Why do I get "Manifest merger failed with multiple errors" error when running Flutter Android app?

Question

Context

I have a Flutter Android app that I am trying to run on an emulator in Windows 10.

Problem

When I try to run the app with flutter run I get the following error message:

Manifest merger failed with multiple errors

This is the entire console output:

> flutter run
Using hardware rendering with device Android SDK built for x86. If you notice graphics artifacts, consider enabling
software rendering with "--enable-software-rendering".
Launching lib\main.dart on Android SDK built for x86 in debug mode...
Warning: Mapping new ns http://schemas.android.com/repository/android/common/02 to old ns http://schemas.android.com/repository/android/common/01
Warning: Mapping new ns http://schemas.android.com/repository/android/generic/02 to old ns http://schemas.android.com/repository/android/generic/01
Warning: Mapping new ns http://schemas.android.com/sdk/android/repo/addon2/02 to old ns http://schemas.android.com/sdk/android/repo/addon2/01
Warning: Mapping new ns http://schemas.android.com/sdk/android/repo/repository2/02 to old ns http://schemas.android.com/sdk/android/repo/repository2/01
Warning: Mapping new ns http://schemas.android.com/sdk/android/repo/sys-img2/02 to old ns http://schemas.android.com/sdk/android/repo/sys-img2/01
Warning: Mapping new ns http://schemas.android.com/repository/android/common/02 to old ns http://schemas.android.com/repository/android/common/01
Warning: Mapping new ns http://schemas.android.com/repository/android/generic/02 to old ns http://schemas.android.com/repository/android/generic/01
Warning: Mapping new ns http://schemas.android.com/sdk/android/repo/addon2/02 to old ns http://schemas.android.com/sdk/android/repo/addon2/01
Warning: Mapping new ns http://schemas.android.com/sdk/android/repo/repository2/02 to old ns http://schemas.android.com/sdk/android/repo/repository2/01
Warning: Mapping new ns http://schemas.android.com/sdk/android/repo/sys-img2/02 to old ns http://schemas.android.com/sdk/android/repo/sys-img2/01
Warning: Mapping new ns http://schemas.android.com/repository/android/common/02 to old ns http://schemas.android.com/repository/android/common/01
Warning: Mapping new ns http://schemas.android.com/repository/android/generic/02 to old ns http://schemas.android.com/repository/android/generic/01
Warning: Mapping new ns http://schemas.android.com/sdk/android/repo/addon2/02 to old ns http://schemas.android.com/sdk/android/repo/addon2/01
Warning: Mapping new ns http://schemas.android.com/sdk/android/repo/repository2/02 to old ns http://schemas.android.com/sdk/android/repo/repository2/01
Warning: Mapping new ns http://schemas.android.com/sdk/android/repo/sys-img2/02 to old ns http://schemas.android.com/sdk/android/repo/sys-img2/01
Warning: Mapping new ns http://schemas.android.com/repository/android/common/02 to old ns http://schemas.android.com/repository/android/common/01
Warning: Mapping new ns http://schemas.android.com/repository/android/generic/02 to old ns http://schemas.android.com/repository/android/generic/01
Warning: Mapping new ns http://schemas.android.com/sdk/android/repo/addon2/02 to old ns http://schemas.android.com/sdk/android/repo/addon2/01
Warning: Mapping new ns http://schemas.android.com/sdk/android/repo/repository2/02 to old ns http://schemas.android.com/sdk/android/repo/repository2/01
Warning: Mapping new ns http://schemas.android.com/sdk/android/repo/sys-img2/02 to old ns http://schemas.android.com/sdk/android/repo/sys-img2/01
C:\Users\myteam\Documents\flutter\myapp_mobile\android\app\src\main\AndroidManifest.xml:12:9-42 Error:
        Attribute application@name at AndroidManifest.xml:12:9-42 requires a placeholder substitution but no value for <applicationName> is provided.
C:\Users\myteam\Documents\flutter\myapp_mobile\android\app\src\debug\AndroidManifest.xml Error:
        Validation failed, exiting

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':app:processDebugManifest'.
> Manifest merger failed with multiple errors, see logs

