Sticky Header Smooth Recycler view in Android

> Here is the example of Sticky Header view in recycler view with smooth scroll

> Sticky header is a View over recycler view that will Stick on header of recycler view and shows some information

> In this example i have filtered out the alphabets that will stick on header of recycler view.

> Follow the following Steps to make a Recycler View with Sticky Header.

	<?xml version="1.0" encoding="utf-8"?>
	<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
	xmlns:tools="http://schemas.android.com/tools"
	android:layout_width="match_parent"
	android:layout_height="match_parent"
	tools:context=".MainActivity">
	<android.support.v7.widget.RecyclerView
	android:id="@+id/recyclerview"
	android:layout_width="match_parent"
	android:layout_height="match_parent"
	android:layout_marginTop="50dp"
	android:clipToPadding="true"
	android:saveEnabled="false" />
	</RelativeLayout>

view raw activity_main.xml hosted with ❤ by GitHub

	import android.content.Context;
	import android.support.v7.widget.RecyclerView;
	import android.view.LayoutInflater;
	import android.view.View;
	import android.view.ViewGroup;
	import android.widget.TextView;
	import java.util.ArrayList;
	public class Adapter extends RecyclerView.Adapter<Adapter.Holder> {
	Context mContext;
	ArrayList<String> mArrayListString;
	public Adapter(Context mContext, ArrayList<String> mArrayListString) {
	this.mContext = mContext;
	this.mArrayListString = mArrayListString;
	}
	@Override
	public Holder onCreateViewHolder(ViewGroup parent, int viewType) {
	View view = LayoutInflater.from(mContext).inflate(R.layout.view_item, parent, false);
	return new Holder(view);
	}
	@Override
	public void onBindViewHolder(Holder holder, int position) {
	holder.mTextView.setText(mArrayListString.get(position));
	}
	@Override
	public int getItemCount() {
	return mArrayListString.size();
	}
	public class Holder extends RecyclerView.ViewHolder {
	private final TextView mTextView;
	public Holder(View itemView) {
	super(itemView);
	mTextView = (TextView) itemView.findViewById(R.id.tv_item);
	}
	}
	}

