TypeConverters在@Query中不适用于集合 [英] TypeConverters not working for Collections in @Query

问题描述

我有一个称为事件"的实体，其定义如下:

I've an entity called Events which is defined as follows:

@Entity(tableName = "Events")
data class Event(@PrimaryKey val id: Long, val name: String, val venues: Set<String>, val rating: Int)

我有一对@TypeConverter方法用于处理Set<String>:

I've a pair of @TypeConverter methods for handling Set<String>:

@TypeConverter
fun fromStringToStringSet(str: String): Set<String> = str.split("<|>")

@TypeConverter
fun fromStringSetToString(set: Set<String>): String = set.joinToString("<|>")

在我的Dao中，有一个用@Query注释的方法，如下所示:

In my Dao, I've a method annotated with @Query as follows:

@Query("UPDATE Events SET name = :name, venues = :venues WHERE id = :id")
fun updateAndRetainRating(id: Long, name: String, venues: Set<String>)

当我尝试更新具有2个场所的事件时，出现运行时错误，告诉我无法编译SQL.生成的SQL是:

When I try to update an event with 2 venues, I get a runtime error telling me that the SQL couldn't be compiled. The generated SQL is:

UPDATE Events SET name = ?, venues = ?,? WHERE id = ?

这显然是错误的.查看生成的代码，Room正在获取Set<String>的大小并添加相同数量的? s.

This is obviously wrong. Looking into the generated code, Room is getting the size of Set<String> and adding the same number of ?s.

为什么不使用我的TypeConverter?在其他查询(@Insert和@Query(对于SELECT))中，我没有遇到这个问题.其他TypeConverter也可以正常工作.

Why isn't my TypeConverter being used? I don't face this issue in other queries(@Insert and @Query(for SELECT)). Other TypeConverters are also working fine.

如果我使用List<String> + TypeConverter s代替Set<String>，也会发生相同的问题.

The same issue also occurs if I use List<String> + TypeConverters instead of Set<String>.

推荐答案

此解决方案对我有用: TypeConverter在更新List< Boolean>时不起作用在会议室数据库中

This solution worked for me: TypeConverter not working when updating List<Boolean> in Room Database

基本上，将List<String>替换为ArrayList<String>.

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