How to implement app indexing plugin, by using Prime31 UnityPlayerActivity?

I am implementing the App indexing plugin, using Prime 31 UnityPlayerActivity which is implemented by overriding Androinds onCreate, onStop methods etc, but when I use this keyword in onCreate method it is showing me an error.

private GoogleApiClient mClient;
private String mUrl;
private String mTitle;
private String mDescription;

@Override
protected void onCreate(Bundle savedInstanceState)
{
    Log.d("onCreate","in oncreate method");
    super.onCreate(savedInstanceState);
    mClient = new GoogleApiClient.Builder(this).addApi(AppIndex.API).build();

at Builder(this) it is showing syntax error ..

Currently I am developing an App indexing Auto complete feature in to my game, for that I created a demo Unity project created the plugin for app indexing, and while creating the plugin I extended my class with UnityPlayerActivity which is came from il2cpp's classes.jar, but in our game we used Prime 31 plugins, prime31 documentation says that,

"Any other third party (non prime[31]) plugins that do override the main Unity Activity will not work in the same game. In order to facilate compatibility for all Unity plugins we developed an Activity sharing system that is freely available for anyone (including other plugin vendors) to use."

so I included prime31UnityActivity.jar in libs directory of Android but I am not able to find instance of the extended class, I am getting a syntax error at keyword this.

public static void onCreate(Bundle savedInstanceState)
{

    Log.d("onCreate","in oncreate method");

    //super.onCreate(savedInstanceState);

    mClient = new GoogleApiClient.Builder(this).addApi(AppIndex.API).build();
}