我正在kotlin中为我的数据库实现实现Room持久性库.
以下是我的Entity
、Dao
和Database
课程:
Food.kt
@Entity
class Food(@ColumnInfo(name = "food_name") var foodName: String,
@ColumnInfo(name = "food_desc") var foodDesc: String,
@ColumnInfo(name = "protein") var protein: Double,
@ColumnInfo(name = "carbs") var carbs: Double,
@ColumnInfo(name = "fat") var fat: Double)
{
@ColumnInfo(name = "id")
@PrimaryKey(autoGenerate = true)
var id: Long = 0
@ColumnInfo(name = "calories")
var calories: Double = 0.toDouble()
}
PersonalizedFood.kt个
@Entity(primaryKeys = arrayOf("food_id","date"))
class PersonalizedFood(@ColumnInfo(name = "quantity") var quantity: Int,
@ColumnInfo(name = "unit") var unit: String,
@ColumnInfo(name = "date") var date: Date){
@ColumnInfo(name = "food_id")
var foodId:Long = 0
}
FoodDao.kt
@Dao
interface FoodDao {
companion object{
const val ID = "id"
const val NAME = "name"
const val PROTEIN = "protein"
const val DESC = "desc"
const val CARBS = "carbs"
const val FAT = "fat"
const val DATE = "date"
const val FOOD_ID = "food_id"
const val ALL_FOOD_LIST = "food"
const val PERSONALISED_FOOD_LIST = "personalised_food"
}
/**
* Returns food details of a food given by food_id
*/
@Query("SELECT * FROM $ALL_FOOD_LIST WHERE $ID=:food_id")
fun getFoodDetails(food_id:Long):Food
/**
* Inserts food items in all_food_list
*/
@Insert
fun addFoodList(list:ArrayList<Food>)
@Insert(onConflict = REPLACE)
fun saveFood(food:PersonalizedFood)
@Query("SELECT * FROM $PERSONALISED_FOOD_LIST WHERE $FOOD_ID=:foodId and $DATE=:date")
fun getFood(foodId:Int, data:Date):PersonalizedFood
@Query("SELECT * FROM $ALL_FOOD_LIST where $ID in (select $FOOD_ID from $PERSONALISED_FOOD_LIST where $DATE = :date)")
fun getFood(date:Date):ArrayList<Food>
}
Converter.kt
class Converter {
companion object{
@TypeConverter
fun fromTimestamp(value: Long?): Date? {
return if (value == null) null else Date(value)
}
@TypeConverter
fun dateToTimestamp(date: Date): Long {
return date.time
}
}
}
FoodDatabase.kt
@Database(entities = arrayOf(Food::class, PersonalizedFood::class), version = 1)
@TypeConverters(Converter::class)
abstract class FoodDatabase : RoomDatabase(){
abstract fun foodDao():FoodDao
companion object{
private val databaseName = "diet"
var dbInstance:FoodDao? = null
fun getInstance(context:Context):FoodDao?{
if(dbInstance == null)
dbInstance = Room.inMemoryDatabaseBuilder(context, FoodDatabase::class.java).build().foodDao()
return dbInstance;
}
}
}
And when i run following code to create database:
FoodDatabase.getInstance(baseContext)?.getFood(Calendar.getInstance().time)
它给了我以下例外:
原因:java.lang.RuntimeException:找不到的实现
Has anyone implemented room persistence in kotlin?
Edited
This question was marked duplicate of this. Though problem statement is same but solution given does not solve my problem. Solution says i have to add replace annotationProcessor
to kapt "android.arch.persistence.room:compiler:1.0.0-alpha1"
dependency. I made those changes and it resulted in gradle error while project build.
信息:Gradle任务[:app:assembleDebug]警告:警告:
编译错误.有关详细信息,请参阅日志(log) 信息:构建在10秒内失败 信息:2个错误 信息:2个警告 信息:查看控制台中的完整输出
我还附上了我的gradle文件:
apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply plugin: 'kotlin-android-extensions'
apply plugin: 'kotlin-kapt'
android {
compileSdkVersion 25
buildToolsVersion "25.0.2"
defaultConfig {
applicationId "com.chandilsachin.diettracker"
minSdkVersion 16
targetSdkVersion 25
versionCode 1
versionName "1.0"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
exclude group: 'com.android.support', module: 'support-annotations'
})
compile "org.jetbrains.kotlin:kotlin-stdlib-jre7:$kotlin_version"
compile 'com.android.support:appcompat-v7:25.0.1'
compile 'com.android.support.constraint:constraint-layout:1.0.0-alpha8'
compile 'com.android.support:cardview-v7:25.0.1'
compile 'com.android.support:recyclerview-v7:25.0.1'
compile 'com.github.ne1c:rainbowmvp:1.2.1'
compile "org.jetbrains.anko:anko-commons:0.10.0"
/*annotationProcessor "android.arch.persistence.room:compiler:1.0.0-alpha1"
compile "android.arch.lifecycle:extensions:1.0.0-alpha1"
annotationProcessor "android.arch.lifecycle:compiler:1.0.0-alpha1"*/
compile "android.arch.persistence.room:runtime:1.0.0-alpha1"
annotationProcessor "android.arch.persistence.room:compiler:1.0.0-alpha1"
kapt "android.arch.persistence.room:compiler:1.0.0-alpha1"
testCompile 'junit:junit:4.12'
}
repositories {
mavenCentral()
}
Has anyone come across this issue?