Could not resolve all artifacts for configuration ‘:classpath‘安卓报错解决方法

跑一个项目，从谷歌下载一个aar怎么也下载不下来，总是失败，添加阿里云镜像打开项目编译后发现：Could not resolve all artifacts for configuration ':classpath'；不能解析classpath，然后常规clean、rebuild、offline work、修改本地gradle...一番操作之后，依然没用。最后上google寻求帮助，成功解决了这个问题原因还是网络问题，资源库加载不下来。

解决办法如下：在根目录的build文件里加上这几句镜像代码，重新编译解决，墙.是硬伤

repositories {
      //  google()
        maven { url 'http://maven.aliyun.com/nexus/content/groups/public/' }
        maven { url 'http://maven.aliyun.com/nexus/content/repositories/jcenter' }
        maven { url 'http://maven.aliyun.com/nexus/content/repositories/google' }
        maven { url 'http://maven.aliyun.com/nexus/content/repositories/gradle-plugin' }
        jcenter()
        maven { url "https://jitpack.io" }
        
    }

allprojects {
    repositories {
        maven { url 'http://maven.aliyun.com/nexus/content/groups/public/