Use different google-services.json for different app flavors on Android.

gistfile1.txt

def appModuleRootFolder = '.'
def srcDir = 'src'
def googleServicesJson = 'google-services.json'

task switchToStaging(type: Copy) {
    outputs.upToDateWhen { false }
    def flavor = 'staging'
    description = "Switches to $flavor $googleServicesJson"
    delete "$appModuleRootFolder/$googleServicesJson"
    from "${srcDir}/$flavor/"
    include "$googleServicesJson"
    into "$appModuleRootFolder"
}

task switchToProduction(type: Copy) {
    outputs.upToDateWhen { false }
    def flavor = 'production'
    description = "Switches to $flavor $googleServicesJson"
    from "${srcDir}/$flavor/"
    include "$googleServicesJson"
    into "$appModuleRootFolder"
}

afterEvaluate {
    processStagingDebugGoogleServices.dependsOn switchToStaging
    processStagingReleaseGoogleServices.dependsOn switchToStaging
    processProductionDebugGoogleServices.dependsOn switchToProduction
    processProductionReleaseGoogleServices.dependsOn switchToProduction
}