android{
....

applicationVariants.all { variant ->
        variant.outputs.each { output ->
            def outputFile = output.outputFile
            if (outputFile != null && outputFile.name.endsWith('.apk')) {
                File outputDirectory = new File(outputFile.parent);
                def fileName
                if (variant.buildType.name == "release") {
                    fileName = "app_name_v${defaultConfig.versionName}_${variant.productFlavors[0].name}.apk"
                } else {
                    fileName = "app_name_v${defaultConfig.versionName}_beta.apk"
                }
                output.outputFile = new File(outputDirectory, fileName)
            }
        }
    }

....
}

AS3.0需要用这个

applicationVariants.all { variant ->
                variant.outputs.all {
                    
                        def fileName = "great${defaultConfig.versionName}.apk"
                        outputFileName = fileName

                }
            }