This is my build.gradle
apply plugin: \'com.android.application\' android { compileSdkVersion 25 buildToolsVersion \"26.0.2\" android {
All support libraries need to be same version. If your compile SDK is 25,it's 25.3.0. If your compile SDK is 26, it's 26.0.0. Don't mix them
support
this should fix your problem
compile 'com.android.support:appcompat-v7:25.3.0' compile 'com.android.support:recyclerview-v7:25.3.0'