How to Build a Chat Application in Android

7 min read Oliver Carson on Feb 20, 2024
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Mobile chat applications are an effective way to create digital environments where people and devices around the world can easily collaborate, socialize, make new experiences, and exchange information in real time. The world’s most popular operating system powering these devices is Android, an open-source mobile platform where developers can create various applications for phones, watches, televisions, and cars. Google originally developed the Android platform in 2008 and currently powers more than 2.5 billion devices worldwide.

Among the most popular mobile apps used by devices are chat applications. Users depend on social applications such as WhatsApp, Snapchat, Messenger, Discord, Zoom, and Slack to interact with others across the world with text messages, SMS messages, and video calls, all in real time. In an ever-increasing need for virtual spaces, professionals, students, and everyday users need to stay connected to their school, business, healthcare, friends, and families no matter where they are in the world. Continue reading to learn more about the Android platform, why developers should create chat applications for these mobile devices, and the steps necessary to create chat apps in Android.

Why build chat applications in Android

Android is a mobile platform that allows users to create applications for phones, tablets, smartwatches, televisions, and cars. Android is open-source, which allows the advancement of more feature-rich devices and applications. Being an open-source platform helps every persona:

  • Manufacturers other than Google can produce phones that rely on the Android operating system, allowing for a lot of variety in the market. 

  • Developers can experiment with different Android functionality that suits their application needs and collaborate with others on GitHub to continue developing new features.

  • Consumers can purchase competitively priced phones that allow them flexibility based on their budget.

Google offers developer resources that allow developers to fully experiment with Android functionality, with most features being initially free when getting started. Sync up with Google services, such as Firebase, to store, manage, perform authentication requests, and send mobile push notifications to your devices via Firebase Cloud Messaging. Google Maps provides a Map API to add GPS functionality to your application and Google Play allows you to distribute your application as well as host in-app services such as purchases, news updates, social features, accessibility functions, analytics, and more. There is a plethora of learning resources available offered by both Google and community members that guides users through integrating these services into their applications.

By making use of these services, your Android chat application can fully serve the needs of your user base. You can host back-end services that support the logic of your application using Firebase. Google Maps can provide location details of posts/profile information for your users. Google Play provides distribution and other in-app purchases, such as premium plan upgrades or valuable extensions from other apps in the Play Store. You can also make use of Google Play for analytical data and other social features your application can take advantage of.

How to build Android chat applications

To begin building your chat application in Android, download Android Studio, the official Integrated Development Environment (IDE) for Android app development.

Once you’ve downloaded the latest version of Android Studio, create a project that targets the platform of choice. You can run emulated environments of various devices, including mobile phones, tablets, watches, televisions, and cars. You’ll need to then select your language of choice. Android offers two languages, Java and Kotlin. While Java has been the standard of Android development for many years, Android now recommends using Kotlin to build your Android applications, as it provides more stability and feature-rich language features in Android apps. Give your Android application a package name and press the create button to initialize your new messaging app and begin development in the MainActivity class. Follow Android’s getting started guides and integrate Google services to solve common problems for your Android app by following along with Google’s Codelabs Tutorials. Be sure to also take advantage of toolkits such as Jetpack Compose, the recommended toolkit for building native UI efficiently, by using the androidx namespace (instead of historically using XML to layout the UI), Be sure to also install any community-recommended plugins to aid in your development process.

As you build your application, you’ll need to keep in mind the different types of interactions and features your users require. Users will want to be able to join different servers or organizations that are uniquely created for their hobbies or professional use. They will want to be able to collaborate on different channels or topics, as well as be able to have group chats or even 1:1 conversations with friends and coworkers in private chat rooms. Users should be able to access a member list that shows if their friends or channel members are online. When typing messages, users should be able to see when others are typing or responding and allow for message reactions and emoji support to keep conversations lively. Mobile push notifications should be used to alert users of new messages at the top of the screen and in the app icon or widget from other users while they are elsewhere in the chat app, the chat app is in the background, or have completely closed the application.

Powering these features is by no means an easy task. You have to set up an infrastructure to maintain the communication platform that handles the exchange of messages between all users, detect an online presence system, load messages when users come online, and maintain, as well as scale, these features securely for your users, on top of building the UI for your chat app. While it is possible to build this infrastructure yourself, this will take time, resources, and upkeep that can be spent elsewhere. This is where PubNub can help.

Android chat examples

Android apps that contain in-app messaging such as WhatsApp, Messenger, Snapchat, Discord, and Slack use their own implementation of these features in their apps to create unique experiences for users. However, with PubNub, companies don’t have to set up the infrastructure that needs to reliably scale and minimize latency, no matter the size of its users.

NurseGrid, an app that allows nursing departments to access, manage, and share their schedules with colleagues in real time, uses PubNub to power real-time scheduling updates with mobile push notifications and in-app messaging, helping to reduce inefficiencies in nurse scheduling.

Josh Talks, an English learning platform in India, uses PubNub to power direct and group chat at scale, as well as mobile push notifications, increasing time spent in-app and customer retention. With over five million downloads in the Play Store, PubNub eliminates concurrency and latency issues the developers of Josh Talks were facing and helps optimize the platform to better serve users across different locations, languages, and devices in real time.

vFairs is a virtual events platform that allows companies and organizations of any size to create engaging, seamless remote experiences that connect people globally, whether for an audience of 50 or 30,000. vFairs uses PubNub to provide reliable and scalable in-app chat in real time to these audience members and has saved 75% in developer time by moving from their in-house chat to PubNub.

Getting Started with PubNub for your Android chat app

PubNub is a developer API platform that enables applications to receive real-time updates at a massive, global scale. PubNub serves as the foundation for over 2000 customers in diverse industries. Developers can depend on PubNub’s scalability and reliability to power chat features for their applications by making use of different chat SDKs. PubNub is efficient, reliable, and fast enough to power these features in real-time chat applications, without affecting the user experience.

PubNub has the following features built-in to its API and can meet the specific needs of your application.

  1. Publish: Send messages whenever user input is updated, such as text updates, emoji reactions, sent files, and other complex metadata.

  2. Subscribe: Receive new messages to refresh users' screens.

  3. Presence: Update and detect the online status of users.

  4. Message Persistence: Display any received messages once users login to the app or track project and document revisions.

  5. Mobile Push Notifications: Notify mobile users who are away from the app about any chat messages, project updates, or application updates.

  6. App Context: Store information about your user in one place without the need of setting up or calling your database.

  7. Access Manager: Restrict access for private conversations, channel rooms, documents, and projects for specific users.

  8. Functions: Translate messages, censor inappropriate messages, announce the arrival of new users, and notify other users of mentions.

  9. Events & Actions: Centrally manage events in your application’s ecosystem and trigger business logic with no code.

To begin using PubNub to power your Android real-time chat app, you’ll need to first create a PubNub account and download PubNub’s Android SDK. The SDK integrates seamlessly into your application and allows you to connect to PubNub’s real-time communication platform.

  1. Sign in or create an account to create an app on the Admin Portal and get the keys to use in your application. Learn how to do so by following this how-to on creating keys.

  2. Download the Android SDK by following the instructions in the documentation to install any necessary PubNub dependencies for your messaging app.

  3. Follow the SDK’s getting started documentation to configure your keys in the build.gradle file and begin implementing the features to drive your chat functionality.

To learn more: We have a tutorial dedicated to building a simple Android chat application using our Kotlin SDK.

If you would like more personal assistance, please reach out to us. We’ll walk you through the best way to add PubNub to your Android chat application.