How to prevent sharing files from "On My iPhone" folder - xamarin

Question

I have a xamarin forms app that can download files to "on my iphone" folder. But when I download a file on phone, I can go there and I can share it with another app.
But I want to prevent this. When I download a file from my app, I want the file not to be uploaded to another device from "on my iphone".
How to prevent this? Probably I can prevent this with mdm, but how?
Is there a way to prevent it with mdm managed app configuration. Some of my customers said that we can prevent this with the plist file in mdm. But I have very little information about mdm. How to do it with mdm?
I need a solution for ios and android. But especially for ios.
Thank you in advance.

Answer 1

Thank you for reply Jack.
I looked your sending thread and I tried it. But it didn't work for me.
I created MyUINavigationItem that is inherited from UINavigationItem. And I override SetRightBarButtonItem null. After I override UINavigationItem on PdfPreviewController that is inherited from QLPreviewController. And I set NavigationItem as MyUINavigationItem object. But it doesn't work for me. My codes is like these:
public class DocumentView : IDocumentView
{
void IDocumentView.DocumentView(string file, string title)
{
PdfPreviewController previewController = new PdfPreviewController();
if (File.Exists(file))
{
previewController.NavigationItem.SetRightBarButtonItem(null, false); //I tried this line as both comment and not comment but it didn't work
previewController.NavigationItem.SetRightBarButtonItems(null, false); //I tried this line as both comment and not comment but it didn't work
previewController.DataSource = new PDFPreviewControllerDataSource(NSUrl.FromFilename(file), title);
UIApplication.SharedApplication.KeyWindow.RootViewController.PresentViewController(previewController, true, null);
}
}
}
public class PdfPreviewController : QLPreviewController
{
MyUINavigationItem item = new MyUINavigationItem();
public override UINavigationItem NavigationItem => item;
}
public class MyUINavigationItem : UINavigationItem
{
public MyUINavigationItem()
{
}
public override void SetRightBarButtonItem(UIBarButtonItem item, bool animated)
{
//base.SetRightBarButtonItem(item, animated); //I tried this line as comment but it didn't work or
//base.SetRightBarButtonItem(null, animated); //I tried this line but it didn't work
}
public override void SetRightBarButtonItems(UIBarButtonItem[] items, bool animated)
{
//base.SetRightBarButtonItems(items, animated); //I tried this line as comment but it didn't work or
//base.SetRightBarButtonItems(null, animated); //I tried this line but it throwed exception
//base.SetRightBarButtonItems(new UIBarButtonItem[0], animated); //I tried this line but it didn't work
}
}
But after your suggestion I looked for enable or hide share button. And I could access child view controller of UINavigationController and I set RightBarButtonItem enable value false.
public class PdfPreviewController : QLPreviewController
{
public override void ViewDidAppear(bool animated)
{
try
{
ActionMenuControl();
}
catch (Exception ex)
{
}
}
public override void ViewDidLayoutSubviews()
{
try
{
ActionMenuControl();
}
catch (Exception ex)
{
}
}
public void ActionMenuControl()
{
try
{
if (this.ChildViewControllers.Length != 0)
{
var navigationController = this.ChildViewControllers.First() as UINavigationController;
if (navigationController.View.Subviews.Length != 0)
{
var layoutContainerView = navigationController.View.Subviews.FirstOrDefault(x => x is UINavigationBar) as UINavigationBar;
if (layoutContainerView != null)
{
if (layoutContainerView.Items.Length != 0)
{
var item = layoutContainerView.Items[0];
if (item.RightBarButtonItems.Length != 0)
item.RightBarButtonItem.Enabled = false;
}
}
}
var toolbar = navigationController.Toolbar;
if (toolbar != null)
{
if(toolbar.Items.Length != 0)
{
toolbar.Items[0].Enabled = false;
}
}
}
}
catch (Exception ex)
{
}
}
}
It works for right bar. But if opens mp3 files, share button appear on toolbar (on bottom) And I didn't access it. How can I do it for mp3 files? How to access toolbar? (Actually it doesn't work when opens and not move it. But if I open it and move it, it works (because it enters ViewDidLayoutSubviews events))
Sorry for long reply. But I wanted to tell about what I did. Because maybe I did missed something.