Why does Gradle warn about manifestPlaceholders in Android?

Question

I am currently working on an Android Kotlin project. In this project, I need to retrieve certain keys from the local.properties file and subsequently utilize them in the AndroidManifest.xml file. However, I have encountered an issue where I receive a warning stating that

'property 'googleMapsApiKey' does not exist'.

I have attempted to resolve this problem by cleaning and rebuilding the project, but unfortunately, I have not been successful. Below is the code snippet in question:

Gradle (App Level) code :

defaultConfig {
        applicationId "com.testapp.myfirstapp"
        minSdk 23
        targetSdk 34
        versionCode 8
        versionName "1.0.0"

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"

        Properties properties = new Properties()
        properties.load(project.rootProject.file('local.properties').newDataInputStream())
        
        if (properties.containsKey('MAPS_API_KEY')) {
            manifestPlaceholders = [googleMapsApiKey: "${properties.getProperty('MAPS_API_KEY')}"]
        } else {
            println "Warning: MAPS_API_KEY not found in local.properties"
        }
    }

local.properties code :

MAPS_API_KEY=APIkeysssd1201232ApiTestKeyStack

manifest code :

<meta-data
            android:name="com.google.android.geo.API_KEY"
            android:value="${googleMapsApiKey}" />

Answer 1

Having the same problem. The IDE suggestion creates a "Dynamic Member" which got rid of the warning as mentioned. But since I could not find any documentation how these "Dynamic Members" work, I went with a different way of defining the placeholder, which also does not raise any Lint warning:

manifestPlaceholders["key"] = "value"