未找到房间数据库实现 w/Jetpack 撰写

Question

我浏览了这里和其他网站，但我找不到解决方案。

一切正常，直到我在 MainActivity.kt 中初始化 RoomViewModel.kt。

我一直收到这个错误

    java.lang.RuntimeException: cannot find implementation for com.caller.fakecaller.data.DataBase. DataBase_Impl does not exist
        at androidx.room.Room.getGeneratedImplementation(Room.java:97)
        at androidx.room.RoomDatabase$Builder.build(RoomDatabase.java:1358)
        at com.caller.fakecaller.data.DataBase$Companion.getInstance(DataBase.kt:31)
        at com.caller.fakecaller.data.RoomViewModel.<init>(RoomViewModel.kt:18)
        at com.caller.fakecaller.util.RoomViewModelFactory.create(RoomViewModelFactory.kt:14)...

我有这个gradle

plugins {
    id 'com.android.application'
    id 'org.jetbrains.kotlin.android'
}

android {
    compileSdk 31

    defaultConfig {
        applicationId "com.caller.fakecaller"
        minSdk 21
        targetSdk 31
        versionCode 1
        versionName "1.0"

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
        vectorDrawables {
            useSupportLibrary true
        }
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
    kotlinOptions {
        jvmTarget = '1.8'
    }
    buildFeatures {
        compose true
    }
    composeOptions {
        kotlinCompilerExtensionVersion '1.0.2'
    }
    packagingOptions {
        resources {
            excludes += '/META-INF/{AL2.0,LGPL2.1}'
        }
    }
}

dependencies {

    implementation 'androidx.core:core-ktx:1.6.0'
    implementation "androidx.compose.ui:ui:1.0.2"
    implementation "androidx.compose.material:material:1.0.2"
    implementation "androidx.compose.ui:ui-tooling-preview:1.0.2"
    implementation 'androidx.lifecycle:lifecycle-runtime-ktx:2.3.1'
    implementation 'androidx.activity:activity-compose:1.3.1'
    testImplementation 'junit:junit:4.13.2'
    androidTestImplementation 'androidx.test.ext:junit:1.1.3'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
    androidTestImplementation "androidx.compose.ui:ui-test-junit4:1.0.2"
    debugImplementation "androidx.compose.ui:ui-tooling:1.0.2"

    //Room
    implementation "androidx.room:room-runtime:2.3.0"
    annotationProcessor "androidx.room:room-compiler:2.3.0"
    // optional - Kotlin Extensions and Coroutines support for Room
    implementation("androidx.room:room-ktx:2.3.0")

    // Lifecycle components
    implementation "androidx.lifecycle:lifecycle-livedata-ktx:2.3.1"
    implementation "androidx.lifecycle:lifecycle-extensions:2.2.0"
    implementation "androidx.lifecycle:lifecycle-common-java8:2.3.1"
    implementation "androidx.lifecycle:lifecycle-viewmodel-ktx:2.3.1"

    //Navigation with Compose
    implementation("androidx.navigation:navigation-compose:2.4.0-alpha08")

    //Preferences
    implementation("androidx.preference:preference-ktx:1.1.1")

    //Activity
    implementation 'androidx.activity:activity-ktx:1.4.0-alpha01'

    //Glide Accompanist
    implementation "dev.chrisbanes.accompanist:accompanist-glide:0.4.2"

}

当我添加插件 kotlin-android 和 kotlin-kapt 时，它说找不到它们。因此我不得不将应用程序 gradle 更改为这样（基于其他帖子）

// Top-level build file where you can add configuration options common to all sub-projects/modules.
task clean(type: Delete) {
    delete rootProject.buildDir
}
buildscript {

    repositories {
        google()
        mavenCentral()
    }
    dependencies {
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:1.5.30"
    }
}

allprojects {
    configurations.all {
        resolutionStrategy {
            cacheChangingModulesFor 0, 'seconds'
        }
    }
}

但这给了我这些错误

com/android/build/gradle/BaseExtension
> com.android.build.gradle.BaseExtension


Unable to load class 'com.android.build.gradle.BaseExtension'.

在数据库文件中我做了如下操作：

private const val DATABASE_NAME = "FakeCaller"


@Database(entities = [Contact::class, RingTone::class], version = 1, exportSchema = false)
abstract class DataBase:RoomDatabase() {

    abstract fun UserDao(): UserDao

    abstract fun RingDao():RingDao

//Implementing the DataBase
    companion object {
        @Volatile
        private var INSTANCE: DataBase? = null

        fun getInstance(context: Context): DataBase {
            synchronized(this) {
                var instance = INSTANCE

                if (instance == null) {
                    instance = Room.databaseBuilder(
                        context.applicationContext,
                        DataBase::class.java,
                        DATABASE_NAME
                    ).build()

                    INSTANCE = instance
                }
                return instance
            }
        }
    }
}

并将所有内容连接到 RoomViewModel（我也为它创建了一个工厂）

class RoomViewModel(application: Application) : AndroidViewModel(application) {

    val readContactList : LiveData<List<Contact>>
    val readFileUri: LiveData<Uri>
    private val repository : Repository

    init {
        val dbInstance = DataBase.getInstance(application)
        val userDao = dbInstance.UserDao()
        val ringDao = dbInstance.RingDao()
        repository = Repository(userDao, ringDao)
        readContactList = repository.getContacts
        readFileUri = repository.getUri()
    }

    suspend fun getContact(id:Long): LiveData<Contact>{
        return repository.getContact(id)
    }
...
}

在 MainActivity 中我做了这个

setContent {
            FakeCallerTheme {
                // A surface container using the 'background' color from the theme
                Surface(
                    modifier = Modifier.fillMaxSize(),
                    color = MaterialTheme.colors.background
                ) {
                    val context = LocalContext.current
                    val roomViewModel: RoomViewModel = viewModel(
                        factory = RoomViewModelFactory(context.applicationContext as Application)
                    )
                    Greeting("Android")
                }

我认为上下文有问题，但我真的不知道。仍在学习中...

请帮忙

Answer 1

应该有帮助。

现代方法：

在 plugins 块内，

plugins {
    id 'com.android.application'
    id 'kotlin-android'
    id 'kotlin-kapt' //Add this
}

然后，dependencies，

    kapt "androidx.room:room-compiler:$rootProject.roomVersion"

基于下面的评论，

这些都是我构建良好所需要的。


    implementation "androidx.room:room-ktx:$rootProject.roomVersion"
    kapt "androidx.room:room-compiler:$rootProject.roomVersion"
    androidTestImplementation "androidx.room:room-testing:$rootProject.roomVersion"

嘿等等，你连接到互联网了吗？这些可能需要工作室从网上下载（自动下载）。如果下载没有开始，请检查 gradle 是否配置为离线工作。如果是，切换状态，它将下载。

根据下面的评论，这似乎已经解决了问题

project-level-build{
 dependencies{
  classpath 'com.android.tools.build:gradle:7.1.0-alpha04' 
  classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
 }
}

未找到房间数据库实现 w/Jetpack 撰写

Room DataBase Implementation not found w/Jetpack Compose

kotlin

android-room

android-jetpack-compose