public class HostBean implements Parcelable {

    public static final String EXTRA = ActivityMain.PKG + ".extra";
    public static final String EXTRA_POSITION = ActivityMain.PKG + ".extra_position";
    public static final String EXTRA_HOST = ActivityMain.PKG + ".extra_host";
    public static final String EXTRA_TIMEOUT = ActivityMain.PKG + ".network.extra_timeout";
    public static final String EXTRA_HOSTNAME = ActivityMain.PKG + ".extra_hostname";
    public static final String EXTRA_BANNERS = ActivityMain.PKG + ".extra_banners";
    public static final String EXTRA_PORTSO = ActivityMain.PKG + ".extra_ports_o";
    public static final String EXTRA_PORTSC = ActivityMain.PKG + ".extra_ports_c";
    public static final String EXTRA_SERVICES = ActivityMain.PKG + ".extra_services";
    public static final int TYPE_GATEWAY = 0;
    public static final int TYPE_COMPUTER = 1;

    public int deviceType = TYPE_COMPUTER;
    public int isAlive = 1;
    public int position = 0;
    public int responseTime = 0; // ms
    public String ipAddress = null;
    public String hostname = null;
    public String hostsection = null;
    public String hardwareAddress = NetInfo.NOMAC;
    public String nicVendor = "Unknown";
    public String os = "Unknown";
    public HashMap<Integer, String> services = null;
    public HashMap<Integer, String> banners = null;
    public ArrayList<Integer> portsOpen = null;
    public ArrayList<Integer> portsClosed = null;

    public HostBean() {
        // New object
    }

    public HostBean(Parcel in) {
        // Object from parcel
        readFromParcel(in);
    }

    public int describeContents() {
        return 0;
    }

    public void writeToParcel(Parcel dest, int flags) {
        dest.writeInt(deviceType);
        dest.writeInt(isAlive);
        dest.writeString(ipAddress);
        dest.writeString(hostname);
        dest.writeString( hostsection );
        dest.writeString(hardwareAddress);
        dest.writeString(nicVendor);
        dest.writeString(os);
        dest.writeInt(responseTime);
        dest.writeInt(position);
        dest.writeMap(services);
        dest.writeMap(banners);
        dest.writeList(portsOpen);
        dest.writeList(portsClosed);
    }

    private void readFromParcel(Parcel in) {
        deviceType = in.readInt();
        isAlive = in.readInt();
        ipAddress = in.readString();
        hostname = in.readString();
        hardwareAddress = in.readString();
        nicVendor = in.readString();
        os = in.readString();
        hostsection=in.readString();
        responseTime = in.readInt();
        position = in.readInt();
        services = in.readHashMap(null);
        banners = in.readHashMap(null);
        portsOpen = in.readArrayList(Integer.class.getClassLoader());
        portsClosed = in.readArrayList(Integer.class.getClassLoader());
    }

    @SuppressWarnings("unchecked")
    public static final Creator CREATOR = new Creator() {
        public HostBean createFromParcel(Parcel in) {
            return new HostBean(in);
        }

        public HostBean[] newArray(int size) {
            return new HostBean[size];
        }
    };
}

public class SimpleAdapter extends RecyclerView.Adapter<SimpleAdapter.SimpleViewHolder> {

    private final Context mContext;
    private ArrayList<HostBean> mData;
    final HostBean host = new HostBean();
    public void add(HostBean s,int position) {
        position = position == -1 ? getItemCount()  : position;
        host.hostsection=s;
        mData.add(position,s);
        notifyItemInserted(position);
    }

    public void remove(int position){
        if (position < getItemCount()  ) {
            mData.remove(position);
            notifyItemRemoved(position);
        }
    }

    public static class SimpleViewHolder extends RecyclerView.ViewHolder {
        public final TextView mac;
        public final TextView vendor;
        public final TextView ip;

        public SimpleViewHolder(View view) {
            super(view);
            ip = (TextView) view.findViewById(R.id.ip);
            mac = (TextView) view.findViewById(R.id.mac);
            vendor = (TextView) view.findViewById(R.id.vendor);
        }
    }

    public SimpleAdapter(Context context, List<HostBean> data) {
        mContext = context;
        if (data != null)
            mData = new ArrayList<HostBean>();
    }

    public SimpleViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        final View view = LayoutInflater.from(mContext).inflate(R.layout.list_host, parent, false);
        return new SimpleViewHolder(view);
    }

    @Override
    public void onBindViewHolder(SimpleViewHolder holder, final int position) {
        holder.ip.setText( (CharSequence) mData.get(position) );
        holder.mac.setText( "" );
        holder.vendor.setText( "" );
    }

    @Override
    public int getItemCount() {
        return mData.size();
    }
}

public class SimpleSectionedRecyclerViewAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {

    private final Context mContext;
    private static final int SECTION_TYPE = 0;

    private boolean mValid = true;
    private int mSectionResourceId;
    private int mTextResourceId;
    private LayoutInflater mLayoutInflater;
    private RecyclerView.Adapter mBaseAdapter;
    private SparseArray<Section> mSections = new SparseArray<Section>();


    public SimpleSectionedRecyclerViewAdapter(Context context, int sectionResourceId, int textResourceId,
                                              RecyclerView.Adapter baseAdapter) {

        mLayoutInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        mSectionResourceId = sectionResourceId;
        mTextResourceId = textResourceId;
        mBaseAdapter = baseAdapter;
        mContext = context;

        mBaseAdapter.registerAdapterDataObserver(new RecyclerView.AdapterDataObserver() {
            @Override
            public void onChanged() {
                mValid = mBaseAdapter.getItemCount()>0;
                notifyDataSetChanged();
            }

