在app下面的build.gradle文件中,添加如下代码即可,如图:

studio3.0以前,添加:

            applicationVariants.all { variant ->
                variant.outputs.each { output ->
                    def outputFile = output.outputFile
                    if (outputFile != null && outputFile.name.endsWith('.apk')) {
                        // 输出apk名称为BoLanHui_v1.0_2015-01-15.apk
                        def fileName = "BoLanHui_v${defaultConfig.versionName}_${releaseTime()}.apk"
                        output.outputFile = new File(outputFile.parent, fileName)
                    }
                }
            }

studio3.0以后,添加:

            applicationVariants.all { variant ->
                variant.outputs.all {
                    // 输出apk名称为WeiLaiCheng1.0_2018-08-13.apk
                    def fileName = "WeiLaiCheng${defaultConfig.versionName}_${releaseTime()}.apk"
                    outputFileName = fileName
                }
            }

其中releaseTime()为获取当前时间,加在  android{...} 以外 , 代码:

def releaseTime() {
    return new Date().format("yyyy-MM-dd")
}