Android ViewModel 没有零参数构造函数，Kotlin Jetpack Compose

Question

我正在尝试制作一个带有API调用的应用程序，但是当我启动时，它因错误而崩溃，在互联网上进行了搜索，但找不到问题所在。 这里有一个错误：

*引起：java.lang.InstantiationException：java.lang.Class没有零参数构造函数*

我的项目结构：

我的代码：

DishApplication.kt：

package com.lobo

import android.app.Application
import dagger.hilt.android.HiltAndroidApp

@HiltAndroidApp
class DishApplication:Application() {
}

api.models：

class DishList : ArrayList<DishListItem>()

data class DishListItem(
    val activeCount: Int,
    val actualPrice: Int,
    val description: String,
    val dishId: Int,
    val isLobobox: Int,
    val name: String,
    val orders: List<Order>,
    val originalPrice: Int,
    val photo: String,
    val tags: List<String>
)

data class Order(
    val actualPrice: Int,
    val customerId: String,
    val orderId: Int,
    val originalPrice: Int,
    val status: String
)

api.requests.GetDishList：

import com.lobo.lobo.data.api.APIConstants
import retrofit2.http.GET
import com.lobo.lobo.data.api.models.DishList
import retrofit2.http.Header

interface GetDishList {

    @GET(APIConstants.DISH_LIST)
    suspend fun getDishes(@Header("Authorization") authHeader: String): DishList

}

API常量：

object APIConstants {
    const val BASE_URL = "my_server_link"
    const val DISH_LIST = "list_dishes"
}

数据.repository.DishRepo：

class DishRepo @Inject constructor(
    private val dishList : GetDishList
){
    suspend fun getDishList(authHeader: String) : DishList{
        return dishList.getDishes(authHeader)
    }
}

lobo.di.DishAPIModule：

@Module
@InstallIn(SingletonComponent::class)
object DishAPIModule {

    @Provides
    @Singleton
    fun provideGetDishList(retrofit: Retrofit): GetDishList {
        return retrofit.create(GetDishList::class.java)
    }

    @Provides
    @Singleton
    fun provideRetrofit(): Retrofit {
        return Retrofit.Builder()
            .baseUrl(APIConstants.BASE_URL)
            .build()
    }

}

lobo.ViewModels.DishesViewModel：

@HiltViewModel
class DishesViewModel @Inject constructor(
    private val dishRepo: DishRepo
) : ViewModel() {

    private val _dishes = MutableLiveData<DishList>()
    val dishes: LiveData<DishList> = _dishes

    fun getDishes(authHeader: String) {
        viewModelScope.launch {
            val dishList = dishRepo.getDishList(authHeader)
            _dishes.postValue(dishList)
        }
    }
}

Dishes.kt（片段）：

@Composable
fun ListOfDishesScreen(navController: NavController) {
    var showDialog by rememberSaveable { mutableStateOf(false) }
    var checkedState by remember { mutableStateOf(false) }

    val viewModel: DishesViewModel = viewModel()

    LaunchedEffect(Unit) {
        viewModel.getDishes("Bearer my_token")
        Log.d("WTF", "token send")
    }

    val dishes by viewModel.dishes.observeAsState()
//some code here
                dishes?.forEach { dish ->
                    DishAPICard(
                        dishName = dish.name,
                        dishPhoto = dish.photo ,  // You will need to load the image from the URL.
                        actualPrice = dish.actualPrice,
                        navController = navController
                    )
                    Spacer(modifier = Modifier.height(16.dp))
                }

MainActivity.kt：

import dagger.hilt.android.AndroidEntryPoint

@AndroidEntryPoint
class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        WindowCompat.setDecorFitsSystemWindows(window, false)
        super.onCreate(savedInstanceState)
        setContent {
            val is_auth = false
            val navController = rememberNavController()

            NavHost(navController, startDestination = if (is_auth) "lol" else "dish_list") {
                composable("dish_list"){ ListOfDishesScreen(navController = navController)}

还添加我的构建gradle文件（mb有一个依赖错误，我尝试了一切）

build.gradle（项目）：

buildscript {
    ext {
        compose_ui_version = '1.2.0'
        hilt_version = '2.43'
    }
}// Top-level build file where you can add configuration options common to all sub-projects/modules.
plugins {
    id 'com.android.application' version '7.4.1' apply false
    id 'com.android.library' version '7.4.1' apply false
    id 'org.jetbrains.kotlin.android' version '1.7.0' apply false
    id 'com.google.dagger.hilt.android' version '2.43' apply false
}

build.gradle（模块：应用程序）：

plugins {
    id 'com.android.application'
    id 'org.jetbrains.kotlin.android'
    id 'kotlin-kapt'
    id 'dagger.hilt.android.plugin'
}
apply plugin: 'kotlin-kapt'



android {
    namespace 'com.lobo.lobo'
    compileSdk 33

    defaultConfig {
        applicationId "com.lobo.lobo"
        minSdk 29
        targetSdk 33
        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 '1.2.0'
    }
    packagingOptions {
        resources {
            excludes += '/META-INF/{AL2.0,LGPL2.1}'
        }
    }
}

dependencies {

    implementation 'androidx.core:core-ktx:1.7.0'
    implementation 'androidx.lifecycle:lifecycle-runtime-ktx:2.3.1'
    implementation 'androidx.activity:activity-compose:1.3.1'
    implementation "androidx.compose.ui:ui:$compose_ui_version"
    implementation "androidx.compose.ui:ui-tooling-preview:$compose_ui_version"
    implementation 'androidx.compose.material:material:1.2.0'
    testImplementation 'junit:junit:4.13.2'
    androidTestImplementation 'androidx.test.ext:junit:1.1.5'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.5.1'
    androidTestImplementation "androidx.compose.ui:ui-test-junit4:$compose_ui_version"
    debugImplementation "androidx.compose.ui:ui-tooling:$compose_ui_version"
    debugImplementation "androidx.compose.ui:ui-test-manifest:$compose_ui_version"
    implementation "androidx.compose.runtime:runtime-livedata:$compose_ui_version"
    implementation 'com.google.accompanist:accompanist-systemuicontroller:0.17.0'
    implementation "com.google.accompanist:accompanist-insets:0.17.0"// Please use the latest version



    // Jetpack Compose Integration
    implementation "androidx.navigation:navigation-compose:2.5.3"

    implementation "com.squareup.retrofit2:retrofit:2.9.0"
    implementation "com.squareup.retrofit2:converter-gson:2.6.0"
    implementation "io.coil-kt:coil-compose:1.3.2"

    implementation 'com.google.dagger:dagger:2.43'
    kapt 'com.google.dagger:hilt-compiler:2.43'
    kapt 'com.google.dagger:dagger-compiler:2.43'
    implementation "com.google.dagger:hilt-android:2.43"
    kapt "com.google.dagger:hilt-android-compiler:2.43"
    kapt "androidx.hilt:hilt-compiler:1.0.0"

    implementation 'androidx.activity:activity-compose:1.3.1'  // Make sure you use the latest version
    implementation 'androidx.activity:activity:1.3.1'  // Make sure you use the latest version
}

我尝试更改依赖项和我的 @Composable 对象，但仍然出现相同的错误

Answer 1

我认为你需要改变

val viewModel: DishesViewModel = viewModel()

到

val viewModel: DishesViewModel = hiltViewModel()

在

Dishes.kt

。