I’m working on a Dagger Hilt setup in my Android project and encountered an error when using @Binds methods.

The error message is:

error: @Binds methods' parameter type must be assignable to the return type public abstract kotlin.time.TimeSource bindTimeSource(@org.jetbrains.annotations.NotNull ^
Here is my AppModule code:

package com.viswa.befocused.di


@Module
@InstallIn(SingletonComponent::class)
abstract class AppModule {
    companion object {
        @Provides
        fun provideFocusedStatisticsDao(db: FocusedDatabase): FocusedStatisticsDao =
            db.focusedStatisticsDao()

        @Singleton
        @Provides
        fun provideDatabase(
            app: Application,
            callback: FocusedDatabase.Callback,
        ): FocusedDatabase =
            Room.databaseBuilder(app, FocusedDatabase::class.java, "focused_database")
                .addCallback(callback)
                .build()

        @ApplicationScope
        @Singleton
        @Provides
        fun provideApplicationScope(): CoroutineScope = CoroutineScope(SupervisorJob())

        @MainDispatcher
        @Singleton
        @Provides
        fun provideMainDispatcher(): CoroutineDispatcher = Dispatchers.Main

        @Provides
        fun provideTimeSourceAdapter(defaultTimeSource: DefaultTimeSource): TimeSourceAdapter {
            return TimeSourceAdapter(defaultTimeSource)
        }
    }

    @Binds
    @JvmSuppressWildcards
    abstract fun bindTimeSource(timeSourceAdapter: TimeSourceAdapter): TimeSource

    @Binds
    @JvmSuppressWildcards
    abstract fun bindPreferencesManager(preferencesManager: DefaultPreferencesManager): PreferencesManager

    @Binds
    @JvmSuppressWildcards
    abstract fun bindPomodoroTimerStateManager(focusedTimerManager: DefaultFocusedTimerStateManager): FocusedTimerStateManager

    @Binds
    @JvmSuppressWildcards
    abstract fun bindTimerServiceManager(timerServiceManager: DefaultTimerServiceManager): TimerServiceManager

    @Binds
    @JvmSuppressWildcards
    abstract fun bindNotificationHelper(notificationHelper: DefaultNotificationHelper): NotificationHelper
}

@Retention(AnnotationRetention.RUNTIME)
@Qualifier
annotation class ApplicationScope

@Retention(AnnotationRetention.RUNTIME)
@Qualifier
annotation class MainDispatcher

I’m using:

• Kotlin version: 1.9.0
• Dagger Hilt version: 2.51.1

The DefaultTimeSource class does not directly implement kotlin.time.TimeSource,
code :

package com.viswa.befocused.feature.timer

import android.os.SystemClock
import javax.inject.Inject

class DefaultTimeSource @Inject constructor() : TimeSource {
    override val elapsedRealTime: Long
        get() = SystemClock.elapsedRealtime()
}

Code : Focused Database

@Database(
    entities = [PomodoroStatistic::class],
    version = 1,
    exportSchema = true
)
abstract class FocusedDatabase : RoomDatabase() {
    abstract fun focusedStatisticsDao(): FocusedStatisticsDao

    class Callback @Inject constructor(
        private val database: Provider<FocusedDatabase>,
        @ApplicationScope private val applicationScope: CoroutineScope,
    ) : RoomDatabase.Callback() {
        override fun onCreate(db: SupportSQLiteDatabase) {
            super.onCreate(db)
        }
    }
}

Code: FocusedStatisticDao

@Dao
interface FocusedStatisticsDao {

    @Query("SELECT * FROM focused_statistics ORDER BY timestampInMilliseconds")
    fun getAllPomodoroStatistics(): Flow<List<PomodoroStatistic>>

    @Insert(onConflict = OnConflictStrategy.REPLACE)
    suspend fun insertPomodoroStatistics(pomodoroStatistic: PomodoroStatistic)

    @Query("DELETE FROM focused_statistics")
    suspend fun deleteAllPomodoroStatistics()

}

Detailed Error

Executing tasks: [:app:assembleDebug] in project C:UsersagentStudioProjectsBeFocused
 
C:UsersagentStudioProjectsBeFocusedappbuildtmpkapt3stubsdebugcomviswabefocuseddatadbFocusedDatabase.java:12: warning: Schema export directory was not provided to the annotation processor so Room cannot export the schema. You can either provide `room.schemaLocation` annotation processor argument by applying the Room Gradle plugin (id 'androidx.room') OR set exportSchema to false.
public abstract class FocusedDatabase extends androidx.room.RoomDatabase {
                ^
C:UsersagentStudioProjectsBeFocusedappbuildtmpkapt3stubsdebugcomviswabefocuseddiAppModule.java:41: error: @Binds methods' parameter type must be assignable to the return type
    public abstract kotlin.time.TimeSource bindTimeSource(@org.jetbrains.annotations.NotNull
                                           ^
* What went wrong:
Execution failed for task ':app:kaptDebugKotlin'.
> A failure occurred while executing org.jetbrains.kotlin.gradle.internal.KaptWithoutKotlincTask$KaptExecutionWorkAction

Any guidance on how to resolve this type assignment issue with Dagger Hilt would be greatly appreciated.

I have tried adding @JvmSuppressWildcards to the @Binds methods but still face the same issue.

Any guidance on how to resolve this type assignment issue with Dagger Hilt would be greatly appreciated.