With lazy loading and Paging, you can support large lists of items---including an
infinite list---in your app by loading and displaying data incrementally. This
technique enables you to reduce initial load times and optimize memory usage,
enhancing performance.
> [!NOTE]
> **Note:** For optimized performance, use the Paging Library with a lazy list for an infinite list of data.
## Results
The following video shows the resulting behavior of a large list fetching data
as the user scrolls.
## Version compatibility
This implementation requires that your project minSDK be set to API level 21 or
higher.
### Dependencies
## Display paged content
With the Paging library, you can load and display pages of data from a larger
dataset acquired from local storage or over a network. Use the following code to
display a paginated list that shows a progress bar to indicate to the user that
more data is being fetched:
```kotlin
@Composable
fun MessageList(
modifier: Modifier,
pager: Pager
) {
val lazyPagingItems = pager.flow.collectAsLazyPagingItems()
LazyColumn {
items(
lazyPagingItems.itemCount,
key = lazyPagingItems.itemKey { it.id }
) { index ->
val message = lazyPagingItems[index]
if (message != null) {
MessageRow(message)
} else {
MessagePlaceholder()
}
}
}
@Composable
fun MessagePlaceholder(modifier: Modifier) {
Box(
Modifier
.fillMaxWidth()
.height(48.dp)
) {
CircularProgressIndicator()
}
}
@Composable
fun MessageRow(
modifier: Modifier,
message: Message
) {
Card(modifier = Modifier.padding(8.dp)) {
Column(
modifier = Modifier.padding(8.dp),
verticalArrangement = Arrangement.Center
) {
Text(message.sender)
Text(message.text)
}
}
}
}
```
### Key points about the code
- [`LazyColumn`](https://developer.android.com/reference/kotlin/androidx/compose/foundation/lazy/LazyColumn.composable.md.txt): This composable is used to display a large list of items (messages) efficiently. It only renders the items that are visible on the screen, thus saving resources and memory.
- The [`lazyPagingItems`](https://developer.android.com/reference/kotlin/androidx/paging/compose/LazyPagingItems.md.txt) object efficiently manages the loading and presentation of paged data within the `LazyColumn`. It passes `LazyPagingItems` to [`items`](https://developer.android.com/reference/kotlin/androidx/compose/foundation/lazy/LazyListScope.md.txt#items(kotlin.Int,kotlin.Function1,kotlin.Function1,kotlin.Function2)) in the `LazyColumn` composable.
- `MessageRow(message: Text)` is responsible for rendering individual message items, likely displaying the sender and text of the message within a Card.
- `MessagePlaceholder()` provides a visual placeholder (a loading spinner) while the actual message data is being fetched, enhancing the user experience.
## Collections that contain this guide
This guide is part of these curated Quick Guide collections that cover
broader Android development goals:
 
### Display a list or grid
Lists and grids allow your app to display collections in a visually pleasing form that's easy for users to consume. [Quick guide collection](https://developer.android.com/develop/ui/compose/quick-guides/collections/display-a-list-or-grid)  
### Display interactive components
Learn how composable functions can enable you to easily create beautiful UI components based on the Material Design design system. [Quick guide collection](https://developer.android.com/develop/ui/compose/quick-guides/collections/display-interactive-components)  
### Compose basics (video collection)
This series of videos introduces various Compose APIs, quickly showing you what's available and how to use them. [Quick guide collection](https://developer.android.com/develop/ui/compose/quick-guides/collections/compose-basics) 
## Have questions or feedback
Go to our frequently asked questions page and learn about quick guides or reach out and let us know your thoughts. [Go to FAQ](https://developer.android.com/quick-guides/faq.md.txt) [Leave feedback](https://issuetracker.google.com/issues/new?component=1573691&template=1993320)