Build Awesome Chat App using MVVM with Stream - Part 1

Table of Contents

1. Introduction
2. What is Stream SDK?
3. The Power of Stream SDK
4. Setting up the Chat Application
5. Creating a Login Fragment
6. Implementing Login View Model
7. Handling UI States in Login Fragment
8. Sending Events with Shared Flow
9. Catching Events in Login Fragment
10. Testing the Login Functionality

Introduction

In this tutorial, we will be building a chat application using the Stream SDK. Stream SDK is an SDK that simplifies the process of building chat applications by providing all the necessary views and backend functionality. With Stream SDK, You can fully customize your chat app and Create both simple and complex chat applications. Throughout this tutorial, we will cover the installation process, creating login functionality, handling UI states, sending and catching events, and testing the login functionality.

1. What is Stream SDK?

Stream SDK is an SDK that makes it super easy to build chat applications. It provides all the necessary views and backend functionality for creating fully working chat apps. Stream SDK is often compared to Firebase for chat apps, but it also offers a lot of customization options and control over your app.

2. The Power of Stream SDK

With Stream SDK, you can create chat applications of any complexity. Whether it's a one-to-one chat or a group chat with specified people, Stream SDK has got you covered. It offers features like sending messages, attachments, and using Instant commands. You can also create custom views and customize your chat app using Stream UI properties.

3. Setting up the Chat Application

Before we start implementing the chat application, there are a few prerequisites. First, you need to create an account on getstream.io, the official Website of Stream SDK. It's important to note that if you only use Stream SDK for hobby projects, you can use the Maker account, which is free for small team sizes and hobby projects. Once you have created an account, you will receive an API key that is required for setting up the chat application.

4. Creating a Login Fragment

The first step in building our chat application is creating a login fragment. This fragment will be responsible for user authentication and login functionality. We will validate the entered username and connect the user using the Stream SDK's chat client. If any errors occur during the login process, we will display an error message.

5. Implementing Login View Model

To handle the business logic of the login fragment, we will create a login view model. The view model will communicate with the chat client to connect the user and handle the login process. It will also provide events and error messages to the login fragment.

6. Handling UI States in Login Fragment

In the login fragment, we will handle different UI states Based on the login process. When the user clicks the confirm button, we will Show a progress bar and disable the button to prevent multiple login attempts. Once the login process is complete, we will reset the UI to its original state.

7. Sending Events with Shared Flow

To send events from the view model to the fragment, we will be using a shared flow. Shared flow is a flow Type that emits events. We will define different types of events, such as successful login, input too short, and login error. These events will be emitted based on the login process.

8. Catching Events in Login Fragment

In the login fragment, we will observe the shared flow and catch the emitted events. Depending on the event type, we will display Relevant messages to the user. For example, if the username input is too short, we will display an error message. If the login is successful, we will navigate to the next screen.

9. Testing the Login Functionality

To test the login functionality, we will run the chat application on a device or emulator. We will enter valid and invalid usernames to check the validation and error handling process. We will also test the login process in different network conditions, such as with and without internet connectivity.

Article

Introduction

Building a chat application from scratch can be a complex and time-consuming task. However, with the Stream SDK, the process becomes incredibly easy and efficient. In this tutorial, we will explore the power of Stream SDK and learn how to build a fully functional chat application. We will cover topics such as setting up the chat application, creating a login fragment, implementing the login view model, handling UI states, and sending events using shared flow.

What is Stream SDK?

Stream SDK is a powerful software development kit that simplifies the process of building chat applications. It provides all the necessary tools and resources for creating fully working chat apps, including views and backend functionality. Stream SDK can be compared to Firebase for chat apps, but it offers a higher level of customization and control over your application.

The Power of Stream SDK

What sets Stream SDK apart is its ability to handle chat applications of any complexity. Whether you need a simple one-to-one chat or a group chat with specified people, Stream SDK has got you covered. It offers features like sending messages, attachments, and using instant commands. You can fully customize your chat app using Stream UI properties and even create custom views for a unique user experience.

