Android无法实例化Application：Hilt相关ClassNotFoundException问题求助

错误日志 #

FATAL EXCEPTION: main
Process: com.heet.sleepmagic, PID: 18977
java.lang.RuntimeException: Unable to instantiate application com.heet.sleepmagic.MainApp package com.heet.sleepmagic: java.lang.ClassNotFoundException: Didn't find class "com.heet.sleepmagic.MainApp" on path: DexPathList[[zip file "/data/app/~~vhnGOdaJiLk6ztERW8DzSg==/com.heet.sleepmagic-8TvtgzEu5imBuAIS-WXaGQ==/base.apk"],nativeLibraryDirectories=[/data/app/~~vhnGOdaJiLk6ztERW8DzSg==/com.heet.sleepmagic-8TvtgzEu5imBuAIS-WXaGQ==/lib/x86_64, /system/lib64, /system_ext/lib64]]
at android.app.LoadedApk.makeApplicationInner(LoadedApk.java:1466)
at android.app.LoadedApk.makeApplicationInner(LoadedApk.java:1395)
at android.app.ActivityThread.handleBindApplication(ActivityThread.java:6720)
at android.app.ActivityThread.-$$Nest$mhandleBindApplication(Unknown Source:0)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2133)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loopOnce(Looper.java:201)
at android.os.Looper.loop(Looper.java:288)
at android.app.ActivityThread.main(ActivityThread.java:7872)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:548)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:936)
Caused by: java.lang.ClassNotFoundException: Didn't find class "com.heet.sleepmagic.MainApp" on path: DexPathList[[zip file "/data/app/~~vhnGOdaJiLk6ztERW8DzSg==/com.heet.sleepmagic-8TvtgzEu5imBuAIS-WXaGQ==/base.apk"],nativeLibraryDirectories=[/data/app/~~vhnGOdaJiLk6ztERW8DzSg==/com.heet.sleepmagic-8TvtgzEu5imBuAIS-WXaGQ==/lib/x86_64, /system/lib64, /system_ext/lib64]]
at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:259)
at java.lang.ClassLoader.loadClass(ClassLoader.java:379)
at java.lang.ClassLoader.loadClass(ClassLoader.java:312)
at android.app.AppComponentFactory.instantiateApplication(AppComponentFactory.java:76)
at androidx.core.app.CoreComponentFactory.instantiateApplication(CoreComponentFactory.java:52)
at android.app.Instrumentation.newApplication(Instrumentation.java:1243)
at android.app.LoadedApk.makeApplicationInner(LoadedApk.java:1458)
at android.app.LoadedApk.makeApplicationInner(LoadedApk.java:1395) 
at android.app.ActivityThread.handleBindApplication(ActivityThread.java:6720) 
at android.app.ActivityThread.-$$Nest$mhandleBindApplication(Unknown Source:0) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2133)
at android.os.Handler.dispatchMessage(Handler.java:106) 
at android.os.Looper.loopOnce(Looper.java:201) 
at android.os.Looper.loop(Looper.java:288) 
at android.app.ActivityThread.main(ActivityThread.java:7872) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:548) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:936) 
Suppressed: java.lang.NoClassDefFoundError: Failed resolution of: Lcom/heet/sleepmagic/Hilt_MainApp;
at java.lang.VMClassLoader.findLoadedClass(Native Method)
at java.lang.ClassLoader.findLoadedClass(ClassLoader.java:738)
at java.lang.ClassLoader.loadClass(ClassLoader.java:363)
... 16 more
Caused by: java.lang.ClassNotFoundException: Didn't find class "com.heet.sleepmagic.Hilt_MainApp" on path: DexPathList[[zip file "/data/app/~~vhnGOdaJiLk6ztERW8DzSg==/com.heet.sleepmagic-8TvtgzEu5imBuAIS-WXaGQ==/base.apk"],nativeLibraryDirectories=[/data/app/~~vhnGOdaJiLk6ztERW8DzSg==/com.heet.sleepmagic-8TvtgzEu5imBuAIS-WXaGQ==/lib/x86_64, /system/lib64, /system_ext/lib64]]
at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:259)
at java.lang.ClassLoader.loadClass(ClassLoader.java:379)
at java.lang.ClassLoader.loadClass(ClassLoader.java:312)
... 19 more

项目配置与代码 #

模块级build.gradle #

plugins {
    id("com.android.application")
    id("org.jetbrains.kotlin.android")
    id ("dagger.hilt.android.plugin")
}

android {
    namespace = "com.heet.sleepmagic"
    compileSdk = 34

    defaultConfig {
        applicationId = "com.heet.sleepmagic"
        minSdk = 24
        targetSdk = 34
        versionCode = 1
        versionName = "1.0"