view raw Adapter.java hosted with ❤ by GitHub

	<?xml version="1.0" encoding="utf-8"?>
	<resources>
	<string-array name="animals">
	<item>Abyssinian</item>
	<item>Adelie Penguin</item>
	<item>Affenpinscher</item>
	<item>Afghan Hound</item>
	<item>African Bush Elephant</item>
	<item>African Civet</item>
	<item>African Clawed Frog</item>
	<item>African Forest Elephant</item>
	<item>African Palm Civet</item>
	<item>African Penguin</item>
	<item>African Tree Toad</item>
	<item>African Wild Dog</item>
	<item>Ainu Dog</item>
	<item>Airedale Terrier</item>
	<item>Akbash</item>
	<item>Akita</item>
	<item>Alaskan Malamute</item>
	<item>Albatross</item>
	<item>Aldabra Giant Tortoise</item>
	<item>Alligator</item>
	<item>Alpine Dachsbracke</item>
	<item>American Bulldog</item>
	<item>American Cocker Spaniel</item>
	<item>American Coonhound</item>
	<item>American Eskimo Dog</item>
	<item>American Foxhound</item>
	<item>American Pit Bull Terrier</item>
	<item>American Staffordshire Terrier</item>
	<item>American Water Spaniel</item>
	<item>Anatolian Shepherd Dog</item>
	<item>Angelfish</item>
	<item>Ant</item>
	<item>Anteater</item>
	<item>Antelope</item>
	<item>Appenzeller Dog</item>
	<item>Arctic Fox</item>
	<item>Arctic Hare</item>
	<item>Arctic Wolf</item>
	<item>Armadillo</item>
	<item>Asian Elephant</item>
	<item>Asian Giant Hornet</item>
	<item>Asian Palm Civet</item>
	<item>Asiatic Black Bear</item>
	<item>Australian Cattle Dog</item>
	<item>Australian Kelpie Dog</item>
	<item>Australian Mist</item>
	<item>Australian Shepherd</item>
	<item>Australian Terrier</item>
	<item>Avocet</item>
	<item>Axolotl</item>
	<item>Aye Aye</item>
	<item>Baboon</item>
	<item>Bactrian Camel</item>
	<item>Badger</item>
	<item>Balinese</item>
	<item>Banded Palm Civet</item>
	<item>Bandicoot</item>
	<item>Barb</item>
	<item>Barn Owl</item>
	<item>Barnacle</item>
	<item>Barracuda</item>
	<item>Basenji Dog</item>
	<item>Basking Shark</item>
	<item>Basset Hound</item>
	<item>Bat</item>
	<item>Bavarian Mountain Hound</item>
	<item>Beagle</item>
	<item>Bear</item>
	<item>Bearded Collie</item>
	<item>Bearded Dragon</item>
	<item>Beaver</item>
	<item>Bedlington Terrier</item>
	<item>Beetle</item>
	<item>Bengal Tiger</item>
	<item>Bernese Mountain Dog</item>
	<item>Bichon Frise</item>
	<item>Binturong</item>
	<item>Bird</item>
	<item>Birds Of Paradise</item>
	<item>Birman</item>
	<item>Bison</item>
	<item>Black Bear</item>
	<item>Black Rhinoceros</item>
	<item>Black Russian Terrier</item>
	<item>Black Widow Spider</item>
	<item>Bloodhound</item>
	<item>Blue Lacy Dog</item>
	<item>Blue Whale</item>
	<item>Bluetick Coonhound</item>
	<item>Bobcat</item>
	<item>Bolognese Dog</item>
	<item>Bombay</item>
	<item>Bongo</item>
	<item>Bonobo</item>
	<item>Booby</item>
	<item>Border Collie</item>
	<item>Border Terrier</item>
	<item>Bornean Orang-utan</item>
	<item>Borneo Elephant</item>
	<item>Boston Terrier</item>
	<item>Bottle Nosed Dolphin</item>
	<item>Boxer Dog</item>
	<item>Boykin Spaniel</item>
	<item>Brazilian Terrier</item>
	<item>Brown Bear</item>
	<item>Budgerigar</item>
	<item>Buffalo</item>
	<item>Bull Mastiff</item>
	<item>Bull Shark</item>
	<item>Bull Terrier</item>
	<item>Bulldog</item>
	<item>Bullfrog</item>
	<item>Bumble Bee</item>
	<item>Burmese</item>
	<item>Burrowing Frog</item>
	<item>Butterfly</item>
	<item>Butterfly Fish</item>
	<item>Caiman</item>
	<item>Caiman Lizard</item>
	<item>Cairn Terrier</item>
	<item>Camel</item>
	<item>Canaan Dog</item>
	<item>Capybara</item>
	<item>Caracal</item>
	<item>Carolina Dog</item>
	<item>Cassowary</item>
	<item>Cat</item>
	<item>Caterpillar</item>
	<item>Catfish</item>
	<item>Cavalier King Charles Spaniel</item>
	<item>Centipede</item>
	<item>Cesky Fousek</item>
	<item>Chameleon</item>
	<item>Chamois</item>
	<item>Cheetah</item>
	<item>Chesapeake Bay Retriever</item>
