Change output apk name using build.gradle

Output result:  AppNameProd4.1.2_050718.apk

android {
    applicationVariants.all { variant ->
        variant.outputs.all {
            def flavor = variant.productFlavors[0].name.capitalize()
            def version = variant.versionName
            def date = new Date()
            def formattedDate = date.format('ddMMyy')
            outputFileName = "AppName${flavor}${version}_${formattedDate}.apk"
        }
    }
}

If you need a buildType name:

def buildType = variant.variantData.variantConfiguration.buildType.name

Version code:

def versionCode = variant.versionCode