Issue with presenting UIDocumentInteractionController in a custom class

Question

I created a custom class named PreviewFile:

class PreviewFile: UIViewController , UIDocumentInteractionControllerDelegate {

     var documentInteractionController = UIDocumentInteractionController()


    func previewFile(name:String)  {

        let documentsURL = NSURL(fileURLWithPath: NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true).first!,isDirectory: true )
        let urlToMyPath = documentsURL.appendingPathComponent(name)!

        documentInteractionController = UIDocumentInteractionController(url: urlToMyPath)
        documentInteractionController.delegate = self
        documentInteractionController.presentPreview(animated: true)

    }



    public  func documentInteractionControllerViewControllerForPreview(_ controller: UIDocumentInteractionController) -> UIViewController {

        return self

    }

}

Then I call the previewFile method on a ViewController :

var preview = PreviewFile()
preview.previewFile(name:"guide.pdf")

But compiler gives me this error :

Warning: Attempt to present on whose view is not in the window hierarchy!

What you are doing here from this line var preview = PreviewFile() this line only take copy of the class but not the View attached to that class. try let storyboard = UIStoryboard(name: "MyStoryboardName", bundle: nil) let controller = storyboard.instantiateViewController(withIdentifier: "someViewController") as! yourViewControllerClass and call like this controller.previewFile(name:"guide.pdf") — elk_cloner
– elk_cloner, Commented May 23, 2017 at 12:05

Naveed Ahmad · Accepted Answer · 2019-03-27 07:20:37Z

class PreviewFile: UIViewController , UIDocumentInteractionControllerDelegate {

    private var controller: UIViewController!

    func previewFile(name:String, in controller: UIViewController)  {
        self.controller = controller
        let documentsURL = NSURL(fileURLWithPath: NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true).first!,isDirectory: true )
        let urlToMyPath = documentsURL.appendingPathComponent(name)!

        let documentInteractionController = UIDocumentInteractionController(url: urlToMyPath)
        documentInteractionController.delegate = self
        documentInteractionController.presentPreview(animated: true)

    }



    public func documentInteractionControllerViewControllerForPreview(_ controller: UIDocumentInteractionController) -> UIViewController {

        return self.controller

    }

}

then you will be able to call it from UIViewController like that:

var preview = PreviewFile()
preview.previewFile(name:"guide.pdf", in self)

You have this issue because you are trying to show documentDirectory from PreviewFile controller, what is not presented on screen

UPDATE #1 Better solution

class PreviewFile: NSObject, UIDocumentInteractionControllerDelegate {
private var controller: UIViewController!

init(controller: UIViewController) {
    super.init()
    self.controller = controller
}

func previewFile(name:String)  {
    let documentsURL = NSURL(fileURLWithPath: NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true).first!,isDirectory: true )
    let urlToMyPath = documentsURL.appendingPathComponent(name)!

    let documentInteractionController = UIDocumentInteractionController(url: urlToMyPath)
    documentInteractionController.delegate = self
    documentInteractionController.presentPreview(animated: true)
}


public func documentInteractionControllerViewControllerForPreview(_ controller: UIDocumentInteractionController) -> UIViewController {

    return self.controller

}
}

call it like that:

var preview = PreviewFile(controller: self)
preview.previewFile(name:"guide.pdf")

Collectives™ on Stack Overflow

Issue with presenting UIDocumentInteractionController in a custom class

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related