🖐 Hello everyone!

Today, we’re going to talk about a common issue in Android app development: Side Effects.

Side effects often go unnoticed, yet they can have a significant impact on user experience and app performance. In this article, we’ll explore what side effects are in the context of Android applications, when and why they occur, and most importantly, how to effectively handle them in your projects.

What Are Side Effects?
Side effects refer to operations performed by a Composable function that go beyond its primary responsibility of generating UI. While a Composable is mainly expected to render the UI, it might also perform additional actions such as writing to a database, making API calls, reading/writing files, displaying a Snackbar message, logging, and so on. These kinds of operations are considered side effects because they involve interaction with the application’s state or the outside world.

Such effects must be managed in a way that aligns with the declarative and reactive nature of Jetpack Compose. Otherwise, it can lead to performance issues, unexpected behavior, and potentially memory leaks — ultimately harming the user experience.

We need to manage these effects correctly in order to enhance user experience and optimize application performance. Otherwise, we might encounter lags, freezes, or other undesirable behavior, which is something we definitely want to avoid. This is exactly where Effect Handlers come into play — they provide a structured way to handle side effects more effectively.

What Are Effect Handlers?
Jetpack Compose provides various Effect Handlers to manage side effects in a safe and efficient way. Without using these structures, side effects could block the UI thread, which would severely impact application performance and the overall user experience.

LaunchedEffect
LaunchedEffect is used for asynchronous operations that need to run either once or under specific conditions, depending on the lifecycle of a Composable. Since LaunchedEffect is a Composable function, it can only be used within other Composable functions. It utilizes suspend functions to perform its operations and works seamlessly with coroutines. It can take one or more key parameters, and it gets triggered either when the Composable is first composed or when any of the provided keys change.

LaunchedEffect function

To help better understand how LaunchedEffect works, I’ve shared an example on my GitHub account.
For those who are interested, feel free to check it out here:

rememberCoroutineScope
rememberCoroutineScope is used to create a coroutine scope that is tied to the lifecycle of a Composable. This means that if the associated Composable is removed from the composition—such as during a screen transition or recomposition—the created coroutine scope is automatically cancelled. This behavior contributes to performance optimization by preventing unnecessary resource usage.

When you need to launch a coroutine from an event handler — such as inside a button’s onClick block—rather than directly within the body of a Composable function, you should use rememberCoroutineScope instead of LaunchedEffect.

rememberCoroutineScope yapısı

rememberUpdatedState

In LaunchedEffect, the effect is re-executed whenever the provided keys change. However, there are cases where we don’t want the coroutine to restart even if some values used inside the effect change. In such situations, we should use rememberUpdatedState.

rememberUpdatedState yapısı

DisposableEffect
Some side effects need to be cleaned up when they are no longer needed. For example:

• If you’ve registered a listener (observer), you should remove it when it’s no longer necessary.
• If you’ve added a BroadcastReceiver, you should unregister it when it’s not being used.
• If you’ve opened a resource (such as a socket connection), you should close it when exiting.

In such cases, DisposableEffect should be used to handle both the setup and the cleanup of the effect. It provides a safe way to manage external resources within the lifecycle of a Composable.

SideEffect
SideEffect is used to send data or updates to objects not managed by Compose. It runs after every successful composition or recomposition.
This is useful when you need to synchronize Compose-managed state with external systems that are not part of the Compose UI hierarchy.

Conclusion

Properly managing side effects in Jetpack Compose is essential for the performance, reliability, and overall user experience of your application. Tools like LaunchedEffect, rememberCoroutineScope, rememberUpdatedState, DisposableEffect, and SideEffect allow us to handle side effects in a way that aligns with Compose’s reactive and declarative nature.

Each of these effect handlers serves a specific purpose and helps keep your code clean, efficient, and maintainable. As your app grows in size and complexity, using these tools correctly will make debugging easier and provide a smoother experience for your users.

Remember, Compose is not just about drawing UI — it also brings a set of powerful mechanisms that every modern Android developer should understand and use effectively.

Source

Thanks for reading! See you in future posts.

References

This article was previously published on proandroiddev.com.