我的build.gradle设置

// Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript {
    repositories {
        //阿里云的镜像库
        maven {
            url "http://maven.aliyun.com/nexus/content/groups/public/"
        }
        maven {
            url 'https://maven.fabric.io/public'
        }
        mavenCentral()
        google()
        jcenter()
    }

    dependencies {
        classpath 'com.android.tools.build:gradle:3.6.2'

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

        // The Fabric Gradle plugin uses an open ended version to react
        // quickly to Android tooling updates

        classpath 'com.google.gms:google-services:4.3.3'
    }
}

allprojects {
    repositories {
        //阿里云的镜像库
        //阿里云的镜像库
        maven {
            url "http://maven.aliyun.com/nexus/content/groups/public/"
        }
        maven {
            url 'https://maven.fabric.io/public'
        }
        mavenCentral()
        google()
        jcenter()
    }
}

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