1，解決依賴鏡像問題

buildscript {
   repositories {
       mavenCentral()
       google()
//        jcenter()
       maven{ url'http://maven.aliyun.com/nexus/content/groups/public/' }
       maven{ url'http://maven.aliyun.com/nexus/content/repositories/jcenter'}
   }
   dependencies {
       classpath 'com.android.tools.build:gradle:3.0.1'
   }
}