AndroidStudio3.0 Unable to resolve dependency for ':app@debug/compileClasspath': Could not find any

更新AndroidStudio后一片飘红

Error:Unable to resolve dependency for ':app@debug/compileClasspath': Could not resolve com.android.support:appcompat-v7:26.1.0. Open File
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Error:Unable to resolve dependency for ':app@debugAndroidTest/compileClasspath': Could not resolve com.android.support.test:runner:1.0.1. Open File
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Error:Unable to resolve dependency for ':app@debugAndroidTest/compileClasspath': Could not resolve com.android.support.test.espresso:espresso-core:3.0.1. Open File
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原因：as build 配置问题

build.gradle添加这句话
repositories {
        google()
        jcenter()
    }

重新build一下就行了