I'm trying to use Android Room 2.3.0 and I'm currently getting the compile errors below:

ProjectDao:

error: Not sure how to handle query method's return type (java.lang.Object). DELETE query methods must either return void or int (the number of deleted rows).
    public abstract java.lang.Object deleteAllProjects(@org.jetbrains.annotations.NotNull()
error: Query method parameters should either be a type that can be converted into a database column or a List / Array that contains such type. You can consider adding a Type Adapter for this.
    kotlin.coroutines.Continuation<? super kotlin.Unit> continuation);
error: Unused parameter: continuation
    public abstract java.lang.Object deleteAllProjects(@org.jetbrains.annotations.NotNull()
error: Type of the parameter must be a class annotated with @Entity or a collection/array of it.
    kotlin.coroutines.Continuation<? super java.lang.Long> continuation);
error: Not sure how to handle insert method's return type.
    public abstract java.lang.Object insertProject(@org.jetbrains.annotations.NotNull()
error: Not sure how to handle delete method's return type. Currently the supported return types are void, int or Int.
    public abstract java.lang.Object deleteProject(@org.jetbrains.annotations.NotNull()
error: Type of the parameter must be a class annotated with @Entity or a collection/array of it.
    kotlin.coroutines.Continuation<? super kotlin.Unit> continuation);

CounterDao:

Execution failed for task ':app:kaptDebugKotlin'.
> A failure occurred while executing org.jetbrains.kotlin.gradle.internal.KaptWithoutKotlincTask$KaptExecutionWorkAction
   > java.lang.reflect.InvocationTargetException (no error message)

However, my ProjectDao.kt file has the following:

@Dao
interface ProjectDao {
    @Query("SELECT * FROM table_projects")
    fun getAll(): List<Project>

    @Insert
    suspend fun insertProject(project: Project): Long

    @Insert
    fun insertProjects(projects: List<Project>)

    @Delete
    suspend fun deleteProject(project: Project)

    @Query("DELETE FROM table_projects")
    suspend fun deleteAllProjects()

    @Transaction
    @Query("SELECT * FROM table_projects")
    fun getAllProjectsWithCounters(): List<ProjectWithCounters>

    @Transaction
    @Query("SELECT * FROM table_projects WHERE id_project=:projectID")
    fun getProjectWithCounters(projectID: Long): ProjectWithCounters
}

I've not had any issue with this previously, and all of a sudden I'm getting these errors and I've no idea what could be causing them.

Thanks!

CodePudding user response：

With the @Delete annotation, you have to define a return data-type:

DELETE query methods must either return void or int (the number of deleted rows).

So this should rather be:

@Delete
suspend fun deleteProject(project: Project): Integer

This would return 1 on success and 0 when the project didn't exist in database.

CodePudding user response：

Set kotlin version is 1.5.21 or 1.5.31
Kotlin 1.6.0 cannot use suspend in ROOM @QUERY
Choose one of the following solutions

1. open your root build.gradle and add this
   classpath 'org.jetbrains.kotlin:kotlin-gradle-plugin:1.5.21'
2. open your module build.gradle and change room-version one of 2.4.0-alpha03 until 2.4.0-beta01
   def roomVersion = "2.4.0-alpha03"