解决Android Studio Gradle Sync同步慢问题

发现阿里云有镜像，只需要添加相应的url地址就可以下载；打开项目build gradle文件。

buildscript {
    
    repositories {
        maven{ url 'http://maven.aliyun.com/nexus/content/groups/public/'}
        google()
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.3.1'
        
 
        // 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/'}
        google()
        jcenter()
    }
}