	<item>Chicken</item>
	<item>Chihuahua</item>
	<item>Chimpanzee</item>
	<item>Chinchilla</item>
	<item>Chinese Crested Dog</item>
	<item>Chinook</item>
	<item>Chinstrap Penguin</item>
	<item>Chipmunk</item>
	<item>Chow Chow</item>
	<item>Cichlid</item>
	<item>Clouded Leopard</item>
	<item>Clown Fish</item>
	<item>Clumber Spaniel</item>
	<item>Coati</item>
	<item>Cockroach</item>
	<item>Collared Peccary</item>
	<item>Collie</item>
	<item>Common Buzzard</item>
	<item>Common Frog</item>
	<item>Common Loon</item>
	<item>Common Toad</item>
	<item>Coral</item>
	<item>Cottontop Tamarin</item>
	<item>Cougar</item>
	<item>Cow</item>
	<item>Coyote</item>
	<item>Crab</item>
	<item>Crab-Eating Macaque</item>
	<item>Crane</item>
	<item>Crested Penguin</item>
	<item>Crocodile</item>
	<item>Cross River Gorilla</item>
	<item>Curly Coated Retriever</item>
	<item>Cuscus</item>
	<item>Cuttlefish</item>
	<item>Dachshund</item>
	<item>Dalmatian</item>
	<item>Darwin\'s Frog</item>
	<item>Deer</item>
	<item>Desert Tortoise</item>
	<item>Deutsche Bracke</item>
	<item>Dhole</item>
	<item>Dingo</item>
	<item>Discus</item>
	<item>Doberman Pinscher</item>
	<item>Dodo</item>
	<item>Dog</item>
	<item>Dogo Argentino</item>
	<item>Dogue De Bordeaux</item>
	<item>Dolphin</item>
	<item>Donkey</item>
	<item>Dormouse</item>
	<item>Dragonfly</item>
	<item>Drever</item>
	<item>Duck</item>
	<item>Dugong</item>
	<item>Dunker</item>
	<item>Dusky Dolphin</item>
	<item>Dwarf Crocodile</item>
	<item>Eagle</item>
	<item>Earwig</item>
	<item>Eastern Gorilla</item>
	<item>Eastern Lowland Gorilla</item>
	<item>Echidna</item>
	<item>Edible Frog</item>
	<item>Egyptian Mau</item>
	<item>Electric Eel</item>
	<item>Elephant</item>
	<item>Elephant Seal</item>
	<item>Elephant Shrew</item>
	<item>Emperor Penguin</item>
	<item>Emperor Tamarin</item>
	<item>Emu</item>
	<item>English Cocker Spaniel</item>
	<item>English Shepherd</item>
	<item>English Springer Spaniel</item>
	<item>Entlebucher Mountain Dog</item>
	<item>Epagneul Pont Audemer</item>
	<item>Eskimo Dog</item>
	<item>Estrela Mountain Dog</item>
	<item>Falcon</item>
	<item>Fennec Fox</item>
	<item>Ferret</item>
	<item>Field Spaniel</item>
	<item>Fin Whale</item>
	<item>Finnish Spitz</item>
	<item>Fire-Bellied Toad</item>
	<item>Fish</item>
	<item>Fishing Cat</item>
	<item>Flamingo</item>
	<item>Flat Coat Retriever</item>
	<item>Flounder</item>
	<item>Fly</item>
	<item>Flying Squirrel</item>
	<item>Fossa</item>
	<item>Fox</item>
	<item>Fox Terrier</item>
	<item>French Bulldog</item>
	<item>Frigatebird</item>
	<item>Frilled Lizard</item>
	<item>Frog</item>
	<item>Fur Seal</item>
	<item>Galapagos Penguin</item>
	<item>Galapagos Tortoise</item>
	<item>Gar</item>
	<item>Gecko</item>
	<item>Gentoo Penguin</item>
	<item>Geoffroys Tamarin</item>
	<item>Gerbil</item>
	<item>German Pinscher</item>
	<item>German Shepherd</item>
	<item>Gharial</item>
	<item>Giant African Land Snail</item>
	<item>Giant Clam</item>
	<item>Giant Panda Bear</item>
	<item>Giant Schnauzer</item>
	<item>Gibbon</item>
	<item>Gila Monster</item>
	<item>Giraffe</item>
	<item>Glass Lizard</item>
	<item>Glow Worm</item>
	<item>Goat</item>
	<item>Golden Lion Tamarin</item>
	<item>Golden Oriole</item>
	<item>Golden Retriever</item>
	<item>Goose</item>
	<item>Gopher</item>
	<item>Gorilla</item>
	<item>Grasshopper</item>
	<item>Great Dane</item>
	<item>Great White Shark</item>
	<item>Greater Swiss Mountain Dog</item>
	<item>Green Bee-Eater</item>
	<item>Greenland Dog</item>
	<item>Grey Mouse Lemur</item>
	<item>Grey Reef Shark</item>
	<item>Grey Seal</item>
	<item>Greyhound</item>
	<item>Grizzly Bear</item>
	<item>Grouse</item>
	<item>Guinea Fowl</item>
	<item>Guinea Pig</item>
	<item>Guppy</item>
	<item>Hammerhead Shark</item>
	<item>Hamster</item>
	<item>Hare</item>
	<item>Harrier</item>
	<item>Havanese</item>
