Rocket.Chat.ReactNative/app/containers/Sidebar.js

import React, { Component } from 'react';
import PropTypes from 'prop-types';
import { ScrollView, Text, View, StyleSheet, FlatList, TouchableHighlight } from 'react-native';
import { DrawerItems } from 'react-navigation';
import { connect } from 'react-redux';

import realm from '../lib/realm';
import { setServer } from '../actions/server';

const styles = StyleSheet.create({
	scrollView: {
		paddingTop: 20
	},
	imageContainer: {
		width: '100%',
		alignItems: 'center'
	},
	image: {
		width: 200,
		height: 200,
		borderRadius: 100
	},
	serverTitle: {
		fontSize: 16,
		color: 'grey',
		padding: 10,
		width: '100%'
	},
	serverItem: {
		backgroundColor: 'white',
		padding: 10,
		flex: 1
	},
	selectedServer: {
		backgroundColor: '#eeeeee'
	}
});

@connect(state => ({
	server: state.server.server
}), dispatch => ({
	selectServer: server => dispatch(setServer(server))
}))
export default class Sidebar extends Component {
	static propTypes = {
		server: PropTypes.string.isRequired,
		selectServer: PropTypes.func.isRequired,
		navigation: PropTypes.object.isRequired
	}

	componentWillMount() {
		realm.addListener('change', this.updateState);
		this.state = this.getState();
	}

	componentWillUnmount() {
		realm.removeListener('change', this.updateState);
	}

	onItemPress = ({ route, focused }) => {
		this.props.navigation.navigate('DrawerClose');
		if (!focused) {
			this.props.navigation.navigate(route.routeName, undefined);
		}
	}

	onPressItem = (item) => {
		this.props.selectServer(item.id);
		this.props.navigation.navigate('DrawerClose');
	}

	getState = () => ({
		servers: realm.objects('servers')
	})

	updateState = () => {
		this.setState(this.getState());
	}

	renderItem = ({ item, separators }) => (

		<TouchableHighlight
			onShowUnderlay={separators.highlight}
			onHideUnderlay={separators.unhighlight}
			onPress={() => { this.onPressItem(item); }}
		>
			<View style={[styles.serverItem, (item.id === this.props.server ? styles.selectedServer : null)]}>
				<Text>
					{item.id}
				</Text>
			</View>
		</TouchableHighlight>
	);

	render() {
		return (
			<ScrollView style={styles.scrollView}>
				<View style={{ paddingBottom: 20 }}>
					<DrawerItems
						{...this.props}
						onItemPress={this.onItemPress}
					/>

					<Text style={styles.serverTitle}>SERVERS</Text>
					<FlatList
						data={this.state.servers}
						renderItem={this.renderItem}
						keyExtractor={item => item.id}
					/>
				</View>
			</ScrollView>
		);
	}
}