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· 20 min read

Building a Chat App with React Native and Gifted Chat (Part 4)

In this tutorial series, I'll be showing you how to build a functional and secure chat app using the latest React Native libraries, including Gifted Chat and the Expo framework, powered by the ChatKitty platform.

So far you learned how to use the Gifted Chat React Native library with ChatKitty's JavaScript SDK to build a full-featured chat screen with real-time messaging functionality into your app, adding screens for users to create public channels, discover new channels, and view their channels. In the third article of this series, you enhanced that chat experience by implementing in-app and push notifications to notify your users when chat events occur.

In this tutorial, you'll be building on the group chat experience you created adding direct messaging to allow users to communicate privately. You'll also be adding a few enhancements to the chat experience including typing indicators, and chat room presence notifications.

After reading this article, you will be able to:

  1. Create direct channels for users to chat privately

  2. Integrate Gifted Chat's in-built typing indicator and implement a custom more detailed indicator

  3. Notify chat users when a user enters or leaves the chat from a chat screen

  4. Allow users to leave chat channels they are no longer interested in

If you followed along the previous articles, you should already have the ChatKitty JavaScript SDK NPM package added to your Expo React Native project.


Before we begin, let's go over some terms we'll be using a lot in this article.

Direct channels​

Previously, we learned about ChatKitty chat channels, specifically public channels that users can discover and join, or be invited to join. Direct channels, on the other hand, let users have private conversations between up to 9 other users. New users cannot be added to a direct channel and there can only exist one direct channel between a set of users. Direct channels are perfect for one-off conversations that don't require an entire channel to discuss.

Entering a chat​

When a user starts a chat session and has no other active chat sessions in the session channel, the user has entered a chat. In other words, users who have entered a chat have at least one active chat session for that chat channel, and are active participants of the conversation. Active chat participants receive real-time messaging events, and are present to reply immediately.

Leaving a chat​

After a user ends a chat session and has no other active chat sessions in the session channel, the user has left a chat. Users leave a chat when there is no longer at least one active chat session for that chat channel, and are no longer active participants of the conversation. After leaving a chat, users begin to get notifications of events that happened in the chat while they are away.

Leaving a channel​

After a user joins a channel, the user becomes a channel member. Channel members can send messages in a channel, and receives messages and notifications related to the channel. If a user is no longer interested in a channel, the user can leave the channel and is no longer a channel member.

Okay, let's get started! 🏎️

Next, you'll be adding direct messaging functionality to your chat app.

Creating a direct messaging channel​

Edit the chatScreen.js screen file you previous created to destructure its navigation prop:

export default function ChatScreen({ route, navigation /* Add this */ }) {
  const { user } = useContext(AuthContext);
  const { channel } = route.params;

  // Unchanged
}

Now, you can customize your Gifted Chat message avatar to create or get a direct channel, and navigate the user to a new chat screen with the direct channel when it's pressed.

Define a new method renderAvatar to pass into your GiftedChat component:

import { Avatar, Bubble, GiftedChat } from 'react-native-gifted-chat';

// Unchanged

function renderAvatar(props) {
  return (
    <Avatar
      {...props}
      onPressAvatar={(avatarUser) => {
        chatkitty
          .createChannel({
            type: 'DIRECT',
            members: [{ id: avatarUser._id }]
          })
          .then((result) => {
            navigation.navigate('Chat', { channel: result.channel });
          });
      }}
    />
  );
}

Set the GiftedChat renderAvatar prop to the method you defined:

return (
  <GiftedChat
    messages={messages}
    onSend={handleSend}
    user={mapUser(user)}
    loadEarlier={loadEarlier}
    isLoadingEarlier={isLoadingEarlier}
    onLoadEarlier={handleLoadEarlier}
    renderBubble={renderBubble}
    renderAvatar={renderAvatar} /* Add this */
  />
);

After these changes, chatScreen.js should look like this:

import React, { useContext, useEffect, useState } from 'react';
import { Avatar, Bubble, GiftedChat } from 'react-native-gifted-chat';

import { chatkitty } from '../chatkitty';
import Loading from '../components/loading';
import { AuthContext } from '../context/authProvider';

export default function ChatScreen({ route, navigation }) {
  const { user } = useContext(AuthContext);
  const { channel } = route.params;

  const [messages, setMessages] = useState([]);
  const [loading, setLoading] = useState(true);
  const [loadEarlier, setLoadEarlier] = useState(false);
  const [isLoadingEarlier, setIsLoadingEarlier] = useState(false);
  const [messagePaginator, setMessagePaginator] = useState(null);

  useEffect(() => {
    const startChatSessionResult = chatkitty.startChatSession({
      channel: channel,
      onMessageReceived: (message) => {
        setMessages((currentMessages) =>
          GiftedChat.append(currentMessages, [mapMessage(message)])
        );
      }
    });

    chatkitty
      .listMessages({
        channel: channel
      })
      .then((result) => {
        setMessages(result.paginator.items.map(mapMessage));

        setMessagePaginator(result.paginator);
        setLoadEarlier(result.paginator.hasNextPage);

        setLoading(false);
      });

    return startChatSessionResult.session.end;
  }, [user, channel]);

  async function handleSend(pendingMessages) {
    await chatkitty.sendMessage({
      channel: channel,
      body: pendingMessages[0].text
    });
  };

  async function handleLoadEarlier() {
    if (!messagePaginator.hasNextPage) {
      setLoadEarlier(false);

      return;
    }

    setIsLoadingEarlier(true);

    const nextPaginator = await messagePaginator.nextPage();

    setMessagePaginator(nextPaginator);

    setMessages((currentMessages) =>
      GiftedChat.prepend(currentMessages, nextPaginator.items.map(mapMessage))
    );

    setIsLoadingEarlier(false);
  }

  function renderBubble(props) {
    return (
      <Bubble
        {...props}
        wrapperStyle={{
          left: {
            backgroundColor: '#d3d3d3'
          }
        }}
      />
    );
  }

  function renderAvatar(props) {
    return (
      <Avatar
        {...props}
        onPressAvatar={(avatarUser) => {
          chatkitty
            .createChannel({
              type: 'DIRECT',
              members: [{ id: avatarUser._id }]
            })
            .then((result) => {
              navigation.navigate('Chat', { channel: result.channel });
            });
        }}
      />
    );
  }

  if (loading) {
    return <Loading />;
  }

  return (
    <GiftedChat
      messages={messages}
      onSend={handleSend}
      user={mapUser(user)}
      loadEarlier={loadEarlier}
      isLoadingEarlier={isLoadingEarlier}
      onLoadEarlier={handleLoadEarlier}
      renderBubble={renderBubble}
      renderAvatar={renderAvatar}
    />
  );
}

function mapMessage(message) {
  return {
    _id: message.id,
    text: message.body,
    createdAt: new Date(message.createdTime),
    user: mapUser(message.user)
  };
}

function mapUser(user) {
  return {
    _id: user.id,
    name: user.displayName,
    avatar: user.displayPictureUrl
  };
}

If you run the app now and go to a public chat screen, you should see:

Screenshot: Public chat

Tapping a message avatar should take you to a new chat screen where you can have a direct private conversation.

ChatKitty doesn't expose unique names for direct channels, so we don't see a channel name in the app title bar. Let's create an appropriate name for the chat screen title.

Add a helper method channelDisplayName to the index.js file in the src/chatkitty/ directory:

export function channelDisplayName(channel) {
  if (channel.type === 'DIRECT') {
    return channel.members.map((member) => member.displayName).join(', ');
  } else {
    return channel.name;
  }
}

After this change, index.js should look like this:

import ChatKitty from '@chatkitty/core';

export const chatkitty = ChatKitty.getInstance('YOUR CHATKITTY API KEY HERE');

export function channelDisplayName(channel) {
  if (channel.type === 'DIRECT') {
    return channel.members.map((member) => member.displayName).join(', ');
  } else {
    return channel.name;
  }
}

You can now update your app to use a more readable channel display name.

Update homeStack.js in src/context to use the channelDisplayName method:

import { chatkitty, channelDisplayName } from '../chatkitty';

// Unchanged

<ChatStack.Screen
  name='Chat'
  component={ChatScreen}
  options={({ route }) => ({
    title: channelDisplayName(route.params.channel) /* Add this */
  })}
/>;

Also update browseChannelsScreen.js and homeScreen.js in src/screens to use the helper method:

import { chatkitty, channelDisplayName } from '../chatkitty';

// Unchanged

<List.Item
  title={channelDisplayName(item)} /* Add this */
  // Unchanged
/>;

Running the app now shows the display names of a direct channel's members in the title bar

Screenshot: Direct chat name

Great! Now you can privately chat with other channel members. Now let's move on to enhancing your chat app's experience with a typing indicator.

