Passing Java object to and from C#

Yes, the AndroidJavaObject can be a return or a method call. The only downside is that you, as the developer, have to know exactly what the return value is in order to use it properly.

The best way to use it is something like this:

 AndroidJavaObject ajObject;
 //some methods to set the object that you want to call the method on
 AndroidJavaObject returnObj = ajObject.Call<AndroidJavaObject>("method name", "method arguments");

To get a return of a complex object from a static function you do something similar:

 AndroidJavaClass ajClass = new AndroidJavaClass("com.example.package.NameOfClass");
 
 AndroidJavaObject ajObject = ajClass.CallStatic<AndroidJavaObject>("method name", "method arguments");

Basically the lesson here is that you can get any return type you want from a call to an Android method by using the <"return type"> operator.

For passing the AndroidJavaObject as a parameter to a method, you just use it like any other simple type parameter. Just be sure that the type of the AndroidJavaObject that you are sending is what is expected by the Java method, otherwise it will not be called.