Unlocking the Power of Streams in Modern Programming
The Evolution of Asynchronous Processing
In the early days of computing, applications were designed to run on local devices with no backend infrastructure. As a result, most operations were synchronous, causing the application to wait for commands or functions to complete. However, with the advent of APIs and remote data sources, this approach became unappealing. We couldn’t afford to lock up the UI for seconds at a time while waiting for data from an API.
The Rise of Streams
To address this challenge, modern programming languages and frameworks, such as Dart and Flutter, introduced constructs that enable efficient handling of streams. In this article, we’ll explore the concept of streams, how to work with StreamControllers, and how to use StreamBuilders in Flutter to update your UI.
Demystifying Streams
When I first started learning about streams, I was dazzled and confused. It’s not uncommon for developers to struggle with this concept, but trust me, it’s worth the effort. Streams are powerful tools that can simplify your code and improve performance. However, with great power comes great responsibility, and it’s essential to understand how to implement them correctly to avoid problems.
Understanding Synchronous and Asynchronous Methods
To grasp the concept of streams, let’s first revisit synchronous methods. These are straightforward, non-fancy methods that complete their function in a short time. We can then move on to asynchronous methods, which use the async and await keywords to retrieve data from various sources, such as APIs or file downloads.
The Limitations of Polling
While we can use async/await patterns to retrieve data, we’re still limited by the need to poll for updates. This approach is inefficient, as it puts the onus on the client device or app to check for changes. Instead, we can use streams to subscribe to updates and let the server notify us when something changes.
Working with Streams in Flutter
To illustrate the power of streams in Flutter, let’s create a simple app called flutter_streams that has a service with a StreamController. We’ll subscribe to updates from this StreamController to update the UI for our users. Our app will show us what cat is coming, going, and what state the cat is in when it does these things (meowing, content, or purring).
Laying the Groundwork
We’ll create our service at services/petservice.dart and define a list of cats to choose from. We’ll also set up an enum to define the various states our cat can be in and a Pet class to contain the name, color, and state of our pet.
Setting up the Stream
Next, we’ll create our PetService that exposes a StreamController for other parts of our app to listen to. We’ll set up a periodic timer that emits every three seconds into the StreamController when a pet either arrives or leaves.
Creating Our Flutter Stream Screen
We’ll create a StatefulWidget that subscribes to updates from our PetService. We’ll then use a StreamBuilder to react to changes in the stream and update our app’s screen accordingly.
Handling Stream Errors
Finally, we’ll discuss how to handle errors that may occur when working with streams. We’ll learn how to handle errors internally and capture them when a stream completes.
Recap and Conclusion
In conclusion, streams are a powerful tool for handling asynchronous data in modern programming. By understanding how to work with streams, you can simplify your code, improve performance, and create more efficient applications. With Flutter’s StreamBuilder, you can easily rebuild your widgets whenever it detects an update, making it easier to work with streams.