Adding a typing indicator with Gifted Chat and ChatKitty​

The Gifted Chat React Native library saves you a lot of time when creating a chat UI. By providing a bunch of component props, you can customize the chat UI and implement chat features like typing indicators, using a chat service like ChatKitty.

You'll be using the isTyping Gifted Chat prop to display a typing indicator when another user is typing.

Screenshot: Simple typing indicator partial

ChatKitty tracks the typing state of users sending typing keystrokes in a channel. You'll need to send typing keystrokes to ChatKitty to let it know when a user is typing. When starting a chat session, you can register handler methods with ChatKitty to handle chat events like when a user starts or stops typing, enters or leaves a chat, enters keystrokes, etc. You can track when a user starts and stops typing with ChatKitty handler methods, storing the current user typing in your component state. Using the typing user state, you can set Gifted Chat's isTyping prop to display the typing indicator.

Add a helper method handleInputTextChanged in chatScreen.js to send typing keystrokes to ChatKitty, so it can know when a user is typing:

function handleInputTextChanged(text) {
  chatkitty.sendKeystrokes({
    channel: channel,
    keys: text
  });
}

Next, on the GiftedChat component, set the onInputTextChanged prop to handleInputTextChanged.

return (
  <GiftedChat
    messages={messages}
    onSend={handleSend}
    user={mapUser(user)}
    loadEarlier={loadEarlier}
    isLoadingEarlier={isLoadingEarlier}
    onLoadEarlier={handleLoadEarlier}
    onInputTextChanged={handleInputTextChanged} /* Add this */
    renderBubble={renderBubble}
    renderAvatar={renderAvatar}
  />
);

ChatKitty is now able to know when your users start and stop typing.

Next, define a new state variable to track the current typing user.

export default function ChatScreen({ route, navigation }) {
  const { user } = useContext(AuthContext);
  const { channel } = route.params;

  const [messages, setMessages] = useState([]);
  const [loading, setLoading] = useState(true);
  const [loadEarlier, setLoadEarlier] = useState(false);
  const [isLoadingEarlier, setIsLoadingEarlier] = useState(false);
  const [messagePaginator, setMessagePaginator] = useState(null);
  const [typing, setTyping] = useState(null); /* Add this */

  // Unchanged
}

You can now register chat event handlers to control the typing state. Register both onTypingStarted and onTypingStopped in ChatKitty.startChatSession to set the typing state.

useEffect(() => {
  const startChatSessionResult = chatkitty.startChatSession({
    channel: channel,
    onMessageReceived: (message) => {
      setMessages((currentMessages) =>
        GiftedChat.append(currentMessages, [mapMessage(message)])
      );
    },
    onTypingStarted: (typingUser) => { /* Add this */
      if (typingUser.id !== user.id) {
        setTyping(typingUser);
      }
    },
    onTypingStopped: (typingUser) => { /* Add this */
      if (typingUser.id !== user.id) {
        setTyping(null);
      }
    }
  });

  // Unchanged
}, [user, channel]);

typing now holds the current typing user, so you can set the GiftedChat component isTyping prop to typing != null.

return (
  <GiftedChat
    messages={messages}
    onSend={handleSend}
    user={mapUser(user)}
    loadEarlier={loadEarlier}
    isLoadingEarlier={isLoadingEarlier}
    onLoadEarlier={handleLoadEarlier}
    onInputTextChanged={handleInputTextChanged}
    isTyping={typing != null} /* Add this */
    renderBubble={renderBubble}
    renderAvatar={renderAvatar}
  />
);

After these changes, chatScreen.js should look like this:

import React, { useContext, useEffect, useState } from 'react';
import { Avatar, Bubble, GiftedChat } from 'react-native-gifted-chat';

import { chatkitty } from '../chatkitty';
import Loading from '../components/loading';
import { AuthContext } from '../context/authProvider';

export default function ChatScreen({ route, navigation }) {
  const { user } = useContext(AuthContext);
  const { channel } = route.params;

  const [messages, setMessages] = useState([]);
  const [loading, setLoading] = useState(true);
  const [loadEarlier, setLoadEarlier] = useState(false);
  const [isLoadingEarlier, setIsLoadingEarlier] = useState(false);
  const [messagePaginator, setMessagePaginator] = useState(null);
  const [typing, setTyping] = useState(null);

  useEffect(() => {
    const startChatSessionResult = chatkitty.startChatSession({
      channel: channel,
      onMessageReceived: (message) => {
        setMessages((currentMessages) =>
          GiftedChat.append(currentMessages, [mapMessage(message)])
        );
      },
      onTypingStarted: (typingUser) => {
        if (typingUser.id !== user.id) {
          setTyping(typingUser);
        }
      },
      onTypingStopped: (typingUser) => {
        if (typingUser.id !== user.id) {
          setTyping(null);
        }
      }
    });

    chatkitty
      .listMessages({
        channel: channel
      })
      .then((result) => {
        setMessages(result.paginator.items.map(mapMessage));

        setMessagePaginator(result.paginator);
        setLoadEarlier(result.paginator.hasNextPage);

        setLoading(false);
      });

    return startChatSessionResult.session.end;
  }, [user, channel]);

  async function handleSend(pendingMessages) {
    await chatkitty.sendMessage({
      channel: channel,
      body: pendingMessages[0].text
    });
  }

  async function handleLoadEarlier() {
    if (!messagePaginator.hasNextPage) {
      setLoadEarlier(false);

      return;
    }

    setIsLoadingEarlier(true);

    const nextPaginator = await messagePaginator.nextPage();

    setMessagePaginator(nextPaginator);

    setMessages((currentMessages) =>
      GiftedChat.prepend(currentMessages, nextPaginator.items.map(mapMessage))
    );

    setIsLoadingEarlier(false);
  }

  function handleInputTextChanged(text) {
    chatkitty.sendKeystrokes({
      channel: channel,
      keys: text
    });
  }

  function renderBubble(props) {
    return (
      <Bubble
        {...props}
        wrapperStyle={{
          left: {
            backgroundColor: '#d3d3d3'
          }
        }}
      />
    );
  }

  function renderAvatar(props) {
    return (
      <Avatar
        {...props}
        onPressAvatar={(avatarUser) => {
          chatkitty
            .createChannel({
              type: 'DIRECT',
              members: [{ id: avatarUser._id }]
            })
            .then((result) => {
              navigation.navigate('Chat', { channel: result.channel });
            });
        }}
      />
    );
  }

  if (loading) {
    return <Loading />;
  }

  return (
    <GiftedChat
      messages={messages}
      onSend={handleSend}
      user={mapUser(user)}
      loadEarlier={loadEarlier}
      isLoadingEarlier={isLoadingEarlier}
      onLoadEarlier={handleLoadEarlier}
      onInputTextChanged={handleInputTextChanged}
      isTyping={typing != null}
      renderBubble={renderBubble}
      renderAvatar={renderAvatar}
    />
  );
}

function mapMessage(message) {
  return {
    _id: message.id,
    text: message.body,
    createdAt: new Date(message.createdTime),
    user: mapUser(message.user)
  };
}

function mapUser(user) {
  return {
    _id: user.id,
    name: user.displayName,
    avatar: user.displayPictureUrl
  };
}

If you run your app now on a mobile, you should see a typing indicator when someone else starts typing.

Screenshot: Simple typing indicator

Pretty cool! However, the out-of-the-box Gifted Chat typing indicator has a few limitations. Firstly, the in-built indicator doesn't work on Web, so if you deploy your Expo app on the Web, your users won't see this amazing feature. Secondly, although the in-built indicator lets your user know someone is typing, it doesn't tell your users who is typing. It would be nice if we could see the name of the user typing, since a group chat might have multiple active members possibly typing at a time.

Adding a detailed typing indicator​

Gifted Chat lets you add a custom footer to a chat using its renderFooter prop. Let's use this to render a detailed typing status message if a user is currently typing. This footer shows up on Web and gives your users more information.

Screenshot: Detailed typing indicator partial

  • Start by importing StyleSheet and View from react-native, and Text from react-native-paper.

  • Create a helper method renderFooter inside the chatScreen.js component.

  • Define a styles object with styling for the footer <View/> component.

  • Return a <View/> component nesting a <Text/> displaying the typing user if typing with the new styles or null otherwise.

  • Lastly, on the GiftedChat component, set its renderFooter prop to the renderFooter method.

