Android Studio failed to resolve .....

今天导入一个项目到AS，项目的build.gradle中：

dependencies {
compile fileTree(include: ['*.jar'], dir: 'libs')
compile project(':library')
compile 'com.android.support:recyclerview-v7:23.1.1'
compile 'com.android.support:appcompat-v7:23.1.1'
}

Gradle Sync的时候报错：

failed to resolve 'com.android.support:recyclerview-v7:23.1.1'

failed to resolve 'com.android.support:appcompat-v7:23.1.1'  

解决方法：

到SDK界面查看是否安装了

Android
Support Repository

Android
Support Library  ——
 现在好像已经更名为：Local
Maven Repository for Support Libraries

没有的话下载安装后，重新编译运行就行了