	<item>Hedgehog</item>
	<item>Hercules Beetle</item>
	<item>Hermit Crab</item>
	<item>Heron</item>
	<item>Highland Cattle</item>
	<item>Himalayan</item>
	<item>Hippopotamus</item>
	<item>Honey Bee</item>
	<item>Horn Shark</item>
	<item>Horned Frog</item>
	<item>Horse</item>
	<item>Horseshoe Crab</item>
	<item>Howler Monkey</item>
	<item>Human</item>
	<item>Humboldt Penguin</item>
	<item>Hummingbird</item>
	<item>Humpback Whale</item>
	<item>Hyena</item>
	<item>Ibis</item>
	<item>Ibizan Hound</item>
	<item>Iguana</item>
	<item>Impala</item>
	<item>Indian Elephant</item>
	<item>Indian Palm Squirrel</item>
	<item>Indian Rhinoceros</item>
	<item>Indian Star Tortoise</item>
	<item>Indochinese Tiger</item>
	<item>Indri</item>
	<item>Insect</item>
	<item>Irish Setter</item>
	<item>Irish WolfHound</item>
	<item>Jack Russel</item>
	<item>Jackal</item>
	<item>Jaguar</item>
	<item>Japanese Chin</item>
	<item>Japanese Macaque</item>
	<item>Javan Rhinoceros</item>
	<item>Javanese</item>
	<item>Jellyfish</item>
	<item>Kakapo</item>
	<item>Kangaroo</item>
	<item>Keel Billed Toucan</item>
	<item>Killer Whale</item>
	<item>King Crab</item>
	<item>King Penguin</item>
	<item>Kingfisher</item>
	<item>Kiwi</item>
	<item>Koala</item>
	<item>Komodo Dragon</item>
	<item>Kudu</item>
	<item>Labradoodle</item>
	<item>Labrador Retriever</item>
	<item>Ladybird</item>
	<item>Leaf-Tailed Gecko</item>
	<item>Lemming</item>
	<item>Lemur</item>
	<item>Leopard</item>
	<item>Leopard Cat</item>
	<item>Leopard Seal</item>
	<item>Leopard Tortoise</item>
	<item>Liger</item>
	<item>Lion</item>
	<item>Lionfish</item>
	<item>Little Penguin</item>
	<item>Lizard</item>
	<item>Llama</item>
	<item>Lobster</item>
	<item>Long-Eared Owl</item>
	<item>Lynx</item>
	<item>Macaroni Penguin</item>
	<item>Macaw</item>
	<item>Magellanic Penguin</item>
	<item>Magpie</item>
	<item>Maine Coon</item>
	<item>Malayan Civet</item>
	<item>Malayan Tiger</item>
	<item>Maltese</item>
	<item>Manatee</item>
	<item>Mandrill</item>
	<item>Manta Ray</item>
	<item>Marine Toad</item>
	<item>Markhor</item>
	<item>Marsh Frog</item>
	<item>Masked Palm Civet</item>
	<item>Mastiff</item>
	<item>Mayfly</item>
	<item>Meerkat</item>
	<item>Millipede</item>
	<item>Minke Whale</item>
	<item>Mole</item>
	<item>Molly</item>
	<item>Mongoose</item>
	<item>Mongrel</item>
	<item>Monitor Lizard</item>
	<item>Monkey</item>
	<item>Monte Iberia Eleuth</item>
	<item>Moorhen</item>
	<item>Moose</item>
	<item>Moray Eel</item>
	<item>Moth</item>
	<item>Mountain Gorilla</item>
	<item>Mountain Lion</item>
	<item>Mouse</item>
	<item>Mule</item>
	<item>Neanderthal</item>
	<item>Neapolitan Mastiff</item>
	<item>Newfoundland</item>
	<item>Newt</item>
	<item>Nightingale</item>
	<item>Norfolk Terrier</item>
	<item>Norwegian Forest</item>
	<item>Numbat</item>
	<item>Nurse Shark</item>
	<item>Ocelot</item>
	<item>Octopus</item>
	<item>Okapi</item>
	<item>Old English Sheepdog</item>
	<item>Olm</item>
	<item>Opossum</item>
	<item>Orang-utan</item>
	<item>Ostrich</item>
	<item>Otter</item>
	<item>Oyster</item>
	<item>Pademelon</item>
	<item>Panther</item>
	<item>Parrot</item>
	<item>Patas Monkey</item>
	<item>Peacock</item>
	<item>Pekingese</item>
	<item>Pelican</item>
	<item>Penguin</item>
	<item>Persian</item>
	<item>Pheasant</item>
	<item>Pied Tamarin</item>
	<item>Pig</item>
	<item>Pika</item>
	<item>Pike</item>
	<item>Pink Fairy Armadillo</item>
	<item>Piranha</item>
	<item>Platypus</item>
	<item>Pointer</item>
	<item>Poison Dart Frog</item>
	<item>Polar Bear</item>
	<item>Pond Skater</item>
	<item>Poodle</item>
	<item>Pool Frog</item>
	<item>Porcupine</item>
	<item>Possum</item>
	<item>Prawn</item>
	<item>Proboscis Monkey</item>
	<item>Puffer Fish</item>
	<item>Puffin</item>
	<item>Pug</item>
	<item>Puma</item>
	<item>Purple Emperor</item>
	<item>Puss Moth</item>
