Implement Pull-to-Refresh in Jetpack Compose Lists Easily

Pull-to-refresh is a widely used UX pattern that allows users to refresh data in lists or other scrollable content. With the advent of Jetpack Compose, Google’s modern UI toolkit, implementing this feature has become significantly easier and more declarative. In this blog post, we’ll explore how to implement pull-to-refresh in Jetpack Compose lists, focusing on best practices, advanced use cases, and leveraging Compose’s capabilities for a seamless developer experience.

Why Jetpack Compose Makes Pull-to-Refresh Simpler

Jetpack Compose replaces traditional XML-based UI development with a Kotlin-based declarative approach, reducing boilerplate code and making UI updates more intuitive. When implementing features like pull-to-refresh, Compose’s state management and integration with Kotlin coroutines make it incredibly straightforward to manage UI interactions and asynchronous data fetching.

Setting Up Your Project for Jetpack Compose

Before we dive into the implementation, ensure your project is configured for Jetpack Compose. Here are the key dependencies you’ll need in your build.gradle file:

android {
    compileSdk 33
    defaultConfig {
        minSdk 21
        targetSdk 33
    }
    buildFeatures {
        compose true
    }
    composeOptions {
        kotlinCompilerExtensionVersion "1.5.3"
    }
}

dependencies {
    implementation "androidx.compose.ui:ui:1.5.0"
    implementation "androidx.compose.material:material:1.5.0"
    implementation "androidx.compose.ui:ui-tooling:1.5.0"
    implementation "androidx.lifecycle:lifecycle-runtime-compose:2.6.1"
    implementation "androidx.activity:activity-compose:1.7.2"
}

Once your project is set up, you’re ready to implement pull-to-refresh functionality.

Implementing Pull-to-Refresh in Jetpack Compose

The simplest way to implement pull-to-refresh in Jetpack Compose is by using SwipeRefresh from the accompanist library. Here’s a step-by-step guide:

Step 1: Add the Accompanist Library

First, add the accompanist dependency for swipe refresh to your project:

dependencies {
    implementation "com.google.accompanist:accompanist-swiperefresh:0.31.2-alpha"
}

Step 2: Build a Basic List

Start with a simple Compose list. Use LazyColumn, which is ideal for displaying large data sets efficiently.

@Composable
fun SimpleList(items: List<String>) {
    LazyColumn {
        items(items) { item ->
            Text(
                text = item,
                modifier = Modifier
                    .fillMaxWidth()
                    .padding(16.dp),
                style = MaterialTheme.typography.body1
            )
        }
    }
}

Step 3: Integrate Swipe-to-Refresh

Wrap the LazyColumn with SwipeRefresh to add pull-to-refresh functionality. You’ll need to manage the refresh state using remember or other state management techniques.

@Composable
fun RefreshableList(items: List<String>, onRefresh: () -> Unit, isRefreshing: Boolean) {
    SwipeRefresh(
        state = rememberSwipeRefreshState(isRefreshing),
        onRefresh = onRefresh
    ) {
        LazyColumn {
            items(items) { item ->
                Text(
                    text = item,
                    modifier = Modifier
                        .fillMaxWidth()
                        .padding(16.dp),
                    style = MaterialTheme.typography.body1
                )
            }
        }
    }
}

Step 4: Handle Refresh Logic

In your @Composable function, manage the refresh state and data updates using remember and LaunchedEffect.

@Composable
fun RefreshableScreen() {
    val items = remember { mutableStateOf(listOf("Item 1", "Item 2", "Item 3")) }
    val isRefreshing = remember { mutableStateOf(false) }

    fun refreshData() {
        isRefreshing.value = true
        // Simulate a data fetch
        CoroutineScope(Dispatchers.IO).launch {
            delay(2000) // Simulate network delay
            items.value = listOf("New Item 1", "New Item 2", "New Item 3")
            isRefreshing.value = false
        }
    }

    RefreshableList(
        items = items.value,
        onRefresh = { refreshData() },
        isRefreshing = isRefreshing.value
    )
}

Advanced Use Cases

1. Combining Pull-to-Refresh with Paging

For large datasets, integrate pull-to-refresh with the Jetpack Paging library to efficiently load and display paginated data. Replace the static list with a LazyPagingItems object.

val pagingItems = pager.collectAsLazyPagingItems()

SwipeRefresh(
    state = rememberSwipeRefreshState(isRefreshing),
    onRefresh = { refreshData() }
) {
    LazyColumn {
        items(pagingItems) { item ->
            // Render item
        }
    }
}

2. Custom Refresh Indicators

You can customize the refresh indicator to better match your app’s branding by using the indicator parameter of SwipeRefresh.

SwipeRefresh(
    state = rememberSwipeRefreshState(isRefreshing),
    onRefresh = onRefresh,
    indicator = { state, trigger ->
        CircularProgressIndicator(
            modifier = Modifier.padding(16.dp)
        )
    }
) {
    // Content
}

Best Practices for Pull-to-Refresh

  1. Avoid Overuse: Pull-to-refresh is most effective for real-time data like news feeds or email clients. Avoid using it for static or infrequently updated content.

  2. Provide Feedback: Always show a loading spinner or indicator to inform users that their refresh action is in progress.

  3. Optimize Data Fetching: Ensure that the data-fetching logic is efficient and does not result in unnecessary network calls.

  4. Handle Errors Gracefully: If data fetching fails, notify users with a retry option or appropriate error message.

  5. Test Responsively: Ensure your implementation works well across different screen sizes and orientations.

Conclusion

Implementing pull-to-refresh in Jetpack Compose is not only straightforward but also highly customizable. By leveraging SwipeRefresh and Compose’s declarative paradigm, you can create responsive and engaging user experiences with minimal boilerplate code. Whether you’re working with static lists or dynamic paginated content, Compose provides the flexibility to meet your app’s needs.

By following the techniques and best practices discussed in this post, you’ll be well-equipped to implement pull-to-refresh functionality effectively in your Jetpack Compose projects.

Happy coding!