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 6s
Running Gradle task 'assembleDebug'...                              7.4s
Exception: Gradle task assembleDebug failed with exit code 1

Code

AndroidManifest.xml (main)

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.myapp_mobile">
    <!-- io.flutter.app.FlutterApplication is an android.app.Application that
         calls FlutterMain.startInitialization(this); in its onCreate method.
         In most cases you can leave this as-is, but you if you want to provide
         additional functionality it is fine to subclass or reimplement
         FlutterApplication and put your custom class here. -->

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

    <application
        android:name="${applicationName}"
        android:label="My App"
        android:icon="@mipmap/ic_launcher">
        <activity
            android:name=".MainActivity"
            android:launchMode="singleTop"
            android:theme="@style/LaunchTheme"
            android:configChanges="orientation|keyboardHidden|keyboard|screenSize|smallestScreenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"
            android:hardwareAccelerated="true"
            android:windowSoftInputMode="adjustResize">

            <intent-filter>
                <action android:name="android.intent.action.MAIN"/>
                <category android:name="android.intent.category.LAUNCHER"/>
                <action android:name="FLUTTER_NOTIFICATION_CLICK" />
                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>

            <meta-data
            android:name="io.flutter.embedding.android.SplashScreenDrawable"
            android:resource="@drawable/launch_background" />

            <meta-data
            android:name="io.flutter.embedding.android.NormalTheme"
            android:resource="@style/NormalTheme"
            />

        </activity>
        
        <meta-data
            android:name="flutterEmbedding"
            android:value="2" />
    </application>
</manifest>

AndroidManifest.xml (debug)

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.myapp_mobile">
    <!-- Flutter needs it to communicate with the running application
         to allow setting breakpoints, to provide hot reload, etc.
    -->
    <uses-permission android:name="android.permission.INTERNET"/>
    <application android:usesCleartextTraffic="true">
    </application>
</manifest>

build.gradle (android)

buildscript {
    ext.kotlin_version = '1.4.32'
    repositories {
        google()
        jcenter()
    }

    dependencies {
        classpath 'com.android.tools.build:gradle:3.5.0'
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
        classpath 'com.google.gms:google-services:4.3.10'
    }
}

allprojects {
    repositories {
        google()
        jcenter()
    }
}

rootProject.buildDir = '../build'
subprojects {
    project.buildDir = "${rootProject.buildDir}/${project.name}"
}
subprojects {
    project.evaluationDependsOn(':app')
}

task clean(type: Delete) {
    delete rootProject.buildDir
}

build.gradle (android\app)

def localProperties = new Properties()
def localPropertiesFile = rootProject.file('local.properties')
if (localPropertiesFile.exists()) {
    localPropertiesFile.withReader('UTF-8') { reader ->
        localProperties.load(reader)
    }
}

def flutterRoot = localProperties.getProperty('flutter.sdk')
if (flutterRoot == null) {
    throw new GradleException("Flutter SDK not found. Define location with flutter.sdk in the local.properties file.")
}

def flutterVersionCode = localProperties.getProperty('flutter.versionCode')
if (flutterVersionCode == null) {
    flutterVersionCode = '1'
}

def flutterVersionName = localProperties.getProperty('flutter.versionName')
if (flutterVersionName == null) {
    flutterVersionName = '1.0'
}

apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply plugin: 'com.google.gms.google-services'

apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"

def keystoreProperties = new Properties()
def keystorePropertiesFile = rootProject.file('key.properties')
if (keystorePropertiesFile.exists()) {
    keystoreProperties.load(new FileInputStream(keystorePropertiesFile))
}

android {
    compileSdkVersion 28

    sourceSets {
        main.java.srcDirs += 'src/main/kotlin'
    }

    lintOptions {
        disable 'InvalidPackage'
    }

    defaultConfig {
        // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
        applicationId "se.myteam.myapp"
        minSdkVersion 21
        targetSdkVersion 30
        versionCode 3103
        versionName "1.3.0"
        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }

  signingConfigs {
    release {
        keyAlias keystoreProperties['keyAlias']
        keyPassword keystoreProperties['keyPassword']
        storeFile keystoreProperties['storeFile'] ? file(keystoreProperties['storeFile']) : null
        storePassword keystoreProperties['storePassword']
    }
   }