	<item>Pygmy Hippopotamus</item>
	<item>Pygmy Marmoset</item>
	<item>Quail</item>
	<item>Quetzal</item>
	<item>Quokka</item>
	<item>Quoll</item>
	<item>Rabbit</item>
	<item>Raccoon</item>
	<item>Raccoon Dog</item>
	<item>Radiated Tortoise</item>
	<item>Ragdoll</item>
	<item>Rat</item>
	<item>Rattlesnake</item>
	<item>Red Knee Tarantula</item>
	<item>Red Panda</item>
	<item>Red Wolf</item>
	<item>Red-handed Tamarin</item>
	<item>Reindeer</item>
	<item>Rhinoceros</item>
	<item>River Dolphin</item>
	<item>River Turtle</item>
	<item>Robin</item>
	<item>Rock Hyrax</item>
	<item>Rockhopper Penguin</item>
	<item>Roseate Spoonbill</item>
	<item>Rottweiler</item>
	<item>Royal Penguin</item>
	<item>Russian Blue</item>
	<item>Sabre-Toothed Tiger</item>
	<item>Saint Bernard</item>
	<item>Salamander</item>
	<item>Sand Lizard</item>
	<item>Saola</item>
	<item>Scorpion</item>
	<item>Scorpion Fish</item>
	<item>Sea Dragon</item>
	<item>Sea Lion</item>
	<item>Sea Otter</item>
	<item>Sea Slug</item>
	<item>Sea Squirt</item>
	<item>Sea Turtle</item>
	<item>Sea Urchin</item>
	<item>Seahorse</item>
	<item>Seal</item>
	<item>Serval</item>
	<item>Sheep</item>
	<item>Shih Tzu</item>
	<item>Shrimp</item>
	<item>Siamese</item>
	<item>Siamese Fighting Fish</item>
	<item>Siberian</item>
	<item>Siberian Husky</item>
	<item>Siberian Tiger</item>
	<item>Silver Dollar</item>
	<item>Skunk</item>
	<item>Sloth</item>
	<item>Slow Worm</item>
	<item>Snail</item>
	<item>Snake</item>
	<item>Snapping Turtle</item>
	<item>Snowshoe</item>
	<item>Snowy Owl</item>
	<item>Somali</item>
	<item>South China Tiger</item>
	<item>Spadefoot Toad</item>
	<item>Sparrow</item>
	<item>Spectacled Bear</item>
	<item>Sperm Whale</item>
	<item>Spider Monkey</item>
	<item>Spiny Dogfish</item>
	<item>Sponge</item>
	<item>Squid</item>
	<item>Squirrel</item>
	<item>Squirrel Monkey</item>
	<item>Sri Lankan Elephant</item>
	<item>Staffordshire Bull Terrier</item>
	<item>Stag Beetle</item>
	<item>Starfish</item>
	<item>Stellers Sea Cow</item>
	<item>Stick Insect</item>
	<item>Stingray</item>
	<item>Stoat</item>
	<item>Striped Rocket Frog</item>
	<item>Sumatran Elephant</item>
	<item>Sumatran Orang-utan</item>
	<item>Sumatran Rhinoceros</item>
	<item>Sumatran Tiger</item>
	<item>Sun Bear</item>
	<item>Swan</item>
	<item>Tang</item>
	<item>Tapir</item>
	<item>Tarsier</item>
	<item>Tasmanian Devil</item>
	<item>Tawny Owl</item>
	<item>Termite</item>
	<item>Tetra</item>
	<item>Thorny Devil</item>
	<item>Tibetan Mastiff</item>
	<item>Tiffany</item>
	<item>Tiger</item>
	<item>Tiger Salamander</item>
	<item>Tiger Shark</item>
	<item>Tortoise</item>
	<item>Toucan</item>
	<item>Tree Frog</item>
	<item>Tropicbird</item>
	<item>Tuatara</item>
	<item>Turkey</item>
	<item>Turkish Angora</item>
	<item>Uakari</item>
	<item>Uguisu</item>
	<item>Umbrellabird</item>
	<item>Vampire Bat</item>
	<item>Vervet Monkey</item>
	<item>Vulture</item>
	<item>Wallaby</item>
	<item>Walrus</item>
	<item>Warthog</item>
	<item>Wasp</item>
	<item>Water Buffalo</item>
	<item>Water Dragon</item>
	<item>Water Vole</item>
	<item>Weasel</item>
	<item>Welsh Corgi</item>
	<item>West Highland Terrier</item>
	<item>Western Gorilla</item>
	<item>Western Lowland Gorilla</item>
	<item>Whale Shark</item>
	<item>Whippet</item>
	<item>White Faced Capuchin</item>
	<item>White Rhinoceros</item>
	<item>White Tiger</item>
	<item>Wild Boar</item>
	<item>Wildebeest</item>
	<item>Wolf</item>
	<item>Wolverine</item>
	<item>Wombat</item>
	<item>Woodlouse</item>
	<item>Woodpecker</item>
	<item>Woolly Mammoth</item>
	<item>Woolly Monkey</item>
	<item>Wrasse</item>
	<item>X-Ray Tetra</item>
	<item>Yak</item>
	<item>Yellow-Eyed Penguin</item>
	<item>Yorkshire Terrier</item>
	<item>Zebra</item>
	<item>Zebra Shark</item>
	<item>Zebu</item>
	<item>Zonkey</item>
	<item>Zorse</item>
	</string-array>
	</resources>

