why MenuItemCompat.getActionProvider returns null?

Question

I tried to use android.support.v7.widget.ShareActionProvider on actionbar in my app. So I followed the example from android document but got some issues.
Here\'s my m

Answer 1

the variable: Android.Support.V7.Widget.ShareActionProvider shareActionProvider;

this.MenuInflater.Inflate(Resource.Menu.share_action_provider, menu);
var shareItem = menu.FindItem(Resource.Id.menu_item_share_action_provider_action_bar);
MenuItemCompat.SetShowAsAction (shareItem,  MenuItemCompat.ShowAsActionIfRoom);
var actionprov = new Android.Support.V7.Widget.ShareActionProvider (this);
MenuItemCompat.SetActionProvider (shareItem, actionprov);
var test =  MenuItemCompat.GetActionProvider (shareItem);
shareActionProvider = test.JavaCast();
var intent = new Intent(Intent.ActionSend);
intent.SetType("text/plain");
intent.PutExtra(Intent.ExtraText, "ActionBarCompat is Awesome! Support Lib v7 #Xamarin");
shareActionProvider.SetShareIntent (intent);
return base.OnCreateOptionsMenu(menu); 

this did the trick with me... i just created my own shareactionprovider ! and i set it myself, then get it... and maybe theres some code even thats not needed.. but its a lot of casting AND MAKE SURE you use the right ones all the time, if you just type "ShareActionProvider" you are in fact using V4..! instead of V7