    buildTypes {
        release {
            // TODO: Add your own signing config for the release build.
            // Signing with the debug keys for now, so `flutter run --release` works.
            signingConfig signingConfigs.release
        }
    }
}

flutter {
    source '../..'
}

apply plugin: 'com.android.application'
dependencies {
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'androidx.test:runner:1.1.1'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.1'
    implementation platform('com.google.firebase:firebase-bom:29.0.0')
    implementation 'com.google.firebase:firebase-analytics-ktx'
}

pubspec.yaml

name: myapp
description: A new Flutter project.

# The following defines the version and build number for your application.
# A version number is three numbers separated by dots, like 1.2.43
# followed by an optional build number separated by a +.
# Both the version and the builder number may be overridden in flutter
# build by specifying --build-name and --build-number, respectively.
# Read more about versioning at semver.org.
version: 1.0.0+1

environment:
  sdk: ">=2.12.0 <3.0.0"

dependencies:
  http: ^0.13.4
  flutter:
    sdk: flutter
  firebase_messaging: ^11.0.0
  
  intl: ^0.17.0
  shared_preferences: ^2.0.8
  path_provider_platform_interface: ^2.0.1
  platform: ^3.0.2
  flutter_secure_storage: ^4.2.1
  swipedetector: ^1.2.0
  cupertino_icons: ^1.0.3
  url_launcher: ^6.0.3
  firebase_core: ^1.0.4
  flutter_keyboard_visibility: ^5.1.0
  package_info_plus: ^1.3.0
  firebase_analytics: ^8.3.4

dev_dependencies:
  flutter_test:
    sdk: flutter

# For information on the generic Dart part of this file, see the
# following page: https://www.dartlang.org/tools/pub/pubspec

# The following section is specific to Flutter.
flutter:

  # The following line ensures that the Material Icons font is
  # included with your application, so that you can use the icons in
  # the material Icons class.
  uses-material-design: true
  assets:
    - assets/myapp_logo.png
    - assets/myapp_logo.png
    - assets/logo_small.png
    - assets/green_smiley.png
    - assets/orange_smiley.png
    - assets/red_smiley.png
    - assets/horizontal_line.png


  # To add assets to your application, add an assets section, like this:
  # assets:
  #  - images/a_dot_burr.jpeg
  #  - images/a_dot_ham.jpeg

  # An image asset can refer to one or more resolution-specific "variants", see
  # https://flutter.io/assets-and-images/#resolution-aware.

  # For details regarding adding assets from package dependencies, see
  # https://flutter.io/assets-and-images/#from-packages

  # To add custom fonts to your application, add a fonts section here,
  # in this "flutter" section. Each entry in this list should have a
  # "family" key with the font family name, and a "fonts" key with a
  # list giving the asset and other descriptors for the font. For
  # example:
  # fonts:
  #   - family: Schyler
  #     fonts:
  #       - asset: fonts/Schyler-Regular.ttf
  #       - asset: fonts/Schyler-Italic.ttf
  #         style: italic
  #   - family: Trajan Pro
  #     fonts:
  #       - asset: fonts/TrajanPro.ttf
  #       - asset: fonts/TrajanPro_Bold.ttf
  #         weight: 700
  #
  # For details regarding fonts from package dependencies,
  # see https://flutter.io/custom-fonts/#from-packages

Question and Final Words

Why do I get that error and those warnings? Why can't I run my app? I have already taken a look at some other similar questions but they have not helped so far.

Thanks!

Answer 1

Short answer: In the android mainfest file, remove

android:name="${applicationName}

Run flutter clean and then run flutter pub get

Explanation The issue is with the new flutter update. They did something whereby certain values aren't hard coded in like they used to be,. Check in the app level build.gradle file. The target SDK number used to be written there as an integer, now, you just see flutter.targetSDK

The way to fix this error you're having is by manually typing these values there.

target sdk version 31 (or 30) min SDK version 16 (use 21 if your project uses google maps)

In the android mainfest file, remove android:name="${applicationName}"

The app will run.