Android studio Could not resolve all files for configuration ':app:debugCompileClasspath'.等

 repositories {
        google()
        jcenter()
        maven{ url 'https://maven.aliyun.com/repository/google'}
    }

 repositories {
        google()
        jcenter()
        maven { url "https://jitpack.io" }
        maven{ url 'https://maven.aliyun.com/repository/google'}
    }

加上google这个配置就好了。