Attribute application@name at AndroidManifest.xml:5:9-42 requires a placeholder substitution but no value for <applicationName> is provided. - Flutter

Question

Upon running a project I'm getting following error.

Launching lib\main.dart on SM N970F in debug mode...
lib\main.dart:1
Parameter format not correct -
D:\CIIT GUIDE\Flutter\Apps\multi_delivery_app\android\app\src\main\AndroidManifest.xml:5:9-42 Error:
    Attribute application@name at AndroidManifest.xml:5:9-42 requires a placeholder substitution but no value for <applicationName> is provided.
D:\CIIT GUIDE\Flutter\Apps\multi_delivery_app\android\app\src\debug\AndroidManifest.xml Error:
    Validation failed, exiting

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':app:processDebugMainManifest'.
> 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

This is how build.gradle looks like in android/app.

android {
    compileSdkVersion 29
    // buildToolsVersion '26.0.3'

    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }

    kotlinOptions {
        jvmTarget = '1.8'
    }

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

    defaultConfig {
        applicationId "com.example.multi_delivery_app"
        minSdkVersion 28
        targetSdkVersion 29
        versionCode flutterVersionCode.toInteger()
        versionName flutterVersionName
        // Stackoverflow solution
        manifestPlaceholders = [appAuthRedirectScheme: "com.example.multi_delivery_app"]   
    }

    buildTypes {
        release {
            signingConfig signingConfigs.debug
        }
    }

I found a couple of solutions of it online, which are related to react-native but nothing is working. Following is the link of the solution that I tried. https://stackoverflow.com/a/52178888/7290043

Answer 1

You can add the appAuthRedirectScheme attributes to the manifestPlaceholders instead of replacing the whole array, by using += instead of =

Example :

defaultConfig {
    ...
    manifestPlaceholders += [appAuthRedirectScheme: "com.example.multi_delivery_app"]
}

Answer 2

I think in build.gradle should add the applicationName key with the full name of the Android Application class (which extends the FlutterApplication)

For example:

defaultConfig {
    ...
    manifestPlaceholders = [appAuthRedirectScheme: "com.example.multi_delivery_app", 
                            applicationName: "com.example.multi_delivery_app.Application"]
}