Grid Layout with Header

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@android:color/white"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin">

    <android.support.v7.widget.RecyclerView
        android:id="@+id/recycler_view"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

</RelativeLayout>

grid_element.xml

<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_margin="5dp"
    android:background="@color/material_blue_grey_800"
    android:padding="10dp"
    android:textColor="@android:color/holo_orange_light" />

MainActivity.java

package ws.otero.adrian.gridexample;

import android.graphics.Color;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;


public class MainActivity extends ActionBarActivity {


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);


        TextView header = new TextView(this);
        header.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT));
        header.setTextColor(Color.parseColor("#000000"));
        header.setText("This is the header");

        RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recycler_view);
        recyclerView.setHasFixedSize(true);

        GridLayoutManager gridLayoutManager = new GridLayoutManager(this, 2);
        gridLayoutManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
            @Override
            public int getSpanSize(int position) {
                return position == 0 ? 2 : 1;
            }
        });
        recyclerView.setLayoutManager(gridLayoutManager);

        ElementsAdapter elementsAdapter = new ElementsAdapter(5);
        elementsAdapter.setHeader(header);

        recyclerView.setAdapter(elementsAdapter);

    }

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

        private static final int VIEW_HEADER = 0;
        private static final int VIEW_NORMAL = 1;

        private View headerView;
        private int datasetSize;

        public class HeaderViewHolder extends RecyclerView.ViewHolder {
            public HeaderViewHolder(View v) {
                super(v);
            }
        }

        public class ViewHolder extends RecyclerView.ViewHolder {

            public TextView textView;

            public ViewHolder(TextView v) {
                super(v);
                textView = v;
            }
        }

        public ElementsAdapter(int size) {
            this.datasetSize = size;
        }

        public void setHeader(View v) {
            this.headerView = v;
        }

        @Override
        public int getItemViewType(int position) {
            return position == 0 ? VIEW_HEADER : VIEW_NORMAL;
        }

        @Override
        public int getItemCount() {
            return datasetSize + 1;
        }

        @Override
        public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
            if (viewType == VIEW_HEADER) {
                return new HeaderViewHolder(headerView);

            } else {
                TextView textView = (TextView) LayoutInflater.from(parent.getContext()).inflate(R.layout.grid_element, parent, false);
                return new ViewHolder(textView);
            }
        }

        @Override
        public void onBindViewHolder(RecyclerView.ViewHolder viewHolder, int position) {

            if (position == 0) return;

            ViewHolder holder = (ViewHolder) viewHolder;
            holder.textView.setText("Position " + (position - 1));

        }
    }
}