GooglePlayServicesUtil vs GoogleApiAvailability

I have found the solution. In the GoogleApiAvailability, all methods are public method, while in GooglePlayServicesUtil all methods are static public function.

So to use GoogleApiAvailability, the right way is:

private boolean checkPlayServices() {
    GoogleApiAvailability googleAPI = GoogleApiAvailability.getInstance();
    int result = googleAPI.isGooglePlayServicesAvailable(this);
    if(result != ConnectionResult.SUCCESS) {
        if(googleAPI.isUserResolvableError(result)) {
            googleAPI.getErrorDialog(this, result,
                    PLAY_SERVICES_RESOLUTION_REQUEST).show();
        }

        return false;
    }

    return true;
}