[mono-android] FindViewById returning a ViewGroupInvoker

[Chris Tacke]

In the end it worked if I requested the FindViewById from the Activity itself, not the Layout:

This fails:

var map = m_layout.FindViewById<MapView>(Resource.Id.DriverMap);

This works:

var map = this.FindViewById<MapView>(Resource.Id.DriverMap);

So that answers #1.  But #2 is still apropos.  Why does the first case above fail?  The MapView *is* in that Layout.

-Chris



> -----Original Message-----
> From: monodroid-bounces at lists.ximian.com [mailto:monodroid-
> bounces at lists.ximian.com] On Behalf Of Chris Tacke
> Sent: Wednesday, February 22, 2012 9:50 AM
> To: Discussions related to Mono for Android
> Subject: [mono-android] FindViewById returning a ViewGroupInvoker
> 
> I have an AbsoluteLayout that contains a MapView.  I load this layout
> in my Activity (which is a MapActivity) like this:
> 
> m_layout = LayoutInflater.Inflate(Resource.Layout.DriverLayout, null);
> SetContentView(m_layout);
> 
> And the MapView shows up on the screen and works just fine.
> 
> The MapView is defined in the layout like this:
> 
>     <com.google.android.maps.MapView
>         android:id="@+id/DriverMap"
>         android:layout_width="800px"
>         android:layout_height="400px"
>         android:layout_x="0px"
>         android:layout_y="100px"
>         android:clickable="true"
>         android:apiKey="mykey" />
> 
> Later on in my app, I'd like to get hold of this MapView so I can zoom
> in on it, but I'm having difficulty.
> 
> My first attempt returned null:
> 
>             var m =
> m_layout.FindViewById<MapView>(Resource.Id.DriverMap);
> 
> A more generic version with a cast fails (i.e. code doesn't continue to
> run past this point - assuming the cast failed)
> 
> var m = (MapView)m_layout.FindViewById (Resource.Id.DriverMap);
> 
> So I tried without a cast:
> 
> var m = m_layout.FindViewById (Resource.Id.DriverMap) as
> Android.GoogleMaps.MapView;
> 
> And again I get back a null;
> 
> So I tried this:
> var m = m_layout.FindViewById(Resource.Id.DriverMap);
> 
> And I *do* get back an object - just not a MapView.  I run this:
> 
> var mt = m.GetType().Name;
> 
> And I get back "ViewGroupInvoker"
> 
> My GoogleFu fails to even find what this type is.  Obviously it's
> related to a ViewGroup, but I've not explicitly created one (maybe the
> MapView does?).  So I guess I have a couple questions:
> 
> 1. How do I get access to my MapView?  I mean that's really what I
> want.
> 2. Why am I getting back this "ViewGroupInvoker" and what is it?
> Getting the right answer (#1) is good, but understanding the failure is
> also important so I don't fall into this again.
> 
> -Chris
> 
> 
> _______________________________________________
> Monodroid mailing list
> Monodroid at lists.ximian.com
> 
> UNSUBSCRIBE INFORMATION:
> http://lists.ximian.com/mailman/listinfo/monodroid