After these changes chatScreen.js should look like this:

import React, { useContext, useEffect, useState } from 'react';
import { StyleSheet, View } from 'react-native';
import { Avatar, Bubble, GiftedChat } from 'react-native-gifted-chat';
import { Text } from 'react-native-paper';

import { chatkitty } from '../chatkitty';
import Loading from '../components/loading';
import { AuthContext } from '../context/authProvider';

export default function ChatScreen({ route, navigation }) {
  const { user } = useContext(AuthContext);
  const { channel } = route.params;

  const [messages, setMessages] = useState([]);
  const [loading, setLoading] = useState(true);
  const [loadEarlier, setLoadEarlier] = useState(false);
  const [isLoadingEarlier, setIsLoadingEarlier] = useState(false);
  const [messagePaginator, setMessagePaginator] = useState(null);
  const [typing, setTyping] = useState(null);

  useEffect(() => {
    const startChatSessionResult = chatkitty.startChatSession({
      channel: channel,
      onMessageReceived: (message) => {
        setMessages((currentMessages) =>
          GiftedChat.append(currentMessages, [mapMessage(message)])
        );
      },
      onTypingStarted: (typingUser) => {
        if (typingUser.id !== user.id) {
          setTyping(typingUser);
        }
      },
      onTypingStopped: (typingUser) => {
        if (typingUser.id !== user.id) {
          setTyping(null);
        }
      }
    });

    chatkitty
      .listMessages({
        channel: channel
      })
      .then((result) => {
        setMessages(result.paginator.items.map(mapMessage));

        setMessagePaginator(result.paginator);
        setLoadEarlier(result.paginator.hasNextPage);

        setLoading(false);
      });

    return startChatSessionResult.session.end;
  }, [user, channel]);

  async function handleSend(pendingMessages) {
    await chatkitty.sendMessage({
      channel: channel,
      body: pendingMessages[0].text
    });
  }

  async function handleLoadEarlier() {
    if (!messagePaginator.hasNextPage) {
      setLoadEarlier(false);

      return;
    }

    setIsLoadingEarlier(true);

    const nextPaginator = await messagePaginator.nextPage();

    setMessagePaginator(nextPaginator);

    setMessages((currentMessages) =>
      GiftedChat.prepend(currentMessages, nextPaginator.items.map(mapMessage))
    );

    setIsLoadingEarlier(false);
  }

  function handleInputTextChanged(text) {
    chatkitty.sendKeystrokes({
      channel: channel,
      keys: text
    });
  }

  function renderBubble(props) {
    return (
      <Bubble
        {...props}
        wrapperStyle={{
          left: {
            backgroundColor: '#d3d3d3'
          }
        }}
      />
    );
  }

  function renderAvatar(props) {
    return (
      <Avatar
        {...props}
        onPressAvatar={(avatarUser) => {
          chatkitty
            .createChannel({
              type: 'DIRECT',
              members: [{ id: avatarUser._id }]
            })
            .then((result) => {
              navigation.navigate('Chat', { channel: result.channel });
            });
        }}
      />
    );
  }

  function renderFooter() {
    if (typing) {
      return (
        <View style={styles.footer}>
          <Text>{typing.displayName} is typing</Text>
        </View>
      );
    }

    return null;
  }

  if (loading) {
    return <Loading />;
  }

  return (
    <GiftedChat
      messages={messages}
      onSend={handleSend}
      user={mapUser(user)}
      loadEarlier={loadEarlier}
      isLoadingEarlier={isLoadingEarlier}
      onLoadEarlier={handleLoadEarlier}
      onInputTextChanged={handleInputTextChanged}
      renderBubble={renderBubble}
      renderAvatar={renderAvatar}
      renderFooter={renderFooter}
    />
  );
}

function mapMessage(message) {
  return {
    _id: message.id,
    text: message.body,
    createdAt: new Date(message.createdTime),
    user: mapUser(message.user)
  };
}

function mapUser(user) {
  return {
    _id: user.id,
    name: user.displayName,
    avatar: user.displayPictureUrl
  };
}

const styles = StyleSheet.create({
  footer: {
    paddingRight: 10,
    paddingLeft: 10,
    paddingBottom: 5
  }
});

With that done, running the app and typing in a chat as another user shows:

Screenshot: Detailed typing indicator

You now have a typing indicator implemented, making your chat app more immersive, great job! Next, let's continue with the immersion by announcing when other users enter or leave a chat.

Adding chat presence notifications​

ChatKitty provides chat session handler methods to handle when users enter and leave a chat. In the previous article, you added Expo notifications to provide push and in-app notifications for your chat app. Let's use this in your chat sessions' onParticipantEnteredChat and onParticipantLeftChat handler methods to notify users when users enter or leave a chat.

In chatScreen.js, let's register chat session handler methods using the notification context sendNotification function we created in part 3 to show a notification when a user enters or leaves the chat.

import { NotificationContext } from '../context/notificationProvider'; // Import notification context

export default function ChatScreen({ route, navigation }) {
  const { sendNotification } = useContext(NotificationContext); // Add this

  //...

  useEffect(() => {
    const startChatSessionResult = chatkitty.startChatSession({
      //...
      onParticipantEnteredChat: (participant) => { /* Add this */
        sendNotification({
          title: `${participant.displayName} entered the chat`
        });
      },
      onParticipantLeftChat: (participant) => { /* Add this */
        sendNotification({
          title: `${participant.displayName} left the chat`
        });
      }
    });

    // Unchanged...
}

After these changes chatScreen.js should look like this:

import React, { useContext, useEffect, useState } from 'react';
import { StyleSheet, View } from 'react-native';
import { Avatar, Bubble, GiftedChat } from 'react-native-gifted-chat';
import { Text } from 'react-native-paper';

import { chatkitty } from '../chatkitty';
import Loading from '../components/loading';
import { AuthContext } from '../context/authProvider';
import { NotificationContext } from '../context/notificationProvider';

export default function ChatScreen({ route, navigation }) {
  const { user } = useContext(AuthContext);
  const { sendNotification } = useContext(NotificationContext);
  const { channel } = route.params;

  const [messages, setMessages] = useState([]);
  const [loading, setLoading] = useState(true);
  const [loadEarlier, setLoadEarlier] = useState(false);
  const [isLoadingEarlier, setIsLoadingEarlier] = useState(false);
  const [messagePaginator, setMessagePaginator] = useState(null);
  const [typing, setTyping] = useState(null);

  useEffect(() => {
    const startChatSessionResult = chatkitty.startChatSession({
      channel: channel,
      onMessageReceived: (message) => {
        setMessages((currentMessages) =>
          GiftedChat.append(currentMessages, [mapMessage(message)])
        );
      },
      onTypingStarted: (typingUser) => {
        if (typingUser.id !== user.id) {
          setTyping(typingUser);
        }
      },
      onTypingStopped: (typingUser) => {
        if (typingUser.id !== user.id) {
          setTyping(null);
        }
      },
      onParticipantEnteredChat: (participant) => {
        sendNotification({
          title: `${participant.displayName} entered the chat`
        });
      },
      onParticipantLeftChat: (participant) => {
        sendNotification({
          title: `${participant.displayName} left the chat`
        });
      }
    });

    chatkitty
      .listMessages({
        channel: channel
      })
      .then((result) => {
        setMessages(result.paginator.items.map(mapMessage));

        setMessagePaginator(result.paginator);
        setLoadEarlier(result.paginator.hasNextPage);

        setLoading(false);
      });

    return startChatSessionResult.session.end;
  }, [user, channel]);

  async function handleSend(pendingMessages) {
    await chatkitty.sendMessage({
      channel: channel,
      body: pendingMessages[0].text
    });
  }

  async function handleLoadEarlier() {
    if (!messagePaginator.hasNextPage) {
      setLoadEarlier(false);

      return;
    }

    setIsLoadingEarlier(true);

    const nextPaginator = await messagePaginator.nextPage();

    setMessagePaginator(nextPaginator);

    setMessages((currentMessages) =>
      GiftedChat.prepend(currentMessages, nextPaginator.items.map(mapMessage))
    );

    setIsLoadingEarlier(false);
  }

  function handleInputTextChanged(text) {
    chatkitty.sendKeystrokes({
      channel: channel,
      keys: text
    });
  }

  function renderBubble(props) {
    return (
      <Bubble
        {...props}
        wrapperStyle={{
          left: {
            backgroundColor: '#d3d3d3'
          }
        }}
      />
    );
  }

  function renderAvatar(props) {
    return (
      <Avatar
        {...props}
        onPressAvatar={(avatarUser) => {
          chatkitty
            .createChannel({
              type: 'DIRECT',
              members: [{ id: avatarUser._id }]
            })
            .then((result) => {
              navigation.navigate('Chat', { channel: result.channel });
            });
        }}
      />
    );
  }

  function renderFooter() {
    if (typing) {
      return (
        <View style={styles.footer}>
          <Text>{typing.displayName} is typing</Text>
        </View>
      );
    }

    return null;
  }

  if (loading) {
    return <Loading />;
  }

  return (
    <GiftedChat
      messages={messages}
      onSend={handleSend}
      user={mapUser(user)}
      loadEarlier={loadEarlier}
      isLoadingEarlier={isLoadingEarlier}
      onLoadEarlier={handleLoadEarlier}
      onInputTextChanged={handleInputTextChanged}
      renderBubble={renderBubble}
      renderAvatar={renderAvatar}
      renderFooter={renderFooter}
    />
  );
}

function mapMessage(message) {
  return {
    _id: message.id,
    text: message.body,
    createdAt: new Date(message.createdTime),
    user: mapUser(message.user)
  };
}

function mapUser(user) {
  return {
    _id: user.id,
    name: user.displayName,
    avatar: user.displayPictureUrl
  };
}

const styles = StyleSheet.create({
  footer: {
    paddingRight: 10,
    paddingLeft: 10,
    paddingBottom: 5
  }
});

If you run your app now, you should see a notification when another user enters a chat. You should also see a notification when the user leaves the chat.

