1. AndroidStudio的阿里云镜像配置

第一步：在C:\用户\user.gradle里面新建init.gradle文件（内容如下）

注意：不用进行设置代理，也就时Setting/HTTP Poxy那里设置成no proxy即可

allprojects{
    repositories {
        def ALIYUN_REPOSITORY_URL = 'http://maven.aliyun.com/nexus/content/groups/public'
        def ALIYUN_JCENTER_URL = 'http://maven.aliyun.com/nexus/content/repositories/jcenter'
        all { ArtifactRepository repo ->
            if(repo instanceof MavenArtifactRepository){
                def url = repo.url.toString()
                if (url.startsWith('https://repo1.maven.org/maven2')) {
                    project.logger.lifecycle "Repository ${repo.url} replaced by $ALIYUN_REPOSITORY_URL."
                    remove repo
                }
                if (url.startsWith('https://jcenter.bintray.com/')) {
                    project.logger.lifecycle "Repository ${repo.url} replaced by $ALIYUN_JCENTER_URL."
                    remove repo
                }
            }
        }
        maven {
            url ALIYUN_REPOSITORY_URL
            url ALIYUN_JCENTER_URL
        }
    }
}

第二步：修改工程里面的build.gradle配置

说明：为啥单单修改里面的某一个项目的build.gradle配置就可以对所有项目生效呢？
因为AndroidStudio内置缓存机制，当你重新打开AndroidStudio时就会将build.gradle的配置在所有的项目中重新修改并生效

buildscript {
    repositories {
        maven {
            url "http://maven.aliyun.com/nexus/content/groups/public/"
        }
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:2.3.3'

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        maven {
            url "http://maven.aliyun.com/nexus/content/groups/public/"
        }
        jcenter()
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}

2. Android:gradle 插件版本号与gradle 版本号对应关系

gradle-plugin版本号：在项目的gradle.properties里面
gradle版本号：在builde.gradle里面