解决Flutter Could not find lint-gradle-api.jar

1. 在构建flutter开发环境的时候，android studio 报错：

* Error running Gradle:
ProcessException: Process "C:\xxx\Android\flutter_app\android\gradlew.bat" exited abnormally:
 
> Configure project :app
 
Project evaluation failed including an error in afterEvaluate {}. Run with --stacktrace for details of the afterEvaluate {} error.
 
FAILURE: Build failed with an exception.
 
* Where:
Build file 'C:\xxx\Android\flutter_app\android\app\build.gradle' line: 25
 * What went wrong:
A problem occurred evaluating project ':app'.
> Could not resolve all artifacts for configuration 'classpath'.
   > Could not find lint-gradle-api.jar 
     Searched in the following locations:
         https://jcenter.bintray.com/com.android.tools.lint:lint-gradle-api:26.1.2.jar
 * Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.
 
* Get more help at https://help.gradle.org
 BUILD FAILED in 0s
  Command: C:\xxx\Android\flutter_app\android\gradlew.bat app:properties
 
Finished with error: Please review your Gradle project setup in the android/ folder.

2. 一通搜索后提示需要在Project的build.gradle内添加google()，如下：

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

    dependencies {
        classpath 'com.android.tools.build:gradle:3.1.2'
    }
}

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

buildscript {
    repositories {//        jcenter()
        maven{ url 'https://maven.aliyun.com/repository/google' }
        maven{ url 'https://maven.aliyun.com/repository/jcenter' }
        maven{url 'http://maven.aliyun.com/nexus/content/groups/public'}        //maven {
          //  url 'https://dl.google.com/dl/android/maven2'
        //}
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.1.2'
    }
}