Unable to Access ViewModel from Fragment

[Cengizhanerturan]

I want to access my ViewModel class from a Fragment as shown below:

//Error
private val viewModel: MyViewModel by viewModels()

//No Error
private val viewModel: MyViewModel by activityViewModels()

If no class is injected into my ViewModel class via its constructor, I can access it using this method without encountering any errors. However, when a class is injected into the ViewModel, I am unable to access it, and I encounter the following error:

Error;

2025-01-08 16:37:26.402 12233-12233 AndroidRuntime          com.example.hilttutorial             E  FATAL EXCEPTION: main
                                                                                                    Process: com.example.hilttutorial, PID: 12233
                                                                                                    java.lang.RuntimeException: Cannot create an instance of class com.example.hilttutorial.presentation.my_fragment.MyViewModel
                                                                                                    	at androidx.lifecycle.viewmodel.internal.JvmViewModelProviders.createViewModel(JvmViewModelProviders.kt:40)
                                                                                                    	at androidx.lifecycle.ViewModelProvider$NewInstanceFactory.create(ViewModelProvider.android.kt:193)
                                                                                                    	at androidx.lifecycle.ViewModelProvider$AndroidViewModelFactory.create(ViewModelProvider.android.kt:317)
                                                                                                    	at androidx.lifecycle.ViewModelProvider$AndroidViewModelFactory.create(ViewModelProvider.android.kt:299)
                                                                                                    	at androidx.lifecycle.ViewModelProvider$AndroidViewModelFactory.create(ViewModelProvider.android.kt:273)
                                                                                                    	at androidx.lifecycle.SavedStateViewModelFactory.create(SavedStateViewModelFactory.kt:128)
                                                                                                    	at androidx.lifecycle.ViewModelProvider$Factory.create(ViewModelProvider.android.kt:158)
                                                                                                    	at androidx.lifecycle.viewmodel.ViewModelProviderImpl_androidKt.createViewModel(ViewModelProviderImpl.android.kt:34)
                                                                                                    	at androidx.lifecycle.viewmodel.ViewModelProviderImpl.getViewModel$lifecycle_viewmodel_release(ViewModelProviderImpl.kt:65)
                                                                                                    	at androidx.lifecycle.viewmodel.ViewModelProviderImpl.getViewModel$lifecycle_viewmodel_release$default(ViewModelProviderImpl.kt:47)
                                                                                                    	at androidx.lifecycle.ViewModelProvider.get(ViewModelProvider.android.kt:91)
                                                                                                    	at androidx.lifecycle.ViewModelLazy.getValue(ViewModelLazy.kt:51)
                                                                                                    	at androidx.lifecycle.ViewModelLazy.getValue(ViewModelLazy.kt:35)
                                                                                                    	at com.example.hilttutorial.presentation.my_fragment.MyFragment.getViewModel(MyFragment.kt:15)
                                                                                                    	at com.example.hilttutorial.presentation.my_fragment.MyFragment.onViewCreated(MyFragment.kt:34)
                                                                                                    	at androidx.fragment.app.Fragment.performViewCreated(Fragment.java:3152)
                                                                                                    	at androidx.fragment.app.FragmentStateManager.createView(FragmentStateManager.java:608)
                                                                                                    	at androidx.fragment.app.FragmentStateManager.moveToExpectedState(FragmentStateManager.java:286)
                                                                                                    	at androidx.fragment.app.FragmentStore.moveToExpectedState(FragmentStore.java:114)
                                                                                                    	at androidx.fragment.app.FragmentManager.moveToState(FragmentManager.java:1685)
                                                                                                    	at androidx.fragment.app.FragmentManager.dispatchStateChange(FragmentManager.java:3319)
                                                                                                    	at androidx.fragment.app.FragmentManager.dispatchViewCreated(FragmentManager.java:3230)
                                                                                                    	at androidx.fragment.app.Fragment.performViewCreated(Fragment.java:3153)
                                                                                                    	at androidx.fragment.app.FragmentStateManager.createView(FragmentStateManager.java:608)
                                                                                                    	at androidx.fragment.app.FragmentStateManager.moveToExpectedState(FragmentStateManager.java:286)
                                                                                                    	at androidx.fragment.app.FragmentStore.moveToExpectedState(FragmentStore.java:114)
                                                                                                    	at androidx.fragment.app.FragmentManager.moveToState(FragmentManager.java:1685)
                                                                                                    	at androidx.fragment.app.FragmentManager.dispatchStateChange(FragmentManager.java:3319)
                                                                                                    	at androidx.fragment.app.FragmentManager.dispatchActivityCreated(FragmentManager.java:3237)
                                                                                                    	at androidx.fragment.app.FragmentController.dispatchActivityCreated(FragmentController.java:263)
                                                                                                    	at androidx.fragment.app.FragmentActivity.onStart(FragmentActivity.java:350) at androidx.appcompat.app.AppCompatActivity.onStart(AppCompatActivity.java:251)
                                                                                                    	at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1582)
                                                                                                    	at android.app.Activity.performStart(Activity.java:8628)
                                                                                                    	at android.app.ActivityThread.handleStartActivity(ActivityThread.java:3807)
                                                                                                    	at android.app.servertransaction.TransactionExecutor.performLifecycleSequence(TransactionExecutor.java:225)
                                                                                                    	at android.app.servertransaction.TransactionExecutor.cycleToPath(TransactionExecutor.java:205)
                                                                                                    	at android.app.servertransaction.TransactionExecutor.executeLifecycleState(TransactionExecutor.java:177)
                                                                                                    	at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:98)
                                                                                                    	at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2443)
                                                                                                    	at android.os.Handler.dispatchMessage(Handler.java:106)
                                                                                                    	at android.os.Looper.loopOnce(Looper.java:205)
                                                                                                    	at android.os.Looper.loop(Looper.java:294)
2025-01-08 16:37:26.403 12233-12233 AndroidRuntime          com.example.hilttutorial             E  	at android.app.ActivityThread.main(ActivityThread.java:8177)
                                                                                                    	at java.lang.reflect.Method.invoke(Native Method)
                                                                                                    	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:552)
                                                                                                    	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:971)
                                                                                                    Caused by: java.lang.NoSuchMethodException: com.example.hilttutorial.presentation.my_fragment.MyViewModel.<init> []
                                                                                                    	at java.lang.Class.getConstructor0(Class.java:3325)
                                                                                                    	at java.lang.Class.getDeclaredConstructor(Class.java:3063)
                                                                                                    	at androidx.lifecycle.viewmodel.internal.JvmViewModelProviders.createViewModel(JvmViewModelProviders.kt:38)
                                                                                                    	... 46 more