Pretty cool, right? With a typing indicator and presence notifications your users are now more aware of what other users are doing.

Leaving a channel​

If a user is no longer interested in a channel and its discussions, let's give them a way to leave the channel and no longer be a member of that channel. Let's add a long press action to the home screen which when pressed, shows a "leave channel" dialog. React Native Paper provides dialog UI you can use to build the confirmation UI.

Screenshot: Leave channel partial

Edit the homeScreen.js you created earlier in src/screens/ with the following steps:

  • Import Button, Dialog and Portal from react-native-paper
import { useIsFocused } from '@react-navigation/native';
import React, { useEffect, useState } from 'react';
import { FlatList, StyleSheet, View } from 'react-native';
import { Button, Dialog, Divider, List, Portal } from 'react-native-paper'; /* Add this */

  • Add a new state variable to track if the current user wants to leave a channel, storing the selected channel
export default function HomeScreen({ navigation }) {
  const [channels, setChannels] = useState([]);
  const [loading, setLoading] = useState(true);
  const [leaveChannel, setLeaveChannel] = useState(null); /* Add this */

  // Unchanged
}

  • Next create helper methods to handle leaving a selected channel or dismissing the selected channel
function handleLeaveChannel() {
  chatkitty.leaveChannel({ channel: leaveChannel }).then(() => {
    setLeaveChannel(null);

    chatkitty.listChannels({ filter: { joined: true } }).then((result) => {
      setChannels(result.paginator.items);
    });
  });
}

function handleDismissLeaveChannel() {
  setLeaveChannel(null);
}

  • Finally, create a <Dialog/> component to prompt the current user for confirmation when leaving a channel, and use the onLongPress flat list item prop to select a channel to leave by setting leaveChannel state
return (
  <View style={styles.container}>
    <FlatList
      data={channels}
      keyExtractor={(item) => item.id.toString()}
      ItemSeparatorComponent={() => <Divider />}
      renderItem={({ item }) => (
        <List.Item
          title={channelDisplayName(item)}
          description={item.type}
          titleNumberOfLines={1}
          titleStyle={styles.listTitle}
          descriptionStyle={styles.listDescription}
          descriptionNumberOfLines={1}
          onPress={() => navigation.navigate('Chat', { channel: item })}
          onLongPress={() => { /* Add this */
            setLeaveChannel(item);
          }}
        />
      )}
    />
    // Add this
    <Portal>
      <Dialog visible={leaveChannel} onDismiss={handleDismissLeaveChannel}>
        <Dialog.Title>Leave channel?</Dialog.Title>
        <Dialog.Actions>
          <Button onPress={handleDismissLeaveChannel}>Cancel</Button>
          <Button onPress={handleLeaveChannel}>Confirm</Button>
        </Dialog.Actions>
      </Dialog>
    </Portal>
  </View>
);

If you try running your app now, and long press a channel on the home screen, you should see a confirmation dialog asking if you want to leave the channel.

Screenshot: Leave channel

Confirming the dialog prompt should remove the channel from your channels list.

Conclusion​

Amazing! You've completed this tutorial series, and successfully created a robust and full-featured Expo React Native chat app using Gifted Chat powered by ChatKitty. By using Firebase and ChatKitty Chat Functions, you were able to provide a simple yet secure login and registration flow for your users. Using the ChatKitty real-time SDK, you saved time and effort building out real-time messaging complete with features like push notifications, typing indicators, and user presence. That's what I call easy development. 😉

What's Next?​

In the next post, I'll be starting a new series of articles covering how to build chat for Web React projects using the bleeding edge chatscope chat UI kit. Stay tuned for more. 🔥

Like always, if you have any questions, comments or need help with any part of this article, join our Discord Server where you can ask questions, discuss what you're working on, and I'll be more than happy to help.

You can find the complete source code for this project inside this GitHub repository.

👉 Checkout the other blog posts in this series:

This article contains materials adapted from "Chat app with React Native" by Aman Mittal, originally published at Heartbeat.Fritz.Ai.

This article features an image by Volodymyr Hryshchenko.

· 11 min read

Building a Chat App with React Native and Expo (Part 3)

In this tutorial series, I'll be showing you how to build a functional and secure chat app using the latest React Native libraries, including Gifted Chat and the Expo framework powered by the ChatKitty platform.

In the second article of this series, you learned how to use the Gifted Chat React Native library with ChatKitty's JavaScript SDK to build a full featured chat screen with real-time messaging functionality into your app. You also added screens for users to create public channels, discover new channels, and view their channels.

In this tutorial, you'll be using Expo push notifications and ChatKitty Chat Functions to set up local notifications and push notifications to inform users when new messages are received or relevant actions happen inside a channel and across your app.

You can checkout our Expo React Native sample code any time on GitHub.

After reading this article, you will be able to:

  1. Implement local notifications for users to see what's happening from another screen

  2. Use ChatKitty user properties to store arbitrary data related to your users like expo push tokens

  3. Use Expo push notifications and ChatKitty Chat Functions to implement push notifications

If you followed along the last article, you should already have the ChatKitty JavaScript SDK NPM package added to your Expo React Native project.


Before we begin, let's go over some terms we'll be using a lot in this article.

What are local notifications?​

Local notifications are messages that pop up while your app is in-use to inform a user of relevant actions related to another screen in your application from their current screen. ChatKitty sends notifications to your app through the ChatKitty JavaScript SDK. You can listen for these notifications and use them to build in-app notification views.

What are push notifications?​

Push notifications are short messages sent to mobile devices to alert a user when something of interests happen, and provide information related to that event even when your app isn't currently in-use. Push notifications are a great way to engage your users and improve your customer experience. Push notifications are a critical part of most chat apps and have traditionally been difficult to implement. However, the Expo framework provides seamless support for push notifications, simplifying the process of send push notifications to your users.

Installing notification libraries​

For this project, you'll be using Expo push notifications. So, install the Expo notifications, and other dependency modules you'll need to get expo push tokens which are needed to register user devices for push notifications:

npx expo install expo-device expo-notifications

Let's also install the EAS CLI. EAS Build is a hosted service for building app binaries for your Expo and React Native projects. You will be using it to set up and handle Expo push notification credentials.

npm install -g eas-cli

Setting up Expo push notification credentials​

info

Check out the official Expo push notifications guide for more information on setting up Expo push notification as things change,

For iOS, the managed Expo workflow handles push notification credentials automatically when you register your device and run the eas build command. However, for Android you'll need to add an Android app to your Firebase project, update your project, and upload your FCM server credentials to Expo.

Adding Firebase credentials to the app​

From the Firebase console side menu, go to your "Project settings".

Screenshot: Firebase project settings

Go to the "Your apps" section and click the Android icon:

Screenshot: Screenshot: Firebase add app

Fill out the application details and register your android app

Screenshot: Screenshot: Firebase create android app register

Download the google-services.json file and add it to your Expo React Native project's root directory

Screenshot: Screenshot: Firebase create android app download

In your app.json inside your project's root directory, add an android.googleServicesFile property with the relative path to the google-services.json file, as well as an android.package property with your app's Android package name:

{
  "expo": {
    ...
    "android": {
      "package": "com.yourpackage.yourcoolapp",
      "googleServicesFile": "./google-services.json"
    }
    ...
  }
}

Uploading FCM Server Credentials to Expo​

To allow Expo to send push notifications to your Android app, you'll need to upload your FCM server key. Before you can upload your server key to Expo, you'll need to create an Expo account.

To get your FCM server key, go to "Project Settings" section of your Firebase project, then go to the "Cloud Messaging" tab. As you will see, Server Key is only available in Cloud Messaging API (Legacy), which is disabled by default, so you will need to enable it.

