加入recyclerview时，出现了“Unable to resolve dependency for ':app@debug/compileClasspath': Could not resolve com.android.support:recyclerview-v7:27.1.1.”错误，查了半天没找到相应的版本号，最好直接找现成的，3.0加入的方法很简单：
1.在studio 最上面的导航栏里面找到 build ，然后点击build，
2.然后找到 "Edit Libraries and Dependencies" 点击，
3，在弹出来的框右上角有个加号，点击
4，选择Library Dependency
5,输入recycler
6，回车或者点击搜索，然后选择结果就行了
you can also add lib/dependencies from android studio menu.
click on "Build" -> "Edit Libraries and Dependencies". then click on "+" button on right side.
search any lib.
example search "recycler"
then select "com.android.support:recyclerview-v7:x.x.x" from list and your done.
转载的地址 https://stackoverflow.com/questions/37612348/how-to-add-the-recyclerview-to-project