How to implement UIDocumentInteractionController on iPad using Xamarin

Question

I'm using Xamarin to develop an iPad iOS 7.0 app and I want to use the UIDocumentInteractionController to display a PDF. I used various examples on Stack Overflow to get the proper implementation but nothing has worked.

Here is a link on Stack Overflow which I used for reference.

Monotouch open document - UIDocumentInterationController

I also used this objective C tutorial but have been unable to properly translate this code into C#. http://code.tutsplus.com/tutorials/previewing-and-opening-documents-with-uidocumentinteractioncontroller--mobile-15130

Here is my code. I currently have a toolbar button which, when clicked, should trigger the PDF preview. Nothing happens when I click the button.

What is it that I am missing for this to work?

public override void ViewDidLoad ()
{
    base.ViewDidLoad ();

    documentInteractionController = new UIDocumentInteractionController ();

    string fileName = "Content/test.pdf";
    string localURL = Path.Combine (NSBundle.MainBundle.BundlePath, fileName);
    NSUrl URL = new NSUrl(localURL, false);

    documentInteractionController = UIDocumentInteractionController.FromUrl (URL);
    documentInteractionController.Delegate = new UIDocumentInteractionControllerDelegateClass(this);

    toolbarButton.Clicked += delegate(object sender, EventArgs e){
        InvokeOnMainThread(delegate{
            documentInteractionController.PresentOpenInMenu(View.Frame, View, true);
        });
    };
}


public class UIDocumentInteractionControllerDelegateClass : UIDocumentInteractionControllerDelegate
{
    UIViewController viewC;

    public UIDocumentInteractionControllerDelegateClass(UIViewController controller)
    {
        viewC = controller;
    }

    public override UIViewController ViewControllerForPreview (UIDocumentInteractionController controller)
    {
        return viewC;
    }

    public override UIView ViewForPreview (UIDocumentInteractionController controller)
    {
        return viewC.View;
    }

    public override RectangleF RectangleForPreview (UIDocumentInteractionController controller)
    {
        return viewC.View.Frame;
    }
}

score 3 · Accepted Answer · edited May 23 '17 at 10:27

After researching this issue, asking the same question on another forum, and using different code examples, I am unable to get this code working using a UIDocumentInteractionController in C#. I can, however, get it working using the objective-c tutorial linked in the above question. This is not useful since I need the code in C# instead of objective-c.

During my research I found this post on Stack Overflow which instead used a QLPreviewController.

Monotouch - Issue with QLPreviewController

This code provides exactly what I need for my application. I made one change to the original location of the PDF and it works as expected.

Here is the code, taken and modified from the above post, I am using to open a PDF in a Quick Preview control which has the "Open In" functionality.

Here is the code for the controller:

QLPreviewController previewController= new QLPreviewController();             

previewController.DataSource=new MyQLPreviewControllerDataSource();     

this.PresentViewController(previewController,true, null);

Here is the code for the Data Source:

public class MyQLPreviewControllerDataSource : QLPreviewControllerDataSource { 

    public override int PreviewItemCount (QLPreviewController controller) {
        return 1;
    }

    public override QLPreviewItem GetPreviewItem (QLPreviewController controller, int index)
    {
        string fileName = @"example.pdf";
        var documents = NSBundle.MainBundle.BundlePath;
        var library = Path.Combine (documents,fileName);
        NSUrl url = NSUrl.FromFilename (library);
        return new QlItem ("Title", url);
    }
}

Here is the code for the QlItem:

public class QlItem : QLPreviewItem 
    { 
        string title; 
        NSUrl uri; 

        public QlItem(string title, NSUrl uri) 
        { 
            this.title = title; 
            this.uri = uri; 
        } 

        public override string ItemTitle { 
            get { return title; } 
        } 

        public override NSUrl ItemUrl { 
            get { return uri; } 
        } 
    }

can you detect if the user chooses to open the file on an external app? — nhenrique, May 18 '15 at 08:43
@nhenrique It is my understanding the apps on iOS cannot talk to each other which is by design. In that regard, it would not be possible to detect if the user chooses to open the file on an external app. If it is possible, then I, as well, would like to know how it is done. — Shawn Roser, May 18 '15 at 19:15
Hi @ShawnRoser , please have a look at this http://stackoverflow.com/questions/30298405/detect-when-user-opens-file-in-app/30304547#30304547 .You can detect which app the user chooses and perhaps show a loading until the event didEndSendingToApplication is called — nhenrique, May 19 '15 at 08:17

score 1 · Answer 2 · answered Aug 09 '16 at 13:12

This maybe help someone if stumbled on this problem.

Opening files in other apps is not working in iOS simulator because it doesn't see any other apps. So you should be testing it on a physical device

Also you need to provide Uti for UIDocumentInteractionController like this:

documentInteractionController.Uti = @"com.adobe.pdf"

Used this xamarin forum topic for example.

score 0 · Answer 3 · answered Nov 03 '22 at 13:27

What works for me in Maui is:

    MainThread.BeginInvokeOnMainThread(() =>
    {
        try
        {
            var documentInteractionController = new UIDocumentInteractionController();

            NSUrl URL = new NSUrl(fullFilename, false);

            documentInteractionController = UIDocumentInteractionController.FromUrl(URL);

            var view = Platform.GetCurrentUIViewController().View;
            documentInteractionController.PresentOpenInMenu(view.Frame, view, true);
        }
        catch (Exception e)
        {
            Console.WriteLine(e);
        }

    });

fullFilename is the filename including full local path to the file you have saved in your app sandbox location.

How to implement UIDocumentInteractionController on iPad using Xamarin

3 Answers3