我正试着用Kotlin和Room Persistence Library写一个简单的应用程序. 我在Android Persistence codelab中关注了the tutorial.
这是我在Kotlin 的AppDatabase
节课:
@Database(entities = arrayOf(User::class), version = 1)
abstract class AppDatabase : RoomDatabase() {
abstract fun userModel(): UserDao
companion object {
private var INSTANCE: AppDatabase? = null
@JvmStatic fun getInMemoryDatabase(context: Context): AppDatabase {
if (INSTANCE == null) {
INSTANCE = Room.inMemoryDatabaseBuilder(context.applicationContext, AppDatabase::class.java).allowMainThreadQueries().build()
}
return INSTANCE!!
}
@JvmStatic fun destroyInstance() {
INSTANCE = null
}
}
}
但当我试图运行这个应用程序时,它立即崩溃了. 以下是崩溃日志(log):
Caused by: java.lang.RuntimeException: cannot find implementation for com.ttp.kotlin.kotlinsample.room.AppDatabase. AppDatabase_Impl does not exist
at android.arch.persistence.room.Room.getGeneratedImplementation(Room.java:90)
at android.arch.persistence.room.RoomDatabase$Builder.build(RoomDatabase.java:340)
at com.ttp.kotlin.kotlinsample.room.AppDatabase$Companion.getInMemoryDatabase(AppDatabase.kt:19)
at com.ttp.kotlin.kotlinsample.MainKotlinActivity.onCreate(MainKotlinActivity.kt:28)
at android.app.Activity.performCreate(Activity.java:6272)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1108)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2387)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2494)
at android.app.ActivityThread.access$900(ActivityThread.java:157)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1356)
看起来AppDatabase_Impl
类不是自动生成的.我判断了从codelab下载的原始java应用程序,发现有AppDatabase_Impl
个是自动生成的.
Kotlin version: 1.1.2-3
Room version: 1.0.0-alpha1
有谁有这方面的经验吗?
Edit:
用kapt
可以解决我的问题.在我的情况下,我必须用kapt
代替annotationProcessor
.