view raw arrays.xml hosted with ❤ by GitHub

	<?xml version="1.0" encoding="utf-8"?>
	<resources>
	<dimen name="header">30dp</dimen>
	</resources>

view raw dimens.xml hosted with ❤ by GitHub

	import android.os.Bundle;
	import android.support.v7.app.AppCompatActivity;
	import android.support.v7.widget.LinearLayoutManager;
	import android.support.v7.widget.RecyclerView;
	import java.util.ArrayList;
	import java.util.Arrays;
	import java.util.List;
	public class MainActivity extends AppCompatActivity {
	private RecyclerView mRecyclerView;
	private Adapter adapter;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
	super.onCreate(savedInstanceState);
	setContentView(R.layout.activity_main);
	mRecyclerView = (RecyclerView) findViewById(R.id.recyclerview);
	mRecyclerView.setLayoutManager(new LinearLayoutManager(this));
	adapter = new Adapter(this,getData());
	mRecyclerView.setAdapter(adapter);
	RecyclerSectionItemDecoration sectionItemDecoration =
	new RecyclerSectionItemDecoration(getResources().getDimensionPixelSize(R.dimen.header),
	true,
	getSectionCallback(getData()));
	mRecyclerView.addItemDecoration(sectionItemDecoration);
	}
	public ArrayList<String> getData() {
	String[] strings = getResources().getStringArray(R.array.animals);
	ArrayList<String> list = new ArrayList<String>(Arrays.asList(strings));
	return list;
	}
	private RecyclerSectionItemDecoration.SectionCallback getSectionCallback(final List<String> people) {
	return new RecyclerSectionItemDecoration.SectionCallback() {
	@Override
	public boolean isSection(int position) {
	return position == 0
	|| people.get(position)
	.charAt(0) != people.get(position - 1)
	.charAt(0);
	}
	@Override
	public CharSequence getSectionHeader(int position) {
	return people.get(position)
	.subSequence(0,
	1);
	}
	};
	}
	}