Screenshot: Enable Firebase Cloud Messaging API

Once you have enabled this, you can copy the server key listed next to the token.

Screenshot: Firebase Cloud Messaging server key

Now, go to the "Credentials" section under the "Account Settings" option from your Expo account's dashboard side menu, and upload the required credentials to Expo.

To run a local Android build, you will need to run this command as well:

eas build --platform android --local

Getting a user's expo push token​

To send a push notification to a user using Expo, we'll need their expo push token. Once we get the expo push token, we can then store it as a ChatKitty user property, so we can access it later in a chat function or on a back-end.

We'll interface with Expo notifications using a new context provider. Inside the src/context/ directory, create a new file notificationProvider.js. We'll define a new context and provider component to register the user's device for push notifications and update the current ChatKitty user's properties to store their Expo device token.

src/context/notificationProvider.js
import { createContext, useEffect, useRef, useState } from 'react';
import { Platform } from 'react-native';

import * as Device from 'expo-device';
import * as Notifications from 'expo-notifications';
import { chatkitty } from '../chatkitty';

Notifications.setNotificationHandler({
  handleNotification: async () => ({
    shouldShowAlert: true,
    shouldPlaySound: false,
    shouldSetBadge: false
  })
});

export const NotificationContext = createContext({});

export const NotificationProvider = ({ children }) => {
  const [notification, setNotification] = useState(null);
  const notificationListener = useRef();
  const responseListener = useRef();

  useEffect(() => {
    notificationListener.current =
      Notifications.addNotificationReceivedListener((notification) => {
        setNotification(notification);
      });

    responseListener.current =
      Notifications.addNotificationResponseReceivedListener((response) => {
        console.log(response);
      });

    return () => {
      Notifications.removeNotificationSubscription(
        notificationListener.current
      );
      Notifications.removeNotificationSubscription(responseListener.current);
    };
  }, []);

  return (
    <NotificationContext.Provider
      value={{
        notification,
        registerForPushNotifications: async () => {
          let token;
          if (Device.isDevice) {
            const { status: existingStatus } = await Notifications.getPermissionsAsync();
            let finalStatus = existingStatus;
            if (existingStatus !== 'granted') {
              const { status } = await Notifications.requestPermissionsAsync();
              finalStatus = status;
            }
            if (finalStatus !== 'granted') {
              alert('Failed to get push token for push notification!');
              return;
            }
            token = (await Notifications.getExpoPushTokenAsync()).data;
            console.log(token);
          } else {
            alert('Must use physical device for Push Notifications');
          }

          if (Platform.OS === 'android') {
            await Notifications.setNotificationChannelAsync('default', {
              name: 'default',
              importance: Notifications.AndroidImportance.MAX,
              vibrationPattern: [0, 250, 250, 250],
              lightColor: '#FF231F7C'
            });
          }

          await chatkitty.updateCurrentUser((user) => {
            user.properties = {
              ...user.properties,
              'expo-push-token': token
            };
            return user;
          });
        }
      }}
    >
      {children}
    </NotificationContext.Provider>
  );
};

Later, we'll be updating the notification provider to send local notifications.

To get the notification context inside your app components, wrap the app routes with notification provider.

Edit the src/context/index.js file to wrap the app routes with the notification provider.

The index.js file should now contain:

src/context/index.js
import React from 'react';
import { DefaultTheme, Provider as PaperProvider } from 'react-native-paper';

import { AuthProvider } from './authProvider';
import { NotificationProvider } from './notificationProvider';
import Routes from './routes';

export default function Providers() {
  return (
      <PaperProvider theme={theme}>
        <AuthProvider>
          <NotificationProvider>
            <Routes />
          </NotificationProvider>
        </AuthProvider>
      </PaperProvider>
  );
}

const theme = {
  ...DefaultTheme,
  roundness: 2,
  colors: {
    ...DefaultTheme.colors,
    primary: '#5b3a70',
    accent: '#50c878',
    background: '#f7f9fb'
  }
};

Next, update homeStack.js to call registerForPushNotifications from the notification context.

src/context/homeStack.js
import React, { useContext, useEffect } from 'react';
import { NotificationContext } from './notificationProvider';

export default function HomeStack() {
  const { registerForPushNotifications } = useContext(NotificationContext);

  useEffect(() => {
    registerForPushNotifications();
  }, []);

  // Unchanged
}

With that, you should have the user's expo push token as the expo-push-token user property. With Expo set up, let's create a ChatKitty chat function to use Expo to send a push notification when a ChatKitty notification event happens.

Adding Expo to your Chat Runtime​

ChatKitty makes it easy to integrate your back-end and external services like Expo into a ChatKitty application using Chat Functions. Chat Functions let you write arbitrary code that runs any time a relevant event or action happens inside your app. We'll be using a chat function to send a push notification whenever an event occurs that a user should be notified about, and the user isn't online. With ChatKitty, you can use any NPM package inside your Chat Functions as a Chat Runtime dependency.

From your ChatKitty application dashboard, go to the "Functions" page:

Screenshot: ChatKitty side menu functions

Go to the "Runtime" tab and add a new dependency to the Expo Server SDK NPM package, expo-server-sdk. Version 3.7.0 was the latest version as of the time this article was written.

Screenshot: ChatKitty runtime add expo Remember to click the "Save" icon to confirm your chat runtime dependencies changes.

Now we're ready to define a chat function to send a push notification using Expo, whenever a user should be notified about an event, and the user is offline.

Sending push notifications using a chat function​

From your ChatKitty application dashboard, go to the "Functions" page and select the "User Received Notification" event chat function:

Screenshot: ChatKitty chat functions

This chat function runs whenever an event a user can be notified about happens. Edit the chat function to send a push notification if the user isn't currently online.

const { Expo } = require('expo-server-sdk');

const expo = new Expo(); // create Expo client

async function handleEvent(
  event: UserReceivedNotificationEvent,
  context: Context
) {
  if (event.userHasActiveSession) return; // skip if this user is online

  const expoPushToken = event.user.properties['expo-push-token']; // get the expo push token registered

  if (!expoPushToken || !Expo.isExpoPushToken(expoPushToken)) return; // check expo push token is present and valid

  const notification = event.notification;

  // send push notification with Expo
  await expo.sendPushNotificationsAsync([
    {
      to: expoPushToken,
      sound: 'default',
      title: notification.title,
      body: notification.body,
      data: notification.data
    }
  ]);
}

Screenshot: ChatKitty chat function user received notification Remember to click the "Save" icon to confirm your chat function changes.

If you close the app now, and send a message from another device as another user, you should see a push notification:

Screenshot: Push notification

Handling local notifications with Expo​

Now that we have Expo push notifications set up, let's also handle local notifications with Expo.

To send local notifications, let's add a sendNotification function to notificationProvider.js that schedules a local Expo notification and export it in the notification context:

src/context/notificationProvider.js
export const NotificationProvider = ({ children }) => {
  // Unchanged...

  return (
    <NotificationContext.Provider
      value={{
        notification,
        sendNotification: async (content) => {
          await Notifications.scheduleNotificationAsync({
            content,
            trigger: null
          });
        },
        registerForPushNotifications: async () => { /* Unchanged */}
      }}
    >
      {children}
    </NotificationContext.Provider>
  );
};

Next, in homeStack.js register a ChatKitty onNotificationReceived event listener in the useEffect React hook to show received in-app notifications:

src/context/homeStack.js
import {chatkitty} from '../chatkitty';

export default function HomeStack() {
  const {registerForPushNotifications, sendNotification} = useContext(NotificationContext);

  useEffect(()=> {
    registerForPushNotifications();

    chatkitty.onNotificationReceived(async (notification) => {
      await sendNotification({
        title: notification.title,
        body: notification.body
      });
    });
  }, []);

  // Unchanged...
}

Conclusion​

Pretty cool, you've completed the third part of this tutorial series and successfully implemented push notifications, using the Expo framework and ChatKitty Chat Functions. You've also implemented local notifications that seamlessly inform your users when something they care about happens. Your users are now always in the loop.

What's next?​

In the next post of this series, we'll be enhancing your chat app's user experience with direct messaging, typing indicators, and chat presence notifications. Stay tuned for more. 🔥

If you have any questions, comments or need help with any part of this article, join our Discord Server where you can ask questions, discuss what you're working on, and I'll be more than happy to help.

You can find the complete source code for this project inside this GitHub repository.

👉 Checkout the other blog posts in this series:

This article contains materials adapted from "Chat app with React Native" by Aman Mittal, originally published at Heartbeat.Fritz.Ai.

This article features an image by Volodymyr Hryshchenko.

