Bizzare behavior of NotifyDataSetChanged() Xamarin.Android - xamarin

Question

I am working on an application that asks the user to provide photos for items.
My main object is following
public class PickedObject
{
int ID { get; set; }
int Name{ get; set; }
bool HasPhotos { get; set; }
}
And I have another table for Photos since one item can have multiple photos.
What's happening is that in my adapter, I have created a recycler view so that if an Item has images, there should be an ImageButton visible in front of it.
Here is my row template
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="wrap_content">
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:weightSum="8">
<TextView
android:id="#+id/lblItemName"
android:layout_width="0dp"
android:layout_weight="6"
android:layout_marginTop="5dp"
android:layout_marginLeft="10dp"
android:layout_height="wrap_content"
android:textSize="20dp"
android:text="" />
<ImageButton
android:layout_weight="1"
android:layout_width="35dp"
android:layout_height="35dp"
android:adjustViewBounds="true"
android:scaleType="fitCenter"
android:layout_marginTop="5dp"
android:background="#android:color/transparent"
android:padding="5dp"
android:src="#drawable/rowcamera"
android:id="#+id/btnCamera" />
<ImageButton
android:layout_weight="1"
android:layout_width="35dp"
android:layout_height="35dp"
android:adjustViewBounds="true"
android:scaleType="fitCenter"
android:layout_marginTop="5dp"
android:background="#android:color/transparent"
android:padding="5dp"
android:src="#drawable/rowpicture"
android:id="#+id/btnPicture" />
</LinearLayout>
In my adapter I am using the following in GetView(int position, View convertView, ViewGroup parent)
public override View GetView(int position, View convertView, ViewGroup parent)
{
ItemViewHolder holder = null;
PickedObject item = _items[position];
View view = convertView;
try
{
if (view != null)
holder = (ItemViewHolder)view.Tag; //Holder
if(holder == null)
{
holder = new ItemViewHolder();
view = _context.LayoutInflater.Inflate(Resource.Layout.ItemRow, null);
holder.ItemName = view.FindViewById<TextView>(Resource.Id.lblItemName);
holder.CameraButton = view.FindViewById<ImageButton>(Resource.Id.btnCamera);
holder.CameraButton.Tag = item.ID;
holder.PictureButton = view.FindViewById<ImageButton>(Resource.Id.btnPicture);
holder.PictureButton.Tag = item.ID;
CameraClickListener cameraListener = new CameraClickListener(_context, this);
cameraListener.CameraClickEvent += CameraClickedEvent;
holder.CameraButton.SetOnClickListener(cameraListener);
ImageClickListener imageClickListener = new ImageClickListener(_context);
imageClickListener.ImageClickEvent += ImageClickedEvent;
holder.PictureButton.SetOnClickListener(imageClickListener);
view.Tag = holder;
}
holder.ItemName.Text = item.Name;
holder.CameraButton.Visibility = ViewStates.Visible;
if (item.HasPhotos)
{
holder.PictureButton.Visibility = ViewStates.Invisible;
}
else
{
holder.PictureButton.Visibility = ViewStates.Visible;
}
}
catch(Exception ex)
{
Log.Error("Item adapter", ex.Message);
}
return view;
}
Now in my MainActivity I have called two activities (for result), One is the camera activity that starts the camera and saves the photo.
The other activity is a gallery type activity that is created within the project.
The activity on result is called as follows:
protected override void OnActivityResult(int requestCode, Result resultCode, Intent data)
{
base.OnActivityResult(requestCode, resultCode, data);
int itemId = CameraApp.ID; // Camera App is a static object to hold data
if (requestCode == General.CAMERA_ACTIVITY) // Camera activity code 110
{
CompleteCameraActivity(resultCode, data); // Save picture into gallery and update db
}
if(requestCode == General.GALLERY_ACTIVITY) // Gallery activity code 113
{
CompleteGalleryActivity(resultCode, data);
}
SectionFragment frag = (SectionFragment)sectionsAdapter.GetItem(viewPager.CurrentItem);
int sectionId = frag.Section.ID;
frag.Adapter.SetPicture(questionId, dataAccess.HasPictures(itemId));
}
The SetPicture method in the adapter is as follows:
public void SetPicture(int id, bool hasPics)
{
Item itm = _items.SingleOrDefault(a => a.ID == id);
if (itm != null)
_items.SingleOrDefault(a => a.ID == id).HasPhotos = hasPics;
this.NotifyDataSetChanged();
}
The application works fine when it comes from Camera activity. It updates the record and also the image button is visible as well.
The trouble comes when the MainActivity gains control after GalleryActivity. When I delete all the images in the gallery the SetPicture method is executed which makes the HasPhotos property to false. But the NotifyDataSetChanged part of the adapter doesn't work (when I test it in debugger the GetView method is not fired for the adapter).
So what happens is that my ListView remains in a state where even if the item has no photos the ImageButton (for pictures) is still available.
Can someone please let me know what I am doing wrong?
EDIT
I noticed that if I scroll the list once and return back to the item, the ImageButton is invisible, that means that it is working but why doesn't it work in StartActivityForResult?