view raw MainActivity.java hosted with ❤ by GitHub

	import android.graphics.Canvas;
	import android.graphics.Rect;
	import android.support.annotation.NonNull;
	import android.support.v7.widget.RecyclerView;
	import android.view.LayoutInflater;
	import android.view.View;
	import android.view.ViewGroup;
	import android.widget.TextView;
	public class RecyclerSectionItemDecoration extends RecyclerView.ItemDecoration {
	private final int headerOffset;
	private final boolean sticky;
	private final SectionCallback sectionCallback;
	private View headerView;
	private TextView header;
	public RecyclerSectionItemDecoration(int headerHeight, boolean sticky, @NonNull SectionCallback sectionCallback) {
	headerOffset = headerHeight;
	this.sticky = sticky;
	this.sectionCallback = sectionCallback;
	}
	@Override
	public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
	super.getItemOffsets(outRect, view, parent, state);
	int pos = parent.getChildAdapterPosition(view);
	if (sectionCallback.isSection(pos)) {
	outRect.top = headerOffset;
	}
	}
	@Override
	public void onDrawOver(Canvas c, RecyclerView parent, RecyclerView.State state) {
	super.onDrawOver(c, parent, state);
	if (headerView == null) {
	headerView = inflateHeaderView(parent);
	header = (TextView) headerView.findViewById(R.id.tv_header);
	fixLayoutSize(headerView, parent);
	}
	CharSequence previousHeader = "";
	for (int i = 0; i < parent.getChildCount(); i++) {
	View child = parent.getChildAt(i);
	final int position = parent.getChildAdapterPosition(child);
	CharSequence title = sectionCallback.getSectionHeader(position);
	header.setText(title);
	if (!previousHeader.equals(title) || sectionCallback.isSection(position)) {
	drawHeader(c, child, headerView);
	previousHeader = title;
	}
	}
	}
	private void drawHeader(Canvas c, View child, View headerView) {
	c.save();
	if (sticky) {
	c.translate(0, Math.max(0, child.getTop() - headerView.getHeight()));
	} else {
	c.translate(0, child.getTop() - headerView.getHeight());
	}
	headerView.draw(c);
	c.restore();
	}
	private View inflateHeaderView(RecyclerView parent) {
	return LayoutInflater.from(parent.getContext())
	.inflate(R.layout.view_header, parent, false);
	}
	private void fixLayoutSize(View view, ViewGroup parent) {
	int widthSpec = View.MeasureSpec.makeMeasureSpec(parent.getWidth(),
	View.MeasureSpec.EXACTLY);
	int heightSpec = View.MeasureSpec.makeMeasureSpec(parent.getHeight(),
	View.MeasureSpec.UNSPECIFIED);
	int childWidth = ViewGroup.getChildMeasureSpec(widthSpec,
	parent.getPaddingLeft() + parent.getPaddingRight(),
	view.getLayoutParams().width);
	int childHeight = ViewGroup.getChildMeasureSpec(heightSpec,
	parent.getPaddingTop() + parent.getPaddingBottom(),
	view.getLayoutParams().height);
	view.measure(childWidth, childHeight);
	view.layout(0, 0, view.getMeasuredWidth(), view.getMeasuredHeight());
	}
	public interface SectionCallback {
	boolean isSection(int position);
	CharSequence getSectionHeader(int position);
	}
	}

view raw RecyclerSectionItemDecoration.java hosted with ❤ by GitHub

	<?xml version="1.0" encoding="utf-8"?>
	<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
	android:layout_width="match_parent"
	android:layout_height="wrap_content"
	android:background="@color/colorPrimary">
	<TextView
	android:id="@+id/tv_header"
	android:layout_width="match_parent"
	android:layout_height="wrap_content"
	android:clickable="true"
	android:orientation="horizontal"
	android:padding="10dp"
	android:text="Hardik Lakhani"
	android:textColor="@android:color/white"
	android:textSize="14sp" />
	</LinearLayout>

view raw view_header.xml hosted with ❤ by GitHub

	<?xml version="1.0" encoding="utf-8"?>
	<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
	android:layout_width="match_parent"
	android:layout_height="wrap_content"
	android:background="@color/colorAccent">
	<TextView
	android:id="@+id/tv_item"
	android:layout_width="match_parent"
	android:layout_height="wrap_content"
	android:clickable="true"
	android:orientation="horizontal"
	android:padding="10dp"
	android:text="Hardik Lakhani"
	android:textColor="@android:color/white"
	android:textSize="14sp" />
	</LinearLayout>

view raw view_item.xml hosted with ❤ by GitHub

> Here arrays.xml contains some dummy names so we can show up a demo.

> Run this application and see the sticky header in your screen.

> You can see the output in following video