'Flutter crashes on startup: Didn't find class .MainActivity on path DexPathList

I'm using Flutter with the MultiDex builder enabled for Android and encountered a pretty tricky issue. My app was running without any exceptions but when the video_player package was added it just crashed on startup:

FATAL EXCEPTION: main
Process: com.rsg.anygoal, PID: 5883
java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.rsg.anygoal/com.rsg.anygoal.MainActivity}: java.lang.ClassNotFoundException: Didn't find class "com.rsg.anygoal.MainActivity" on path: DexPathList[[zip file "/data/app/com.rsg.anygoal-tCKWlQXJD-iwdHtVRl0qqA==/base.apk"],nativeLibraryDirectories=[/data/app/com.rsg.anygoal-tCKWlQXJD-iwdHtVRl0qqA==/lib/x86, /data/app/com.rsg.anygoal-tCKWlQXJD-iwdHtVRl0qqA==/base.apk!/lib/x86, /system/lib, /vendor/lib]]
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2679)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2856)
    at android.app.ActivityThread.-wrap11(Unknown Source:0)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1589)
    at android.os.Handler.dispatchMessage(Handler.java:106)
    at android.os.Looper.loop(Looper.java:164)
    at android.app.ActivityThread.main(ActivityThread.java:6494)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)
 Caused by: java.lang.ClassNotFoundException: Didn't find class "com.rsg.anygoal.MainActivity" on path: DexPathList[[zip file "/data/app/com.rsg.anygoal-tCKWlQXJD-iwdHtVRl0qqA==/base.apk"],nativeLibraryDirectories=[/data/app/com.rsg.anygoal-tCKWlQXJD-iwdHtVRl0qqA==/lib/x86, /data/app/com.rsg.anygoal-tCKWlQXJD-iwdHtVRl0qqA==/base.apk!/lib/x86, /system/lib, /vendor/lib]]
    at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:125)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:379)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:312)
    at android.app.Instrumentation.newActivity(Instrumentation.java:1174)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2669)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2856) 
    at android.app.ActivityThread.-wrap11(Unknown Source:0) 
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1589) 
    at android.os.Handler.dispatchMessage(Handler.java:106) 
    at android.os.Looper.loop(Looper.java:164) 
    at android.app.ActivityThread.main(ActivityThread.java:6494) 
    at java.lang.reflect.Method.invoke(Native Method) 
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)

Later while investigating the issue I tried to disable MultiDex and that seemingly fixed it, but then adding additional flutter package broke the app again, so I decided it's not strictly caused by multiDex and re-enabled it.

Another fix attempt I found in forums was to rename ".MainActivity" to the exact class path "com.*...*.MainActivity" but that did not help either.

Hopefully someone will suggest a possible fix to this! Leaving a few more logs and code snippets I collected during my investigation, which may include clues helpful to you.

Full Android logcat logs: https://pastebin.com/vPs614jj

Flutter pubspec (name and description intentionally omitted):

version: 1.0.6+16
environment:
  sdk: ">=2.1.0 <3.0.0"

dependencies:
  flutter:
    sdk: flutter
  cupertino_icons: ^0.1.2
  intl: ^0.15.8
  firebase_core: ^0.4.3+1
  firebase_admob: ^0.9.0+10
  firebase_analytics: ^5.0.9
  firebase_auth: ^0.15.3
  firebase_crashlytics: ^0.1.2+4
  firebase_performance: ^0.3.1+5
  firebase_remote_config: ^0.3.0+1
  firebase_messaging: ^6.0.9
  firebase_dynamic_links: ^0.5.0+9
  cloud_firestore: ^0.13.0+1
  cloud_functions: ^0.4.1+6
  google_sign_in: ^4.1.1
  provider: ^4.0.1
  data_connection_checker: ^0.3.4
  shared_preferences: ^0.5.6
  flutter_markdown: ^0.3.2
  url_launcher: ^5.4.1
  barcode_scan: ^1.0.0
  qr_flutter: ^3.2.0
  share: ^0.6.3+5
  video_player: ^0.10.11+2

dev_dependencies:
  flutter_test:
    sdk: flutter

flutter:
  fonts:
    - family: Raleway
      fonts:
        - asset: fonts/Raleway-Regular.ttf
  uses-material-design: true

Android Manifest:

