Dropbox Xamarin OAuth Flow Question - Retrieving the Access Token

Thanks - yes, I was able to resolve the ClassNotFound issue. As it happens, I'm pursuing the Java SDK approach after all; it makes more sense and is easier to use for Android than the .NET SDK. I'm still determined to solve this!

I'm still stuck at the redirect point in the auth flow, however. It just tries to redirect in the browser - I can even see the parameters in the address field.

When I reach the redirect point, I'm still not getting back to my app. The redirect URL parameter remains as https://localhost/

I've still got it set in the developer app settings page as well:

My manifest is much the same still:

<activity android:name=".ImageGallery" >      
      <intent-filter>
        <data android:scheme="db-<appkeygoeshere>" />
        <action android:name="android.intent.action.VIEW" />
        <category android:name="android.intent.category.BROWSABLE" />
        <category android:name="android.intent.category.DEFAULT" />
      </intent-filter>
      <intent-filter>
        <data android:scheme="https" android:host="localhost"></data>
        <action android:name="android.intent.action.VIEW"></action>
        <category android:name="android.intent.category.DEFAULT"></category>
        <category android:name="android.intent.category.BROWSABLE"></category>
      </intent-filter>
</activity>

It's got to be something trivial I think, like a typo in my actual auth address or manifest. Right now the auth address looks like this(sensitive values removed):

"https://www.dropbox.com/1/oauth2/authorize?client_id=db-mydropboxappkey& response_type=token&redirect_uri=https://localhost/& state=mygeneratedstateid"

A couple more questions that might help:

In my dropbox developer apps page, this app still has the development status - I don't have to be in production status for this to work right?

Also, I've implemented parts of the Auth and AuthActivity classes from the Java SDK to help me sort this out. One thing I've noticed is when I run AuthActivity.checkAppBeforeAuth, I never get any Activity results when it calls packageManager.QueryIntentActivities. Would that indicate I still don't have the manifest set correctly? 

Edit: I'm still getting the class not found error after all. 

It shows up after I exit debug mode, so without being patient I had thought it was gone. 

One thing I noticed: If I generate an Intent address for ImageGallery, the expanded path to the activity is MyApp.App/md5fac3f4919a5b0b9804623e8f923fe925.ImageGallery. If I use that instead of just .ImageGallery in the <activity> element of my manifest, there's a compilation error. Perhaps that's my issue? I can buid when I append that to my <manifest> element however, so I'll try that next.