Note 1

On the other hand, when I try to access the ViewModel using the following method, I don't encounter any issues:

private val viewModel: MyViewModel by activityViewModels()

Note 2

To help better understand the issue, I am attaching the relevant ViewModel, Fragment, and Hilt module files to this report.

AppModule.kt

package com.example.hilttutorial.data.di

import com.example.hilttutorial.data.repository.RepositoryImpl
import com.example.hilttutorial.domain.repository.Repository
import dagger.Module
import dagger.Provides
import dagger.hilt.InstallIn
import dagger.hilt.components.SingletonComponent
import javax.inject.Singleton

@InstallIn(SingletonComponent::class)
@Module
object AppModule {
    @Singleton
    @Provides
    fun provideRepository(): Repository = RepositoryImpl()

}

MyFragment.kt

package com.example.hilttutorial.presentation.my_fragment

import android.os.Bundle
import androidx.fragment.app.Fragment
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import androidx.fragment.app.activityViewModels
import androidx.fragment.app.viewModels
import com.example.hilttutorial.R

class MyFragment : Fragment() {

    // Error
    private val viewModel: MyViewModel by viewModels()

    //No Error
    //private val viewModel: MyViewModel by activityViewModels()

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
    }

    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_my, container, false)
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)

        //ViewModel getData function started
        viewModel.getData()
    }
}

MyViewModel.kt

package com.example.hilttutorial.presentation.my_fragment

import androidx.lifecycle.ViewModel
import com.example.hilttutorial.domain.repository.Repository
import dagger.hilt.android.lifecycle.HiltViewModel
import javax.inject.Inject

@HiltViewModel
class MyViewModel @Inject constructor(
    private val repository: Repository
) : ViewModel() {

    fun getData(): Boolean {
        return repository.getData()
    }
}

Repository.kt

package com.example.hilttutorial.domain.repository

interface Repository {
    fun getData(): Boolean
}

RepositoryImpl.kt

package com.example.hilttutorial.data.repository

import com.example.hilttutorial.domain.repository.Repository

class RepositoryImpl : Repository {
    override fun getData(): Boolean {
        return true
    }
}

