Kotlin+Dagger 2“LateInit属性databaseService尚未初始化”

Question

我的代码成功构建，但每当我运行它时都会出现异常。不知道为什么匕首2不初始化变量。请告诉我哪里错了。给出以下例外情况：

UninitializedPropertyAccessException：lateinit属性databaseService尚未初始化

class MyApplication : Application() {

    private val TAG: String = "MyApplication"

    lateinit var applicationComponent: ApplicationComponent

    @Inject
    lateinit var databaseService: DatabaseService

    private lateinit var addedPackages: ArrayList<String>

    override fun onCreate() {
        super.onCreate()
        applicationComponent = buildApplicationComponent()
        applicationComponent.inject(this)

        addedPackages = databaseService.packagesDao().getAllPackages()

    }

    private fun buildApplicationComponent() =
        DaggerApplicationComponent.builder()
            .applicationModule(ApplicationModule(this))
            .build()
}

@Singleton
@Component(modules = [ApplicationModule::class])
interface ApplicationComponent {

    fun inject(application: Application)

    fun databaseService(): DatabaseService

    fun compositeDisposable(): CompositeDisposable

}

@Module
class ApplicationModule(private val application: Application) {

    @ApplicationContext
    @Provides
    fun provideContext() = application

    @Singleton
    @Provides
    fun provideDatabaseService() = Room.databaseBuilder(application, DatabaseService::class.java, "VersionChecker").build()

    @Provides
    fun provideCompositeDisposable() = CompositeDisposable()


}

依赖关系：

dependencies {
    implementation fileTree(dir: "libs", include: ["*.jar"])
    implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
    implementation 'androidx.core:core-ktx:1.3.2'
    implementation 'androidx.appcompat:appcompat:1.2.0'
    implementation 'androidx.constraintlayout:constraintlayout:2.0.2'
    implementation 'androidx.recyclerview:recyclerview:1.1.0'
    implementation 'com.google.android.material:material:1.2.1'
    implementation 'androidx.lifecycle:lifecycle-extensions:2.2.0'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'androidx.test.ext:junit:1.1.2'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.3.0'

    //Room
    implementation 'androidx.room:room-runtime:2.2.5'
    annotationProcessor 'androidx.room:room-compiler:2.2.5'

    //rxjava
    implementation 'io.reactivex.rxjava3:rxandroid:3.0.0'
    implementation 'io.reactivex.rxjava3:rxjava:3.0.0'

    //Dagger2
    implementation 'com.google.dagger:dagger:2.21'
    kapt 'com.google.dagger:dagger-compiler:2.21'

}

Answer 1

在onCreate中初始化databaseService或使用lazy而不是LateInit。