Gradle DSL method not found: 'google()'

报错信息如下：
Gradle DSL method not found: 'google()'
Possible causes:<ul><li>The project 'JustTest' may be using a version of the Android Gradle plug-in that does not contain the method (e.g. 'testCompile' was added in 1.1.0).
Upgrade plugin to version 3.1.2 and sync project</li><li>The project 'JustTest' may be using a version of Gradle that does not contain the method.
Open Gradle wrapper file</li><li>The build file may be missing a Gradle plugin.
Apply Gradle plugin</li>

Analysis of the cause of the error: google() was not found, The google() repo is a shortcut to looks in Google's Maven repository for dependencies. It was introduced with gradle v.4.0. (Conditions of use) It requires (currently) Gradle v.4, Android Studio 3.x., Gradle plugin for Android 3.x

Solution:

• 1. Replace google() with maven {url 'https://maven.google.com'}
• 2. Meet the three conditions for using google() above.