· 18 min read

Building a Chat App with React Native and Gifted Chat (Part 2)

In this tutorial series , I'll be showing you how to build a functional and secure chat app using the latest React Native libraries, including Gifted Chat and the Expo framework powered by the ChatKitty platform.

In the first article of this series, you learned how to use Firebase along with ChatKitty Chat Functions to implement a secure yet simple user login flow by proxying Firebase Authentication through ChatKitty. Along with that, you built a couple of screens with the react-native-paper UI library to allow users to register for your chat app and login into the app.

In this tutorial, you'll be using the Gifted Chat React Native library to create a full-featured chat screen with its out of the box features. You'll also use ChatKitty's JavaScript Chat SDK to add real-time messaging to your chat app.

After reading this article, you will be able to:

  1. Create public channels for users to join

  2. View all channels a user can join and discover channels created by other users

  3. Integrate the react-native-gifted-chat library to implement a group chat screen

You can check out our Expo React Native sample code any time on GitHub.

If you followed along the last article, you should already have the ChatKitty JavaScript SDK NPM package added to your Expo React Native project.


Before we begin, let's go over some terms we'll be using a lot in this article.

What are channels?​

Channels are the backbone of the ChatKitty chat experience. Users can join channels and receive or send messages. ChatKitty broadcasts messages created in channels to channel member users with active chat sessions and sends notifications to offline members.

What are chat sessions?​

Before a user can begin sending and receiving real-time messages and use in-app chat features like typing indicators, delivery and read receipts, live reactions, etc, their device needs to start a chat session. A user device can start up to 10 chat sessions at a time but usually have only a maximum of one active at a time. You can think of an active chat session as corresponding to being in a "chat room", when the user "leaves" the chat room, its chat session ends.

With that, you have all the information you need build to chat into your app.

Let's go! 🏎️

First, you'll start by creating a screen that shows a list of channels a user can chat in after logging in.

Displaying a user's channels​

Start by changing the homeScreen.js you previously created to list the channels a logged-in user is a member of.

The homeScreen.js file should contain:

src/screens/homeScreen.js
import { useIsFocused } from '@react-navigation/native';
import React, { useEffect, useState } from 'react';
import { FlatList, StyleSheet, View } from 'react-native';
import { Divider, List } from 'react-native-paper';

import { chatkitty } from '../chatkitty';
import Loading from '../components/loading';

export default function HomeScreen() {
  const [channels, setChannels] = useState([]);
  const [loading, setLoading] = useState(true);

  const isFocused = useIsFocused();

  useEffect(() => {
    let isCancelled = false;

    chatkitty.listChannels({ filter: { joined: true } }).then((result) => {
      if (!isCancelled) {
        setChannels(result.paginator.items);

        if (loading) {
          setLoading(false);
        }
      }
    });

    return () => {
      isCancelled = true;
    };
  }, [isFocused, loading]);

  if (loading) {
    return <Loading />;
  }

  return (
    <View style={styles.container}>
      <FlatList
        data={channels}
        keyExtractor={(item) => item.id.toString()}
        ItemSeparatorComponent={() => <Divider />}
        renderItem={({ item }) => (
          <List.Item
            title={item.name}
            description={item.type}
            titleNumberOfLines={1}
            titleStyle={styles.listTitle}
            descriptionStyle={styles.listDescription}
            descriptionNumberOfLines={1}
            onPress={() => {
              // TODO navigate to a chat screen.
            }}
          />
        )}
      />
    </View>
  );
}

const styles = StyleSheet.create({
  container: {
    backgroundColor: '#f5f5f5',
    flex: 1
  },
  listTitle: {
    fontSize: 22
  },
  listDescription: {
    fontSize: 16
  }
});

If you run the app and log in now, it shouldn't look like much.

Screenshot: Home screen empty

Pretty empty, huh? Soon you'll create a screen responsible for creating new channels, so the home screen can be populated.

Creating shared header components and a modal stack navigator​

Before we create the CreateChannel screen, we should modify the app header bar to share options across different screens. The CreateChannel screen will be implemented as a modal, so we'll also need a separate stack navigator to wrap the home stack navigator and handle modals. Modals are screens that block interactions with the main view when displaying their content.

Modify your homeStack.js file in the src/context/ directory to apply header bar options across screens and define a stack navigator for app modal screens.

The homeStack.js file should contain:

src/context/homeStack.js
import { createStackNavigator } from '@react-navigation/stack';
import React from 'react';

import HomeScreen from '../screens/homeScreen';

const ChatStack = createStackNavigator();
const ModalStack = createStackNavigator();

export default function HomeStack() {
  return (
    <ModalStack.Navigator screenOptions={{
      headerShown: false,
      presentation: 'modal'
    }}>
      <ModalStack.Screen name='ChatApp' component={ChatComponent} />
    </ModalStack.Navigator>
  );
}

function ChatComponent() {
  return (
    <ChatStack.Navigator
      screenOptions={{
        headerStyle: {
          backgroundColor: '#5b3a70'
        },
        headerTintColor: '#ffffff',
        headerTitleStyle: {
          fontSize: 22
        }
      }}
    >
      <ChatStack.Screen name='Home' component={HomeScreen} />
    </ChatStack.Navigator>
  );
}

Creating a channel creation screen​

Now we can create a new screen file createChannelScreen.js inside the src/screens/ directory. From this screen, users will create new public channels other users can join and chat in.

The createChannelScreen.js file should contain:

src/screens/createChannelScreen.js
import React, { useState } from 'react';
import { StyleSheet, View } from 'react-native';
import { IconButton, Title } from 'react-native-paper';

import { chatkitty } from '../chatkitty';
import FormButton from '../components/formButton';
import FormInput from '../components/formInput';

export default function CreateChannelScreen({ navigation }) {
  const [channelName, setChannelName] = useState('');

  function handleButtonPress() {
    if (channelName.length > 0) {
      chatkitty
        .createChannel({
          type: 'PUBLIC',
          name: channelName
        })
        .then(() => navigation.navigate('Home'));
    }
  }

  return (
    <View style={styles.rootContainer}>
      <View style={styles.closeButtonContainer}>
        <IconButton
          icon='close-circle'
          size={36}
          iconColor='#5b3a70'
          onPress={() => navigation.goBack()}
        />
      </View>
      <View style={styles.innerContainer}>
        <Title style={styles.title}>Create a new channel</Title>
        <FormInput
          labelName='Channel Name'
          value={channelName}
          onChangeText={(text) => setChannelName(text)}
          clearButtonMode='while-editing'
        />
        <FormButton
          title='Create'
          modeValue='contained'
          labelStyle={styles.buttonLabel}
          onPress={() => handleButtonPress()}
          disabled={channelName.length === 0}
        />
      </View>
    </View>
  );
}

const styles = StyleSheet.create({
  rootContainer: {
    flex: 1
  },
  closeButtonContainer: {
    position: 'absolute',
    top: 30,
    right: 0,
    zIndex: 1
  },
  innerContainer: {
    flex: 1,
    justifyContent: 'center',
    alignItems: 'center'
  },
  title: {
    fontSize: 24,
    marginBottom: 10
  },
  buttonLabel: {
    fontSize: 22
  }
});

Okay, let's test the CreateChannel screen by adding a temporary button to open the screen in our home screen header bar, and creating a new channel.

The homeStack.js file should contain:

src/context/homeStack.js
import { createStackNavigator } from '@react-navigation/stack';
import React from 'react';
import { IconButton } from 'react-native-paper';

import CreateChannelScreen from '../screens/createChannelScreen';
import HomeScreen from '../screens/homeScreen';

const ChatStack = createStackNavigator();
const ModalStack = createStackNavigator();

export default function HomeStack() {
  return (
    <ModalStack.Navigator screenOptions={{
      headerShown: false,
      presentation: 'modal'
    }}>
      <ModalStack.Screen name='ChatApp' component={ChatComponent} />
      <ModalStack.Screen name='CreateChannel' component={CreateChannelScreen} />
    </ModalStack.Navigator>
  );
}

function ChatComponent() {
  return (
    <ChatStack.Navigator
      screenOptions={{
        headerStyle: {
          backgroundColor: '#5b3a70'
        },
        headerTintColor: '#ffffff',
        headerTitleStyle: {
          fontSize: 22
        }
      }}
    >
      <ChatStack.Screen
        name='Home'
        component={HomeScreen}
        options={({ navigation }) => ({
          headerRight: () => (
            <IconButton
              icon='plus'
              size={28}
              iconColor='#ffffff'
              onPress={() => navigation.navigate('CreateChannel')}
            />
          )
        })}
      />
    </ChatStack.Navigator>
  );
}

If you run the app now, you should see a plus icon in the header bar:

Screenshot: Home screen add

Tap the button and create a new channel:

Screenshot: Create channel screen

Tap "Create", and you should be redirected back to the home screen with your new channel:

Screenshot: Home screen added

You now have a channel to send messages, receive messages and chat in. Next, let's get started building a channel chat screen with the react-native-gifted-chat library.