Setting up the Chat Application

Before we dive into creating the chat application, there are a few prerequisites that need to be completed. The first step is to create an account on getstream.io, the official website of Stream SDK. Once you have created an account, you will receive an API key that is required for setting up the chat application. It's important to note that if you only use Stream SDK for hobby projects, you can use the Maker account, which is free for small team sizes and hobby projects.

Creating a Login Fragment

The login fragment is the starting point of our chat application. It is responsible for user authentication and login functionality. In this fragment, users will be able to enter their username and click a confirm button to initiate the login process. We will validate the entered username and connect the user using the Stream SDK's chat client. If any errors occur during the login process, we will display an appropriate error message to the user.

Implementing Login View Model

To handle the business logic of the login fragment, we will create a login view model. View models are an essential part of the MVVM (Model-View-ViewModel) architecture pattern. In this view model, we will communicate with the chat client to connect the user and handle the login process. We will also provide events and error messages to the login fragment for displaying UI changes and handling errors.

Handling UI States in Login Fragment

UI states play a crucial role in providing a smooth user experience. In the login fragment, we will handle different UI states based on the login process. When the user clicks the confirm button, we will show a progress bar and disable the button to prevent multiple login attempts. Once the login process is complete, we will reset the UI to its original state using the view model's state variables.

Sending Events with Shared Flow

To send events from the view model to the fragment, we will be using a shared flow. Shared flow is a powerful Kotlin feature that allows us to emit events from one source and Collect them in multiple destinations. We will define different types of events, such as successful login, input too short, and login error, and emit them using the shared flow. The login fragment will observe this shared flow and react accordingly.

Catching Events in Login Fragment

In the login fragment, we will observe the shared flow and catch the emitted events. Depending on the event type, we will display relevant messages to the user. For example, if the username input is too short, we will display an error message stating the minimum required length. If the login is successful, we will navigate the user to the next screen or perform any other desired actions.

Testing the Login Functionality

To ensure the reliability and functionality of our chat application, it's essential to thoroughly test the login process. We will run the chat application on a device or emulator and enter valid and invalid usernames to test the validation and error handling process. Additionally, we will test the login functionality under different network conditions, such as with and without internet connectivity, to ensure its robustness.

Highlights

• Stream SDK simplifies the process of building chat applications.
• It provides all the necessary views and backend functionality.
• Stream SDK offers customization options and control over your chat app.
• Setting up Stream SDK requires creating an account on getstream.io.
• Creating a login fragment is the first step in building the chat application.
• The login view model handles the business logic of the login fragment.
• Handling UI states in the login fragment provides a smooth user experience.
• Using shared flow enables us to send events from the view model to the fragment.
• Catching events in the login fragment allows us to display relevant messages and react accordingly.
• Thoroughly testing the login functionality ensures the reliability of the chat application.

FAQ

Q: Can I customize the UI of the chat application? A: Yes, Stream SDK provides extensive customization options. You can customize the chat views using Stream UI properties and even create custom views for a unique user experience.

Q: How do I handle errors during the login process? A: In the login view model, you can catch the errors from the Stream SDK's chat client and emit an error event using shared flow. The login fragment can then display the error message to the user.

Q: Can I use Stream SDK for both one-to-one and group chats? A: Yes, Stream SDK supports both one-to-one and group chats. You can create group chats with specified people or have one-to-one chats with individual users.

Q: Is Stream SDK suitable for hobby projects? A: Yes, Stream SDK offers a Maker account that is free for small team sizes and hobby projects. You can use it without any cost if you fulfill the eligibility criteria.

Q: How can I test the login functionality in different network conditions? A: To test the login functionality under different network conditions, you can run the chat application on a device or emulator and switch the network settings to simulate different scenarios, such as with and without internet connectivity.