安卓工作室 : Room: error: Cannot find getter for field

Question

我正在使用房间数据库进行本地缓存。在我的实体内部，我还有其他对象，它们的 getter 具有与其用途相关的接口(interface)返回类型。然而，房间无法为这些领域找到 setter/getter 。我的目标是将这些接口(interface)用作返回类型，以便我可以将来自多个远程源的数据添加到一个数组中。我怎样才能做到这一点，同时实现灵活和良好的抽象？

public interface Venue {
  Location getLocation();
  Contact getContact();
}

public interface Location {
  double getLongitude();
  double getLatitude();
}

public interface Contact {
  String getPhoneNumber();
  String getFacebookUsername();
}

public class VenueSourceOne implements Venue{
   private VenueSourceOneLocation venueSourceOneLocation;
   private VenueSourceOneContact venueSourceOneContact;

   Location getLocation(){
      return venueSourceOneLocation;
   }

   Contact getContact(){
      return venueSourceOneContact
   }
}

public class VenueSourceTwo implements Venue{
   private VenueSourceTwoLocation venueSourceTwoLocation;
   private VenueSourceTwoContact venueSourceTwoContact;

   Location getLocation(){
      return venueSourceTwoLocation;
   }

   Contact getContact(){
      return venueSourceTwoContact
   }
}


public class Main{
   ....add to a List<Venue> and do something on the UI
}

Answer 1

由于我提出的问题以外的原因，我将 field 接口(interface)更改为抽象类:

来自

public interface Venue {
  Location getLocation();
  Contact getContact();
}

到

public abstract class Venue {
      public abstract Location getLocation();
      public abstract Contact getContact();
}

我的问题的真正解决方案如下:

来自

public class VenueSourceOne implements Venue{
   private VenueSourceOneLocation venueSourceOneLocation;
   private VenueSourceOneContact venueSourceOneContact;

   Location getLocation(){
      return venueSourceOneLocation;
   }

   Contact getContact(){
      return venueSourceOneContact
   }
}

public class VenueSourceTwo implements Venue{
   private VenueSourceTwoLocation venueSourceTwoLocation;
   private VenueSourceTwoContact venueSourceTwoContact;

   Location getLocation(){
      return venueSourceTwoLocation;
   }

   Contact getContact(){
      return venueSourceTwoContact
   }
}

到

public class VenueSourceOne extends Venue{
   private VenueSourceOneLocation location;
   private VenueSourceOneContact contact;

   @Override
   VenueSourceOneLocation getLocation(){
      return location;
   }

   @Override
   VenueSourceOneContact getContact(){
      return contact;
   }
}

public class VenueSourceTwo extends Venue{
   private VenueSourceTwoLocation location;
   private VenueSourceTwoContact contact;

   @Override
   VenueSourceTwoLocation getLocation(){
      return location;
   }

   @Override
   VenueSourceTwoContact getContact(){
      return contact;
   }
}

当从源中检索数据时，列表将使用抽象类指定的通用类型，而房间将使用特定类型存储数据。