dependencies {
// Hilt
implementation "com.google.dagger:hilt-android:2.35.1"
kapt "com.google.dagger:hilt-android-compiler:2.35.1"
// Room
implementation "androidx.room:room-runtime:2.4.0"
kapt "androidx.room:room-compiler:2.4.0"
}
@Database(entities = [MyEntity::class], version = 1, exportSchema = false)
abstract class MyDatabase : RoomDatabase() {
abstract fun myDao(): MyDao
companion object {
@Volatile
private var INSTANCE: MyDatabase? = null
fun getDatabase(context: Context): MyDatabase {
return INSTANCE ?: synchronized(this) {
val instance = Room.databaseBuilder(
context.applicationContext,
MyDatabase::class.java,
"my_database"
).build()
INSTANCE = instance
instance
}
}
}
}
其中 MyDao 是一个 Data Access Object,MyEntity 是一个实体类。
@HiltAndroidApp
class MyApplication : Application() {
}
@Module
@InstallIn(SingletonComponent::class)
object AppModule {
@Singleton
@Provides
fun provideMyDao(database: MyDatabase): MyDao {
return database.myDao()
}
@Singleton
@Provides
fun provideMyDatabase(@ApplicationContext appContext: Context): MyDatabase {
return MyDatabase.getDatabase(appContext)
}
}
注意:@InstallIn 是 Hilt 的注解,用于指定该模块应安装在哪个组件上。在本例中,我们在 SingletonComponent 上安装 AppModule。
@AndroidEntryPoint
class MyActivity : AppCompatActivity() {
@Inject
lateinit var myDao