List of contacts through cursor loader framework

Loaders work on a separate thread so your app carries on working while the Loader gets the data. Loaders monitor the data source for any changes and updates the data it gives you. Loaders take care of restoring the cursor after a configuration change without having to do a re-query

Here is the code snippet for the same.You can download the source code from github

	package com.roy.multiselect;
	import android.database.Cursor;
	import android.database.MatrixCursor;
	import android.os.Bundle;
	import android.provider.ContactsContract;
	import android.support.design.widget.FloatingActionButton;
	import android.support.design.widget.Snackbar;
	import android.support.v4.app.LoaderManager;
	import android.support.v4.content.CursorLoader;
	import android.support.v4.content.Loader;
	import android.support.v7.widget.LinearLayoutManager;
	import android.support.v7.widget.RecyclerView;
	import android.view.View;
	import android.support.design.widget.NavigationView;
	import android.support.v4.view.GravityCompat;
	import android.support.v4.widget.DrawerLayout;
	import android.support.v7.app.ActionBarDrawerToggle;
	import android.support.v7.app.AppCompatActivity;
	import android.support.v7.widget.Toolbar;
	import android.view.Menu;
	import android.view.MenuItem;
	import com.roy.adapter.ContactAdapter;
	import butterknife.Bind;
	import butterknife.ButterKnife;
	public class MainActivity extends AppCompatActivity
	implements NavigationView.OnNavigationItemSelectedListener,LoaderManager.LoaderCallbacks<Cursor> {
	ContactAdapter adapter;
	@Bind(R.id.recyclerview)
	RecyclerView recyclerView;
	private static final int LOADER_SEARCH_RESULTS = 1;
	String[] projectionFields;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
	super.onCreate(savedInstanceState);
	setContentView(R.layout.activity_main);
	ButterKnife.bind(this);
	Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
	setSupportActionBar(toolbar);
	FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
	fab.setOnClickListener(new View.OnClickListener() {
	@Override
	public void onClick(View view) {
	Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
	.setAction("Action", null).show();
	}
	});
	DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
	ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
	this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
	drawer.setDrawerListener(toggle);
	toggle.syncState();
	NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
	navigationView.setNavigationItemSelectedListener(this);
	LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this);
	recyclerView.setLayoutManager(linearLayoutManager);
	getSupportLoaderManager().initLoader(LOADER_SEARCH_RESULTS, null, this);
	}
	@Override
	public void onBackPressed() {
	DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
	if (drawer.isDrawerOpen(GravityCompat.START)) {
	drawer.closeDrawer(GravityCompat.START);
	} else {
	super.onBackPressed();
	}
	}
	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
	// Inflate the menu; this adds items to the action bar if it is present.
	getMenuInflater().inflate(R.menu.main, menu);
	return true;
	}
	@Override
	public boolean onOptionsItemSelected(MenuItem item) {
	// Handle action bar item clicks here. The action bar will
	// automatically handle clicks on the Home/Up button, so long
	// as you specify a parent activity in AndroidManifest.xml.
	int id = item.getItemId();
	//noinspection SimplifiableIfStatement
	if (id == R.id.action_settings) {
	return true;
	}
	return super.onOptionsItemSelected(item);
	}
	@SuppressWarnings("StatementWithEmptyBody")
	@Override
	public boolean onNavigationItemSelected(MenuItem item) {
	// Handle navigation view item clicks here.
	int id = item.getItemId();
	if (id == R.id.nav_camera) {
	// Handle the camera action
	} else if (id == R.id.nav_gallery) {
	} else if (id == R.id.nav_slideshow) {
	} else if (id == R.id.nav_manage) {
	} else if (id == R.id.nav_share) {
	} else if (id == R.id.nav_send) {
	}
	DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
	drawer.closeDrawer(GravityCompat.START);
	return true;
	}
	@Override
	public Loader<Cursor> onCreateLoader(int id, Bundle args) {
	switch (id) {
	case LOADER_SEARCH_RESULTS:
	projectionFields = new String[]{
	ContactsContract.Contacts._ID,
	ContactsContract.Contacts.DISPLAY_NAME,
	ContactsContract.Contacts.HAS_PHONE_NUMBER,
	ContactsContract.CommonDataKinds.Phone.NUMBER,
	ContactsContract.CommonDataKinds.Phone.PHOTO_URI,
	ContactsContract.Data.LOOKUP_KEY
	};
	final String whereClause = ContactsContract.Contacts.HAS_PHONE_NUMBER + "='1'";
	final String sortOrder = ContactsContract.Contacts.DISPLAY_NAME + " ASC";
	// Construct the loader
	CursorLoader cursorLoader = new CursorLoader(this,
	ContactsContract.CommonDataKinds.Phone.CONTENT_URI, // URI
	projectionFields, // projection fields
	whereClause, // the selection criteria
	null, // the selection args
	sortOrder // the sort order
	);
	// Return the loader for use
	return cursorLoader;
	}
	return null;
	}
	@Override
	public void onLoaderReset(Loader<Cursor> loader) {
	switch (loader.getId())
	{
	case LOADER_SEARCH_RESULTS:
	adapter.swapCursor(null);
	break;
	}
	}
	@Override
	public void onLoadFinished(Loader<Cursor> loader, Cursor cursor) {
	switch (loader.getId())
	{
	case LOADER_SEARCH_RESULTS:
	MatrixCursor newCursor = new MatrixCursor(projectionFields); // Same projection used in loader
	if ( cursor!=null && cursor.moveToFirst()) {
	String lastName = "";
	do {
	if (cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME)).compareToIgnoreCase(lastName) != 0) {
	newCursor.addRow(new Object[]{cursor.getString(0), cursor.getString(1), cursor.getString(2),cursor.getString(3),cursor.getString(4),cursor.getString(5)}); // match the original cursor fields
	lastName =cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME));
	}
	} while (cursor.moveToNext());
	}
	if(newCursor!=null) {
	adapter = new ContactAdapter(this, newCursor);
	adapter.swapCursor(newCursor);
	recyclerView.setAdapter(adapter);
	}
	break;
	}
	}
	}

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