Creating a chat screen​

Gifted Chat is an open-source React Native library that saves you tons of time and development effort building chat UIs. The library is extensible and customizable with a large online community making it a great option to build chat.

To use Gifted Chat, add its NPM package to your Expo React Native project:

npx expo install react-native-gifted-chat

Next, create a file chatScreen.js inside the src/screens/ directory. This screen will render a chat screen for users to send new messages and view messages they've sent and received. We'll be updating this screen throughout the rest of this tutorial series to add more advanced and sophisticated chat features.

chatScreen.js will need quite a few things, so let's break down what you'll be doing:

  • Import GiftedChat since we need a GiftedChat component to add the chat UI and functionality.

  • Retrieve the current user from our authentication context, so we can show messages as created by the current user and perform other current user specific functions.

  • Retrieve the channel to start this chat with using the route props.

  • Create a ChatScreen functional React component, and inside it define a messages state variable. This array will hold message data objects representing the chat message history. This variable is initially an empty array.

  • Define a couple of helper functions mapUser and mapMessage to map the current user and message objects we get from ChatKitty into a schema Gifted Chat recognizes.

  • Use an useEffect React hook to start a new chat session with the ChatScreen channel using the ChatKitty startChatSession function. Register an onMessageReceived function that appends new messages received from ChatKitty into the existing Gifted Chat managed messages, and replace the messages state when a new message is received. After starting the chat session, fetch the channel's last messages using listMessages then replace the messages state. As part of cleaning up when the component is about to be destroyed, return the ChatSession's end function to the useEffect function to end the chat session and free up ChatKitty resources.

  • Define a helper function handleSend, to send a new message using the ChatKitty sendMessage function.

  • Return to be rendered a GiftedChat with the messages state, a mapped GiftedChat current user chatUser, and the handleSend helper function.

The chatScreen.js file should contain:

src/screens/chatScreen.js
import React, { useContext, useEffect, useState } from 'react';
import { Bubble, GiftedChat } from 'react-native-gifted-chat';

import { chatkitty } from '../chatkitty';
import Loading from '../components/loading';
import { AuthContext } from '../context/authProvider';

export default function ChatScreen({ route }) {
  const { user } = useContext(AuthContext);
  const { channel } = route.params;

  const [messages, setMessages] = useState([]);
  const [loading, setLoading] = useState(true);

  useEffect(() => {
    const startChatSessionResult = chatkitty.startChatSession({
      channel: channel,
      onMessageReceived: (message) => {
        setMessages((currentMessages) =>
          GiftedChat.append(currentMessages, [mapMessage(message)])
        );
      }
    });

    chatkitty
      .listMessages({
        channel: channel
      })
      .then((result) => {
        setMessages(result.paginator.items.map(mapMessage));

        setLoading(false);
      });

    return startChatSessionResult.session.end;
  }, [user, channel]);

  async function handleSend(pendingMessages) {
    await chatkitty.sendMessage({
      channel: channel,
      body: pendingMessages[0].text
    });
  }

  function renderBubble(props) {
    return (
      <Bubble
        {...props}
        wrapperStyle={{
          left: {
            backgroundColor: '#d3d3d3'
          }
        }}
      />
    );
  }

  if (loading) {
    return <Loading />;
  }

  return (
    <GiftedChat
      messages={messages}
      onSend={handleSend}
      user={mapUser(user)}
      renderBubble={renderBubble}
    />
  );
}

function mapMessage(message) {
  return {
    _id: message.id,
    text: message.body,
    createdAt: new Date(message.createdTime),
    user: mapUser(message.user)
  };
}

function mapUser(user) {
  return {
    _id: user.id,
    name: user.displayName,
    avatar: user.displayPictureUrl
  };
}

Now, let's add the Chat screen to the home stack navigator. Edit homeStack.js in src/context/ with a new screen entry.

The homeStack.js file should contain:

src/context/homeStack.js
import { createStackNavigator } from '@react-navigation/stack';
import React from 'react';
import { IconButton } from 'react-native-paper';

import ChatScreen from '../screens/chatScreen';
import CreateChannelScreen from '../screens/createChannelScreen';
import HomeScreen from '../screens/homeScreen';

const ChatStack = createStackNavigator();
const ModalStack = createStackNavigator();

export default function HomeStack() {
  return (
    <ModalStack.Navigator screenOptions={{
      headerShown: false,
      presentation: 'modal'
    }}>
      <ModalStack.Screen name='ChatApp' component={ChatComponent} />
      <ModalStack.Screen name='CreateChannel' component={CreateChannelScreen} />
    </ModalStack.Navigator>
  );
}

function ChatComponent() {
  return (
    <ChatStack.Navigator
      screenOptions={{
        headerStyle: {
          backgroundColor: '#5b3a70'
        },
        headerTintColor: '#ffffff',
        headerTitleStyle: {
          fontSize: 22
        }
      }}
    >
      <ChatStack.Screen
        name='Home'
        component={HomeScreen}
        options={({ navigation }) => ({
          headerRight: () => (
            <IconButton
              icon='plus'
              size={28}
              iconColor='#ffffff'
              onPress={() => navigation.navigate('CreateChannel')}
            />
          )
        })}
      />
      <ChatStack.Screen
        name='Chat'
        component={ChatScreen}
        options={({ route }) => ({
          title: route.params.channel.name
        })}
      />
    </ChatStack.Navigator>
  );
}

Before we can begin chatting, you'll need to update the homeScreen.js component to redirect to a Channel screen.

The homeScreen.js file should contain:

src/screens/homeScreen.js
import { useIsFocused } from '@react-navigation/native';
import React, { useEffect, useState } from 'react';
import { FlatList, StyleSheet, View } from 'react-native';
import { Divider, List } from 'react-native-paper';

import { chatkitty } from '../chatkitty';
import Loading from '../components/loading';

export default function HomeScreen({ navigation }) {
  const [channels, setChannels] = useState([]);
  const [loading, setLoading] = useState(true);

  const isFocused = useIsFocused();

  useEffect(() => {
    let isCancelled = false;

    chatkitty.listChannels({ filter: { joined: true } }).then((result) => {
      if (!isCancelled) {
        setChannels(result.paginator.items);

        if (loading) {
          setLoading(false);
        }
      }
    });

    return () => {
      isCancelled = true;
    };
  }, [isFocused, loading]);

  if (loading) {
    return <Loading />;
  }

  return (
    <View style={styles.container}>
      <FlatList
        data={channels}
        keyExtractor={(item) => item.id.toString()}
        ItemSeparatorComponent={() => <Divider />}
        renderItem={({ item }) => (
          <List.Item
            title={item.name}
            description={item.type}
            titleNumberOfLines={1}
            titleStyle={styles.listTitle}
            descriptionStyle={styles.listDescription}
            descriptionNumberOfLines={1}
            onPress={() => navigation.navigate('Chat', { channel: item })}
          />
        )}
      />
    </View>
  );
}

const styles = StyleSheet.create({
  container: {
    backgroundColor: '#f5f5f5',
    flex: 1
  },
  listTitle: {
    fontSize: 22
  },
  listDescription: {
    fontSize: 16
  }
});

If you run the app, you should now be able to send messages in the channel you created:

Screenshot: Channel chat screen sent message

Awesome! You've successfully added chat into your app. However, before we bring out the champagne there's a couple of things we should do. Firstly, we're currently only getting a slice of the channel message history, as the ChatKitty API paginates all collections. Currently, if the channel had more than the default messages page size (25 items) messages, then the messages response would be truncated and messages older than the 25th message would not be returned.

Screenshot: Channel chat screen no pagination

We can't see messages before 25.

Secondly, although it's nice we can chat with ourselves, it'll be really cool if users can find channels created by other users, or by your backend that they have permission to join. We can create a browse channel screen for users to see public channels created by other users.

Loading earlier messages​

To load older messages in pages before the last channel page, we can use the paginator object returned with the ChatKitty listMessages result to fetch more pages and prepend the messages fetched into our messages collection.

// Fetching a next page:

const result = chatkitty.listMessages({ channel: channel });

const paginator = result.paginator; // paginator from result

if (paginator.hasNextPage) { // check if there are more pages
  const nextPaginator = await messagePaginator.nextPage();

  const nextMessages = nextPaginator.items;
}

Now, let's use paginators to load more messages into our chat. Edit the chatScreen.js file in src/screens/ to load more messages using Gifted Chat.

