Cannot resolve symbol Youtube in Android -

i frustrated followed steps add google api youtube in android project , still having error: cannot resolve symbol youtube

here java class:

  import android.app.activity; import android.os.bundle; import android.widget.gridview;  import com.google.android.youtube.player.youtubeplayer; import com.google.android.youtube.player.youtubethumbnailloader; import  com.google.api.services.youtube.youtube;   import java.util.list;     public class videocatalogactivity extends activity implements youtubethumbnailloader, youtubeplayer{      private static final string tag =  videocatalogactivity.class.getsimplename();      private static youtube youtube;      gridview videosgrid;      @override     protected void oncreate(bundle savedinstancestate) {          super.oncreate(savedinstancestate);     } 

and app gradle file:

     buildtypes {         release {             minifyenabled false             proguardfiles getdefaultproguardfile('proguard-android.txt'), 'proguard-rules.pro'         }         debug {             debuggable true         }      } }  dependencies {     compile filetree(include: ['*.jar'], dir: 'libs')     compile files('libs/youtubeandroidplayerapi.jar')     compile files('libs/picasso-2.4.0.jar')     compile 'com.android.support:appcompat-v7:24.2.0'     compile 'com.android.support:recyclerview-v7:24.2.0'     compile 'com.facebook.android:facebook-android-sdk:[4,5)'     compile 'com.google.firebase:firebase-core:9.4.0'     compile 'com.google.firebase:firebase-auth:9.4.0'     compile 'com.google.android.gms:play-services-auth:9.4.0'     compile 'com.google.apis:google-api-services-youtube:v3-rev178-1.22.0'      testcompile 'junit:junit:4.12'  }  apply plugin: 'com.google.gms.google-services' 

what doing wrong ?

any appreciated !

i solved problem declaration wrong: had declare youtube youtube object not youtube.