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

    buildTypes {
        release {
            isMinifyEnabled = 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 = "1.4.3"
    }
    packaging {
        resources {
            excludes += "/META-INF/{AL2.0,LGPL2.1}"
        }
    }
}

dependencies {

    implementation("androidx.core:core-ktx:1.9.0")
    implementation("androidx.lifecycle:lifecycle-runtime-ktx:2.6.2")
    implementation("androidx.activity:activity-compose:1.8.0")
    implementation(platform("androidx.compose:compose-bom:2023.03.00"))
    implementation("androidx.compose.ui:ui")
    implementation("androidx.compose.ui:ui-graphics")
    implementation("androidx.compose.ui:ui-tooling-preview")
    implementation("androidx.compose.material3:material3")
    testImplementation("junit:junit:4.13.2")
    androidTestImplementation("androidx.test.ext:junit:1.1.5")
    androidTestImplementation("androidx.test.espresso:espresso-core:3.5.1")
    androidTestImplementation(platform("androidx.compose:compose-bom:2023.03.00"))
    androidTestImplementation("androidx.compose.ui:ui-test-junit4")
    debugImplementation("androidx.compose.ui:ui-tooling")
    debugImplementation("androidx.compose.ui:ui-test-manifest")

    // Compose dependencies
    implementation ("androidx.lifecycle:lifecycle-viewmodel-compose:2.6.2")
    implementation ("androidx.navigation:navigation-compose:2.7.4")

    //Dagger - Hilt
    implementation ("com.google.dagger:hilt-android:2.42")
    annotationProcessor ("com.google.dagger:hilt-android-compiler:2.42")
    annotationProcessor ("androidx.hilt:hilt-compiler:1.0.0")
    implementation ("androidx.hilt:hilt-navigation-compose:1.0.0")

    //Coil
    implementation ("io.coil-kt:coil-compose:2.3.0")
}

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">

    <application
        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:name=".MainApp"
        android:theme="@style/Theme.SleepMagic"
        tools:targetApi="31">
        <activity
            android:name=".MainActivity"
            android:exported="true"
            android:label="@string/app_name"
            android:theme="@style/Theme.SleepMagic">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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

</manifest>

MainApp.kt #

package com.heet.sleepmagic

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

@HiltAndroidApp 
class MainApp:Application()

MainActivity.kt #

package com.heet.sleepmagic

import android.os.Bundle
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.material3.MaterialTheme
import androidx.compose.material3.Surface
import androidx.compose.material3.Text
import androidx.compose.runtime.Composable
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.tooling.preview.Preview
import androidx.compose.ui.unit.sp
import androidx.navigation.compose.rememberNavController
import com.heet.sleepmagic.ui.navigation.Navigation
import com.heet.sleepmagic.ui.theme.HattonFontFamily
import com.heet.sleepmagic.ui.theme.HattonTypography
import com.heet.sleepmagic.ui.theme.SleepMagicTheme
import dagger.hilt.android.AndroidEntryPoint

@AndroidEntryPoint
class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            SleepMagicTheme {
                Navigation(navController = rememberNavController())
            }
        }
    }
}

解决方案 #

核心问题是Hilt生成的Hilt_MainApp类未被正确打包到APK中，导致系统找不到MainApp类，以下是具体修复步骤：

1. 替换annotationProcessor为kapt #

项目使用Kotlin，Hilt注解处理器需用kapt而非Java项目的annotationProcessor：

• 在模块级build.gradle的plugins块添加kapt插件：

plugins {
    id("com.android.application")
    id("org.jetbrains.kotlin.android")
    id("dagger.hilt.android.plugin")
    id("kotlin-kapt") // 新增该行
}

• 将所有annotationProcessor替换为kapt：

//Dagger - Hilt
implementation ("com.google.dagger:hilt-android:2.42")
kapt ("com.google.dagger:hilt-android-compiler:2.42")
kapt ("androidx.hilt:hilt-compiler:1.0.0")
implementation ("androidx.hilt:hilt-navigation-compose:1.0.0")

2. 清理并重建项目 #

• 执行Build > Clean Project
• 执行Build > Rebuild Project
• 点击工具栏Sync Project with Gradle Files确保配置生效

3. 升级Hilt版本（可选但推荐） #

旧版本Hilt可能与新Android Studio存在兼容性问题，可升级到稳定版本：

//Dagger - Hilt
implementation ("com.google.dagger:hilt-android:2.48")
kapt ("com.google.dagger:hilt-android-compiler:2.48")
kapt ("androidx.hilt:hilt-compiler:1.1.0")
implementation ("androidx.hilt:hilt-navigation-compose:1.1.0")

4. 禁用增量编译（临时排查） #

若问题仍存在，可临时禁用Kotlin增量编译：

kotlinOptions {
    jvmTarget = "1.8"
    incremental = false // 新增该行
}

之后重新构建项目。

5. 显式配置Multidex（可选） #

虽然minSdk24默认支持Multidex，但显式配置可避免潜在问题：

• 在defaultConfig块添加：

defaultConfig {
    // ...其他配置
    multiDexEnabled = true
}

• 添加Multidex依赖：

implementation ("androidx.multidex:multidex:2.0.1")

内容的提问来源于stack exchange，提问作者heet kanabar