The chatScreen.js file should contain:

src/screens/chatScreen.js
import React, { useContext, useEffect, useState } from 'react';
import { Bubble, GiftedChat } from 'react-native-gifted-chat';

import { chatkitty } from '../chatkitty';
import Loading from '../components/loading';
import { AuthContext } from '../context/authProvider';

export default function ChatScreen({ route }) {
  const { user } = useContext(AuthContext);
  const { channel } = route.params;

  const [messages, setMessages] = useState([]);
  const [loading, setLoading] = useState(true);
  const [loadEarlier, setLoadEarlier] = useState(false);
  const [isLoadingEarlier, setIsLoadingEarlier] = useState(false);
  const [messagePaginator, setMessagePaginator] = useState(null);

  useEffect(() => {
    const startChatSessionResult = chatkitty.startChatSession({
      channel: channel,
      onMessageReceived: (message) => {
        setMessages((currentMessages) =>
          GiftedChat.append(currentMessages, [mapMessage(message)])
        );
      }
    });

    chatkitty
      .listMessages({
        channel: channel
      })
      .then((result) => {
        setMessages(result.paginator.items.map(mapMessage));

        setMessagePaginator(result.paginator);
        setLoadEarlier(result.paginator.hasNextPage);

        setLoading(false);
      });

    return startChatSessionResult.session.end;
  }, [user, channel]);

  async function handleSend(pendingMessages) {
    await chatkitty.sendMessage({
      channel: channel,
      body: pendingMessages[0].text
    });
  };

  async function handleLoadEarlier() {
    if (!messagePaginator.hasNextPage) {
      setLoadEarlier(false);

      return;
    }

    setIsLoadingEarlier(true);

    const nextPaginator = await messagePaginator.nextPage();

    setMessagePaginator(nextPaginator);

    setMessages((currentMessages) =>
      GiftedChat.prepend(currentMessages, nextPaginator.items.map(mapMessage))
    );

    setIsLoadingEarlier(false);
  }

  function renderBubble(props) {
    return (
      <Bubble
        {...props}
        wrapperStyle={{
          left: {
            backgroundColor: '#d3d3d3'
          }
        }}
      />
    );
  }

  if (loading) {
    return <Loading />;
  }

  return (
    <GiftedChat
      messages={messages}
      onSend={handleSend}
      user={mapUser(user)}
      loadEarlier={loadEarlier}
      isLoadingEarlier={isLoadingEarlier}
      onLoadEarlier={handleLoadEarlier}
      renderBubble={renderBubble}
    />
  );
}

function mapMessage(message) {
  return {
    _id: message.id,
    text: message.body,
    createdAt: new Date(message.createdTime),
    user: mapUser(message.user)
  };
}

function mapUser(user) {
  return {
    _id: user.id,
    name: user.displayName,
    avatar: user.displayPictureUrl
  };
}

If you run the app now, you should see an option to load more messages if you have a lot of messages.

Screenshot: Channel chat screen paginated

If you tap it, the next set of messages loads, repeatable until the beginning of the conversation.

Screenshot: Channel chat screen paginated loaded more

Much better. Now, let's provide a screen for users to discover new channels.

Creating a browse channels screen​

The browse channels screen is going to be very similar to the home screen, but instead of listing channels a user is already a member of, it will list channels a user can join.

Create a new file browseChannelsScreen.js in src/screens/. This component will display a list of joinable channels from ChatKitty.

The browseChannelsScreen.js file should contain:

src/screens/browseChannelsScreen.js
import { useIsFocused } from '@react-navigation/native';
import React, { useEffect, useState } from 'react';
import { FlatList, StyleSheet, View } from 'react-native';
import { Divider, List } from 'react-native-paper';

import { chatkitty } from '../chatkitty';
import Loading from '../components/loading';

export default function BrowseChannelsScreen({ navigation }) {
  const [channels, setChannels] = useState([]);
  const [loading, setLoading] = useState(true);

  const isFocused = useIsFocused();

  useEffect(() => {
    chatkitty.listChannels({ filter: { joined: false } }).then((result) => {
      setChannels(result.paginator.items);

      if (loading) {
        setLoading(false);
      }
    });
  }, [isFocused, loading]);

  async function handleJoinChannel(channel) {
    const result = await chatkitty.joinChannel({ channel: channel });

    navigation.navigate('Chat', { channel: result.channel });
  }

  if (loading) {
    return <Loading />;
  }

  return (
    <View style={styles.container}>
      <FlatList
        data={channels}
        keyExtractor={(item) => item.id.toString()}
        ItemSeparatorComponent={() => <Divider />}
        renderItem={({ item }) => (
          <List.Item
            title={item.name}
            description={item.type}
            titleNumberOfLines={1}
            titleStyle={styles.listTitle}
            descriptionStyle={styles.listDescription}
            descriptionNumberOfLines={1}
            onPress={() => handleJoinChannel(item)}
          />
        )}
      />
    </View>
  );
}

const styles = StyleSheet.create({
  container: {
    backgroundColor: '#f5f5f5',
    flex: 1
  },
  listTitle: {
    fontSize: 22
  },
  listDescription: {
    fontSize: 16
  }
});

Next, let's add our new screen to our home stack. Open the homeStack.js file in src/context/ and add the BrowseChannels screen. Also, let's make it so that clicking the "Add" icon button from the home screen takes us to the BrowseChannels screen. Then, let's create another "Add" icon button for the BrowseChannel screen that now opens the CreateChannel screen.

The homeStack.js file should contain:

src/context/homeStack.js
import { createStackNavigator } from '@react-navigation/stack';
import React from 'react';
import { IconButton } from 'react-native-paper';

import BrowseChannelsScreen from '../screens/browseChannelsScreen';
import ChatScreen from '../screens/chatScreen';
import CreateChannelScreen from '../screens/createChannelScreen';
import HomeScreen from '../screens/homeScreen';

const ChatStack = createStackNavigator();
const ModalStack = createStackNavigator();

export default function HomeStack() {
  return (
    <ModalStack.Navigator screenOptions={{ headerShown: false, presentation: 'modal' }}>
      <ModalStack.Screen name='ChatApp' component={ChatComponent} />
      <ModalStack.Screen name='CreateChannel' component={CreateChannelScreen} />
    </ModalStack.Navigator>
  );
}

function ChatComponent() {
  return (
    <ChatStack.Navigator
      screenOptions={{
        headerStyle: {
          backgroundColor: '#5b3a70'
        },
        headerTintColor: '#ffffff',
        headerTitleStyle: {
          fontSize: 22
        }
      }}
    >
      <ChatStack.Screen
        name='Home'
        component={HomeScreen}
        options={({ navigation }) => ({
          headerRight: () => (
            <IconButton
              icon='plus'
              size={28}
              iconColor='#ffffff'
              onPress={() => navigation.navigate('BrowseChannels')}
            />
          )
        })}
      />
      <ChatStack.Screen
        name='BrowseChannels'
        component={BrowseChannelsScreen}
        options={({ navigation }) => ({
          headerRight: () => (
            <IconButton
              icon='plus'
              size={28}
              iconColor='#ffffff'
              onPress={() => navigation.navigate('CreateChannel')}
            />
          )
        })}
      />
      <ChatStack.Screen
        name='Chat'
        component={ChatScreen}
        options={({ route }) => ({
          title: route.params.channel.name
        })}
      />
    </ChatStack.Navigator>
  );
}

Let's test the browse channels functionality by logging in as another user.

Screenshot: Login

After logging in, if you navigate to the browse screen using the "Add" icon button, you should see the channel created earlier by the other user.

Screenshot: Browse channels screen

Let's say hello!

Screenshot: Channel chat screen another user

Conclusion​

Amazing, you've completed the second part of this tutorial series and made your chat app even better. By implementing screens and functionality to allow users to create, discover and join channels, your users can beginning having meaningful conversations. You also used the Gifted Chat React Native library and ChatKitty to build a chat screen to send and receive real-time messages in minutes. It doesn't get much easier than that. Congratulations! 🍾

What's next?​

In the next post of this series, we'll be handling what happens when a user is away from a chat screen or offline. We'll be using in-app notifications to inform a user when a new message is received, or relevant action happens in a channel they've joined. We'll also be using Expo push notifications to inform users about new messages when they're not connected to your app and are offline. Stay tuned for more. 🔥

Like always, if you have any questions, comments or need help with any part of this article, join our Discord Server where you can ask questions, discuss what you're working on, and I'll be more than happy to help.

You can find the complete source code for this project inside this GitHub repository.

👉 Checkout the other blog posts in this series:

This article contains materials adapted from "Chat app with React Native" by Aman Mittal, originally published at Heartbeat.Fritz.Ai.

This article features an image by Volodymyr Hryshchenko.