来自文档:-

您的应用 gradle 文件现在必须明确列出 com.google.firebase:firebase-core 作为 Firebase 服务按预期工作的依赖项.

Your app gradle file now has to explicitly list com.google.firebase:firebase-core as a dependency for Firebase services to work as expected.

添加:

 implementation 'com.google.firebase:firebase-core:16.0.1'

并在*** gradle 文件中使用最新版本的 google play 服务:

and in top level gradle file use the latest version of google play services:

classpath 'com.google.gms:google-services:4.0.2'

https://firebase.google.com/support/release-notes/android

https://bintray.com/android/android-工具/com.google.gms.google-services

注意:

您需要在*** gradle 文件中添加 google() 存储库，如 firebase 文档中所述，并且它应该在 jcenter() 之前:

You need to add the google() repo in the top level gradle file, as specified in the firebase docs and also it should be before jcenter():

 buildscript {
  repositories {
          google()
          jcenter()
      }



dependencies {
  classpath 'com.android.tools.build:gradle:3.1.3'
  classpath 'com.google.gms:google-services:4.0.2'
   }
}

allprojects {
     repositories {
              google()
             jcenter()
  }
}

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

https://firebase.google.com/docs/android/setup