            @Override
            public void onItemRangeChanged(int positionStart, int itemCount) {
                mValid = mBaseAdapter.getItemCount()>0;
                notifyItemRangeChanged(positionStart, itemCount);
            }

            @Override
            public void onItemRangeInserted(int positionStart, int itemCount) {
                mValid = mBaseAdapter.getItemCount()>0;
                notifyItemRangeInserted(positionStart, itemCount);
            }

            @Override
            public void onItemRangeRemoved(int positionStart, int itemCount) {
                mValid = mBaseAdapter.getItemCount()>0;
                notifyItemRangeRemoved(positionStart, itemCount);
            }
        });
    }


    public static class SectionViewHolder extends RecyclerView.ViewHolder {

        public TextView title;

        public SectionViewHolder(View view, int mTextResourceid) {
            super(view);
            title = (TextView) view.findViewById(mTextResourceid);
        }
    }

    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int typeView) {
        if (typeView == SECTION_TYPE) {
            final View view = LayoutInflater.from(mContext).inflate(mSectionResourceId, parent, false);
            return new SectionViewHolder(view,mTextResourceId);
        }else{
            return mBaseAdapter.onCreateViewHolder(parent, typeView -1);
        }
    }

    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder sectionViewHolder, int position) {
        if (isSectionHeaderPosition(position)) {
            ((SectionViewHolder)sectionViewHolder).title.setText(mSections.get(position).title);
        }else{
            mBaseAdapter.onBindViewHolder(sectionViewHolder,sectionedPositionToPosition(position));
        }

    }

    @Override
    public int getItemViewType(int position) {
        return isSectionHeaderPosition(position)
                ? SECTION_TYPE
                : mBaseAdapter.getItemViewType(sectionedPositionToPosition(position)) +1 ;
    }


    public static class Section {
        int firstPosition;
        int sectionedPosition;
        CharSequence title;

        public Section(int firstPosition, CharSequence title) {
            this.firstPosition = firstPosition;
            this.title = title;
        }

        public CharSequence getTitle() {
            return title;
        }
    }


    public void setSections(Section[] sections) {
        mSections.clear();

        Arrays.sort(sections, new Comparator<Section>() {
            @Override
            public int compare(Section o, Section o1) {
                return (o.firstPosition == o1.firstPosition)
                        ? 0
                        : ((o.firstPosition < o1.firstPosition) ? -1 : 1);
            }
        });

        int offset = 0; // offset positions for the headers we're adding
        for (Section section : sections) {
            section.sectionedPosition = section.firstPosition + offset;
            mSections.append(section.sectionedPosition, section);
            ++offset;
        }

        notifyDataSetChanged();
    }

    public int positionToSectionedPosition(int position) {
        int offset = 0;
        for (int i = 0; i < mSections.size(); i++) {
            if (mSections.valueAt(i).firstPosition > position) {
                break;
            }
            ++offset;
        }
        return position + offset;
    }

    public int sectionedPositionToPosition(int sectionedPosition) {
        if (isSectionHeaderPosition(sectionedPosition)) {
            return RecyclerView.NO_POSITION;
        }

        int offset = 0;
        for (int i = 0; i < mSections.size(); i++) {
            if (mSections.valueAt(i).sectionedPosition > sectionedPosition) {
                break;
            }
            --offset;
        }
        return sectionedPosition + offset;
    }

    public boolean isSectionHeaderPosition(int position) {
        return mSections.get(position) != null;
    }


    @Override
    public long getItemId(int position) {
        return isSectionHeaderPosition(position)
                ? Integer.MAX_VALUE - mSections.indexOfKey(position)
                : mBaseAdapter.getItemId(sectionedPositionToPosition(position));
    }

    @Override
    public int getItemCount() {
        return (mValid ? mBaseAdapter.getItemCount() + mSections.size() : 0);
    }

}

hosts = new ArrayList<HostBean>();

RecyclerView list =findViewById(R.id.output);
        list.setHasFixedSize( true );
        list.setLayoutManager( new LinearLayoutManager( this ) );
        list.addItemDecoration(new DividerItemDecoration(this,LinearLayoutManager.VERTICAL));
        SimpleAdapter mAdapter = new SimpleAdapter(this,hosts);

        List<SimpleSectionedRecyclerViewAdapter.Section> sections =
                new ArrayList<SimpleSectionedRecyclerViewAdapter.Section>();

        //Sections
        sections.add(new SimpleSectionedRecyclerViewAdapter.Section(0,"Know Devices"));
        sections.add(new SimpleSectionedRecyclerViewAdapter.Section(5,"Unknown Devices"));
        SimpleSectionedRecyclerViewAdapter.Section[] dummy = new SimpleSectionedRecyclerViewAdapter.Section[sections.size()];
        SimpleSectionedRecyclerViewAdapter mSectionedAdapter = new
                SimpleSectionedRecyclerViewAdapter(this,R.layout.section,R.id.section_text,mAdapter);
        mSectionedAdapter.setSections(sections.toArray(dummy));
        list.setAdapter( mSectionedAdapter );