mNavigationView = (NavigationView) findViewById(R.id.navigation_view);
    headerView = mNavigationView.inflateHeaderView(R.layout.bp_header);
    googele_plus = (ImageButton) headerView.findViewById(R.id.google_p);
    facebook = (ImageButton) headerViewfindViewById(R.id.fb);

mNavigationView = (NavigationView) findViewById(R.id.navigation_view);
    View headerView = mNavigationView.getHeaderView(0)

    googele_plus = (ImageButton) headerView.findViewById(R.id.google_p);
    facebook = (ImageButton) headerView.findViewById(R.id.fb);

You may have header layout in xml and also you are adding header from java like

    headerView = mNavigationView.inflateHeaderView(R.layout.bp_header);

    So just remove above line from java and add it through the xml
    You can add following in your xml

 <include
 android:id="@+id/header"
 layout="@layout/navigation_header" />

     and then in java create ref like below



      googele_plus = (ImageButton) findViewById(R.id.google_p);
         facebook = (ImageButton) findViewById(R.id.fb);

     Clean and Build the project and then run

headerView = mNavigationView.inflateHeaderView(R.layout.bp_header);

View header = LayoutInflater.from(this).inflate(R.layout.bp_header, null);
mNavigationView.addHeaderView(header);
googele_plus = (ImageButton) header.findViewById(R.id.google_p);