<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="$APP_DOMAIN">
    <application android:name="io.flutter.app.FlutterApplication" android:label="$APP_NAME" android:icon="@mipmap/ic_launcher">
        <activity android:name=".MainActivity" android:launchMode="singleTop" android:theme="@style/LaunchTheme" android:configChanges="orientation|keyboardHidden|keyboard|screenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode" android:hardwareAccelerated="true" android:windowSoftInputMode="adjustResize">
            <meta-data android:name="io.flutter.app.android.SplashScreenUntilFirstFrame" android:value="true" />
            <intent-filter>
                <action android:name="android.intent.action.MAIN"/>
                <category android:name="android.intent.category.LAUNCHER"/>
            </intent-filter>
            <intent-filter>
                <action android:name="FLUTTER_NOTIFICATION_CLICK" />
                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
        </activity>
        <meta-data android:name="com.google.android.gms.ads.APPLICATION_ID" android:value="$APP_ADS_ID"/>
        <meta-data
            android:name="com.google.firebase.messaging.default_notification_icon"
            android:resource="@drawable/notification_icon" />
    </application>

    <uses-permission android:name="android.permission.INTERNET"/>
</manifest>

MainActivity.java:

import android.os.Bundle;
import io.flutter.app.FlutterActivity;
import io.flutter.plugins.GeneratedPluginRegistrant;

public class MainActivity extends FlutterActivity {
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    GeneratedPluginRegistrant.registerWith(this);
  }
}

Flutter doctor output (XCode shouldn't matter):

Doctor summary (to see all details, run flutter doctor -v):
[✓] Flutter (Channel stable, v1.17.5, on Mac OS X 10.15.4 19E287, locale en-BG)
 
[✓] Android toolchain - develop for Android devices (Android SDK version 29.0.3)
[!] Xcode - develop for iOS and macOS
    ✗ Xcode installation is incomplete; a full installation is necessary for iOS development.
      Download at: https://developer.apple.com/xcode/download/
      Or install Xcode via the App Store.
      Once installed, run:
        sudo xcode-select --switch /Applications/Xcode.app/Contents/Developer
        sudo xcodebuild -runFirstLaunch
[✓] Android Studio (version 3.5)
[✓] VS Code (version 1.46.1)
[✓] Connected device (1 available)

Solution 1:^[1]

I had similar error, after a "package name" change. My solution was: Update package name also in MainActivity.kt.

In short, all package names should be fixed accordingly.

after that, it is fixed.

Solution 2:^[2]

This happened to me when I [partially] renamed the package name (app ID) from com.example.myappone to com.myapp.one. I thought it'd be sufficient to change just the values in android/app/src/mainAndroidManifest.xml and ios/Runner.xcodeproj/project.pbxproj.

Turns out the actual package names also need to be changed so that the source files are located by the compiler

Solution 3:^[3]

The simplest way to solve this if using Android Studio/Flutter is to:

1:Stop the app,then Open MainActivity.kt:

path : "**android/src/main/kotlin/MainActivity.kt**"

If your package name in MainActivity does not match your app,update it in your MainActivity.kt.

2:Then go to Edit>Find > Replace in Files and replace the previous package name with the new one across the entire app and all files.Restart Android Studio before proceeding to the next step.(Invalidate Caches and Restart)

3:After the restart...Open app/src/build.gradle and enable multidex:

defaultConfig {
    applicationId "com.your.apppackage"
    minSdkVersion 28
    targetSdkVersion 30
    versionCode flutterVersionCode.toInteger()
    versionName flutterVersionName
    multiDexEnabled true //add multidex enabled
}

...and dont forget to add the multidex dependency in the same gradle file:

**dependencies {**
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    implementation 'com.google.android.material:material:1.4.0'
    implementation 'androidx.multidex:multidex:2.0.1' // add it as a dependency here
}

and finally invalidate caches and restart. (File>Invalidate Caches/Restart).

Solution 4:^[4]

In my case, this happened when I accidentally commented out (removed) the line:

package com.mypackagename

from "MainActivity.kt" file while I was editing it! Simply adding it back solved the problem.

Solution 5:^[5]

This is not a beautiful solution but it works. For some reason the dex files doesn't have a MainActivity compiled

So we added to the manifest the FlutterActivity directly and that fixed the problem to us

<application
        android:label="morari"
        android:icon="@mipmap/ic_launcher">
        <activity
            android:name="io.flutter.embedding.android.FlutterActivity"
            ...>
            ...
 </application>

Dex files:

Solution 6:^[6]

Solution: Its simple solution is to go to MainActivity.kt and match the Package-name with AndroidManifest.xml.

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution	Source
Solution 1	ehcp
Solution 2
Solution 3	RileyManda
Solution 4	Shamshun
Solution 5	Tomislav Stankovic
Solution 6	ouflak

'Flutter crashes on startup: Didn't find class .MainActivity on path DexPathList

Solution 1:[1]

Solution 2:[2]

Solution 3:[3]

Solution 4:[4]

Solution 5:[5]

Solution 6:[6]