MainActivity.kt

package com.example.hilttutorial.presentation

import android.os.Bundle
import androidx.activity.enableEdgeToEdge
import androidx.appcompat.app.AppCompatActivity
import androidx.core.view.ViewCompat
import androidx.core.view.WindowInsetsCompat
import androidx.navigation.fragment.NavHostFragment
import com.example.hilttutorial.R
import com.example.hilttutorial.databinding.ActivityMainBinding
import dagger.hilt.android.AndroidEntryPoint

@AndroidEntryPoint
class MainActivity : AppCompatActivity() {
    private lateinit var binding: ActivityMainBinding
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        enableEdgeToEdge()
        binding = ActivityMainBinding.inflate(layoutInflater)
        val view = binding.root
        setContentView(view)
        ViewCompat.setOnApplyWindowInsetsListener(findViewById(R.id.main)) { v, insets ->
            val systemBars = insets.getInsets(WindowInsetsCompat.Type.systemBars())
            v.setPadding(systemBars.left, systemBars.top, systemBars.right, systemBars.bottom)
            insets
        }
    }
}

HiltTutorialApplication.kt

package com.example.hilttutorial.presentation

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

@HiltAndroidApp
class HiltTutorialApplication : Application() {
}

build.gradle (app)

plugins {
    alias(libs.plugins.android.application)
    alias(libs.plugins.kotlin.android)
    id("androidx.navigation.safeargs.kotlin")
    id("kotlin-kapt")
    id("com.google.dagger.hilt.android")
}

android {
    namespace 'com.example.hilttutorial'
    compileSdk 35

    defaultConfig {
        applicationId "com.example.hilttutorial"
        minSdk 24
        targetSdk 35
        versionCode 1
        versionName "1.0"

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_11
        targetCompatibility JavaVersion.VERSION_11
    }
    kotlinOptions {
        jvmTarget = '11'
    }
    buildFeatures {
        viewBinding = true
        dataBinding = true
    }
}

dependencies {
    implementation libs.androidx.core.ktx
    implementation libs.androidx.appcompat
    implementation libs.material
    implementation libs.androidx.activity
    implementation libs.androidx.constraintlayout
    testImplementation libs.junit
    androidTestImplementation libs.androidx.junit
    androidTestImplementation libs.androidx.espresso.core

    implementation 'androidx.fragment:fragment-ktx:1.8.5'
    implementation 'androidx.activity:activity-ktx:1.9.3'

    // coroutine lifecycle scope
    implementation "androidx.lifecycle:lifecycle-viewmodel-ktx:2.8.7"
    implementation "androidx.lifecycle:lifecycle-runtime-ktx:2.8.7"
    implementation 'androidx.lifecycle:lifecycle-extensions:2.2.0'

    // navigation
    implementation "androidx.navigation:navigation-fragment-ktx:2.8.5"
    implementation "androidx.navigation:navigation-ui-ktx:2.8.5"

    //hilt
    implementation "com.google.dagger:hilt-android:2.54"
    kapt "com.google.dagger:hilt-android-compiler:2.54"
    kapt("org.jetbrains.kotlinx:kotlinx-metadata-jvm:0.5.0")
}

build.gradle (project)

plugins {
    alias(libs.plugins.android.application) apply false
    alias(libs.plugins.kotlin.android) apply false
    id("androidx.navigation.safeargs.kotlin") version "2.8.5" apply false
    id("com.google.dagger.hilt.android") version "2.54" apply false
}

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools">
    
    <uses-permission android:name="android.permission.INTERNET"/>

    <application
        android:name=".presentation.HiltTutorialApplication"
        android:allowBackup="true"
        android:dataExtractionRules="@xml/data_extraction_rules"
        android:fullBackupContent="@xml/backup_rules"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.HiltTutorial"
        tools:targetApi="31">
        <activity
            android:name=".presentation.MainActivity"
            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

[dmapr]

I'm guessing it's the missing @AndroidEntryPoint on the MyFragment class.

[Cengizhanerturan]

I'm guessing it's the missing @AndroidEntryPoint on the MyFragment class.

@dmapr Thank you for your response.

Yes, when I add the @androidentrypoint annotation to my 'MyFragment' class, I do not encounter any errors.

However, is this the correct approach? I have already added the @androidentrypoint annotation to my MainActivity class, and this implies that I need to add @androidentrypoint to each of my fragment classes as well.

[dmapr]

@Cengizhanerturan — yes, it is the correct approach: Inject Dependencies into Android classes.

[Cengizhanerturan]

@Cengizhanerturan — yes, it is the correct approach: Inject Dependencies into Android classes.

@dmapr Got it, thank you for your response.