我正在使用 Android Studio 开发一个健身应用程序,并以 Room 作为数据库。我在 WorkoutDao 中遇到 Room 查询和插入问题。具体来说,我看到与处理游标和延续相关的错误。尽管遵循 Room 文档和一些指南,我似乎无法解决这些问题。
错误信息: 错误:“不确定如何将 Cursor 转换为此方法的返回类型 (java.lang.Object)” 出现在以下查询中:
获取锻炼锻炼 获取锻炼组数 错误:“参数的类型必须是用 @Entity 注释的类或其集合/数组。”
未使用的参数:查询中的$completion。
package com.example.teampotentialfitness
import androidx.room.Dao
import androidx.room.Insert
import androidx.room.OnConflictStrategy
import androidx.room.Query
import kotlinx.coroutines.flow.Flow
@Dao
interface WorkoutDao {
@Insert(onConflict = OnConflictStrategy.REPLACE)
suspend fun insertWorkout(workout: Workout): Long
@Insert(onConflict = OnConflictStrategy.REPLACE)
suspend fun insertExercise(exercise: Exercise): Long
@Insert(onConflict = OnConflictStrategy.REPLACE)
suspend fun insertSet(set: Set): Long
@Query("SELECT * FROM exercise_table WHERE workoutId = :workoutId")
fun getExercisesForWorkout(workoutId: Int): Flow<List<Exercise>>
@Query("SELECT * FROM set_table WHERE exerciseId = :exerciseId")
fun getSetsForExercise(exerciseId: Int): Flow<List<Set>>
}
package com.example.teampotentialfitness
import android.content.Context
import androidx.room.Database
import androidx.room.Room
import androidx.room.RoomDatabase
@Database(entities = [Exercise::class, Workout::class, Set::class], version = 1)
abstract class WorkoutDatabase : RoomDatabase() {
abstract fun workoutDao(): WorkoutDao
companion object {
@Volatile
private var INSTANCE: WorkoutDatabase? = null
fun getDatabase(context: Context): WorkoutDatabase {
return INSTANCE ?: synchronized(this) {
val instance = Room.databaseBuilder(
context.applicationContext,
WorkoutDatabase::class.java,
"workout_database"
).build()
INSTANCE = instance
instance
}
}
}
}
package com.example.teampotentialfitness
import androidx.room.Entity
import androidx.room.PrimaryKey
@Entity(tableName = "exercise_table")
data class Exercise(
@PrimaryKey(autoGenerate = true)
val id: Int = 0,
val name: String,
val workoutId: Int
)
package com.example.teampotentialfitness
import androidx.room.Entity
import androidx.room.PrimaryKey
@Entity(tableName = "workout_table")
data class Workout(
@PrimaryKey(autoGenerate = true)
val id: Int = 0,
val workoutName: String
)
package com.example.teampotentialfitness
import androidx.room.Entity
import androidx.room.PrimaryKey
@Entity(tableName = "set_table")
data class Set(
@PrimaryKey(autoGenerate = true)
val id: Int = 0,
val reps: Int,
val weight: Float,
val exerciseId: Int
)
package com.example.teampotentialfitness
import android.os.Bundle
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import androidx.activity.enableEdgeToEdge
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.foundation.layout.padding
import androidx.compose.material3.ExperimentalMaterial3Api
import androidx.compose.material3.Scaffold
import androidx.compose.material3.Text
import androidx.compose.runtime.Composable
import androidx.compose.ui.Modifier
import androidx.compose.ui.tooling.preview.Preview
import com.example.teampotentialfitness.ui.theme.TeamPotentialFitnessTheme
class MainActivity : ComponentActivity() {
@OptIn(ExperimentalMaterial3Api::class)
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
enableEdgeToEdge()
setContent {
TeamPotentialFitnessTheme {
Scaffold(modifier = Modifier.fillMaxSize()) { innerPadding ->
Greeting(name = "Team Potential Fitness", modifier = Modifier.padding(innerPadding))
}
}
}
}
}
@Composable
fun Greeting(name: String, modifier: Modifier = Modifier) {
Text(text = "Welcome to $name!", modifier = modifier)
}
@Preview(showBackground = true)
@Composable
fun GreetingPreview() {
TeamPotentialFitnessTheme {
Greeting("Team Potential Fitness")
}
}
plugins {
id 'com.android.application'
id 'org.jetbrains.kotlin.android'
id 'kotlin-kapt'
}
android {
compileSdk 34
defaultConfig {
applicationId "com.example.teampotentialfitness"
minSdk 21
targetSdk 34
versionCode 1
versionName "1.0"
javaCompileOptions {
annotationProcessorOptions {
arguments += ["room.schemaLocation": "$projectDir/schemas".toString()]
}
}
}
buildFeatures {
compose true
}
composeOptions {
kotlinCompilerExtensionVersion "1.5.1"
}
kotlinOptions {
jvmTarget = '17'
}
compileOptions {
sourceCompatibility JavaVersion.VERSION_17
targetCompatibility JavaVersion.VERSION_17
}
}
dependencies {
implementation "androidx.compose.ui:ui:1.5.0"
implementation "androidx.compose.material3:material3:1.1.0"
implementation "androidx.lifecycle:lifecycle-runtime-compose:2.6.1"
implementation "androidx.room:room-runtime:2.5.2"
kapt "androidx.room:room-compiler:2.5.2"
implementation "androidx.room:room-ktx:2.5.2"
implementation "org.jetbrains.kotlinx:kotlinx-coroutines-core:1.7.1"
implementation "org.jetbrains.kotlinx:kotlinx-coroutines-android:1.7.1"
implementation "androidx.activity:activity-compose:1.7.2"
testImplementation "junit:junit:4.13.2"
androidTestImplementation "androidx.test.ext:junit:1.1.5"
androidTestImplementation "androidx.test.espresso:espresso-core:3.5.1"
debugImplementation "androidx.compose.ui:ui-tooling:1.5.0"
debugImplementation "androidx.compose.ui:ui-test-manifest:1.5.0"
}
**我尝试了多种解决方案,例如更改方法签名、调整数据库查询和调整构建配置,但问题仍然存在。
有人遇到过类似的问题或者可以提出解决方案来解决这些 Room 数据库问题吗?
提前致谢!**
我一直在使用 Kotlin 和 Android Studio 开发健身应用程序,集成 Room 数据库来管理 Workout、Exercise 和 Set 实体。通过 WorkoutDao 类中的 Kotlin 协程运行 Room 查询或插入操作时会出现此问题。具体来说,在查询数据库或尝试插入数据时,我收到“不确定如何转换游标”和“未使用的参数”错误。
鉴于我遵循 Room 和 Kotlin 协程最佳实践,我希望查询和插入能够顺利进行,但这些错误仍然存在。我试过了:
更正查询和插入中的数据类型。 验证实体是否已正确注释。 确保在 WorkoutDao 中正确使用具有挂起功能的协程。 在数据库构建器中运行fallbackToDestructiveMigration()。 检查 WorkoutDao 返回类型是否导致数据库读取和转换数据的方式出现问题。 尽管进行了这些尝试,错误仍然存在。下面是相关代码供参考。
此错误是由于实体名称
Set
!将实体类名称更改为其他名称,因为 Kotlin 中有一个名为 Set
的内置数据类型,它与您的实体名称冲突。