com.google.android.gms.ads.AdView could not be found Android Studio

Question

I've been researching for days trying to figure this out. Anything to do with Google Play Services is colored red. It's in the Gradle already the most up-to-date version I've got all the pieces the websites says to put there and it's still red.

import android.widget.Button;
import android.widget.Toast;
import com.example.zanziv.rickandmorty.R;
import com.google.android.gms.ads.AdRequest;
import com.google.android.gms.ads.AdView;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GooglePlayServicesUtil;
import java.io.IOException;

 public class MainActivity extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);



            AdView mAdView = (AdView)findViewById(R.id.adView);
            AdRequest.Builder adRequestBuilder = new AdRequest.Builder();
            mAdView.loadAd(adRequestBuilder.build());

dependencies

dependencies {
compile fileTree(include: ['*.jar'], dir: 'libs')
compile 'com.android.support:appcompat-v7:23.0.1'
compile 'com.google.android.gms:play-services:7.8.0'
compile 'com.google.android.gms:play-services-ads:7.8.0'

xml

 <com.google.android.gms.ads.AdView
    xmlns:ads="http://schemas.android.com/apk/res-auto"
    android:id="@+id/adView"
    android:layout_width="320dp"
    android:layout_height="50dp"
    ads:adSize="BANNER"
    ads:adUnitId="MINE"
    android:layout_alignParentBottom="true"
    android:layout_centerHorizontal="true">
</com.google.android.gms.ads.AdView>

Answer 1

Did you add the SDK tools beforehand?
Go on SDK Manager > Extras > Select Google Repository and Google Play services and install them.

For more details, read this document.