Android Room不接受通用字段类型 [英] Android Room's does not accept generic field type

问题描述

我正在尝试创建一个基类，其id字段具有通用类型，例如

I'm trying to have a base class which id field is of a generic type like

class BaseEntity<T>{
  private T id;
  //get, set;
}
class User extends BaseEntity<String> {
  //blah blah blah
}

我有一个这样的DAO:

and I have a DAO like this:

@Dao
public interface UserDao {

    @Query("SELECT * FROM user WHERE id = :id")
    Flowable<User> getUserById(String id);
}

我得到一个编译错误:

app \ build \ generated \ source \ apt \ irrisimples \ debug \ com \ irrisimples \ data \ source \ local \ UserDao_Impl.java:275:错误:找不到符号 最后的T _tmpId; ^

app\build\generated\source\apt\irrisimples\debug\com\irrisimples\data\source\local\UserDao_Impl.java:275: error: cannot find symbol final T _tmpId; ^

并在UserDao_Impl:275中:

and in UserDao_Impl:275:

最终T _tmpId； _tmpId = _cursor.getString(_cursorIndexOfId);

final T _tmpId; _tmpId = _cursor.getString(_cursorIndexOfId);

因此，这意味着Room无法确定T是什么，而无法替换其中的值.是错误还是我做错了什么?

So this means that Room couldn't figure out what was T and replace the value there. Is it a bug or am I doing something wrong?

P.S:使用Android Studio 3.1 BETA 3和Room 1.0.0(经测试1.1.0-alpha2)

P.S: Using Android Studio 3.1 BETA 3, and Room 1.0.0 (tested 1.1.0-alpha2)

推荐答案

参考 Google问题跟踪器

应在1.1.0-alpha3中修复

It should be fixed in 1.1.0-alpha3

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