Why do I get “All com.android.support libraries must use the exact same version specification” in Android Studio 3.2.1?

Question

I have read the article All com.android.support libraries must use the exact same version specification

But I still get the following information after I add the c

Answer 1

I think that play-services-ads:17.0.0 include appcompat 26.1.0. Try to exclude it:

implementation ("com.google.android.gms:play-services-ads:17.0.0") {
    exclude group: "com.android.support"
}