.但是，在提取类之后，不会调用 UIPickerViewController 的 delegate 方法.

I am working on an app which requires user to take selfie of pick Images from different ViewController. I want to extract class just for this purpose. But after extraction of class the delegate methods of UIPickerViewController are not being called.

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

right now, I have a class called MultiMediaManager inside MultiMediaManager.swift file.

    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 
    }

显示了从图库中选择图片的视图.但是，当我选择图像时，视图控制器只是默默关闭，并且不会调用其委托.

The View to pick and choose the picture from gallery is presented. But When I choose image, the viewcontroller just dissmiss silently and its delegate is not called.

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

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

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

我整天都在挠头，但是我仍然不知道发生了什么.

I have been scratching my head the whole day, But I still don't have any idea what's going on.

推荐答案

这些代码没有错.问题是它的调用方式.

There was nothin wrong with these code. The problem was the way it was called.

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

每次调用该函数时，我都会创建一个新的 mediaManager 局部变量.删除 var 在 mediaManager 前面解决了该问题.

I was creating new local variable of mediaManager every time the function was called. removing the var In front of the mediaManager fixed the problem.

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