failed to resolve: com.android.support:appcompat-v7:27.0.1

出現問題：

Error:(28, 13) Failed to resolve: com.android.support:appcompat-v7:27.0.1
Install Repository and sync project
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解決方法：

在Project級別build.gradle的allprojects內添加maven{url “https://maven.google.com“},然後rebuild project項目即可

allprojects {
    repositories {
        jcenter()
        maven{
            url "https://maven.google.com"
        }
    }
}