解决gradle下载速度慢

在项目build.gradle中替换

allprojects和buildscript下的

google()/jcenter()

repositories {
        maven { url 'http://maven.aliyun.com/nexus/content/groups/public/'}
        maven { url'https://maven.aliyun.com/repository/public/' }
        maven { url'https://maven.aliyun.com/repository/google/' }
        maven { url'https://maven.aliyun.com/repository/jcenter/' }
        maven { url'https://maven.aliyun.com/repository/central/' }
    }