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Lazily load list #350

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Merged
merged 8 commits into from
Sep 30, 2024
Merged

Lazily load list #350

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8325a2c
Code snippet for Compose doc at https://developer.android.com/quick-g…
thedmail Sep 17, 2024
ccf9d11
Adds empty Modifiers to function signatures that had no Modifiers bef…
thedmail Sep 17, 2024
a9bbe00
Apply Spotless
thedmail Sep 17, 2024
65fb7b5
Corrects region tags for includecode widget.
thedmail Sep 23, 2024
bd71f12
Merge remote-tracking branch 'origin/lazily-load-list' into lazily-lo…
thedmail Sep 23, 2024
f1ba73a
Added sender and text to Message class.
riggaroo Sep 27, 2024
13a1642
Merge branch 'main' into lazily-load-list
riggaroo Sep 27, 2024
4b1c549
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riggaroo Sep 27, 2024
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55 changes: 54 additions & 1 deletion compose/snippets/src/main/java/com/example/compose/snippets/lists/LazyListSnippets.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -33,6 +33,7 @@ import androidx.compose.foundation.layout.Row
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.foundation.layout.fillMaxWidth
import androidx.compose.foundation.layout.height
import androidx.compose.foundation.layout.padding
import androidx.compose.foundation.layout.size
import androidx.compose.foundation.layout.width
import androidx.compose.foundation.layout.wrapContentHeight
Expand All @@ -52,6 +53,8 @@ import androidx.compose.foundation.lazy.staggeredgrid.items
import androidx.compose.foundation.rememberScrollState
import androidx.compose.foundation.verticalScroll
import androidx.compose.material3.Button
import androidx.compose.material3.Card
import androidx.compose.material3.CircularProgressIndicator
import androidx.compose.material3.Text
import androidx.compose.runtime.Composable
import androidx.compose.runtime.LaunchedEffect
Expand All @@ -78,6 +81,7 @@ import kotlinx.coroutines.flow.distinctUntilChanged
import kotlinx.coroutines.flow.filter
import kotlinx.coroutines.flow.map
import kotlinx.coroutines.launch
import org.w3c.dom.Text

private object ListsSnippetsColumn {
// [START android_compose_layouts_list_column]
Expand Down Expand Up @@ -684,7 +688,7 @@ fun LazyStaggeredGridSnippetFixed() {
)
// [END android_compose_layouts_lazy_staggered_grid_fixed]
}
private class Message(val id: Long)
class Message(val id: Long, val sender: String, val text: String)
private class Item

private data class Contact(val firstName: String)
Expand Down Expand Up @@ -752,6 +756,55 @@ private val randomSizedPhotos = listOf(
randomSampleImageUrl(width = 1600, height = 900),
randomSampleImageUrl(width = 500, height = 500),
)
// [START android_compose_layouts_lazily_load_list]
@Composable
fun MessageList(
modifier: Modifier,
pager: Pager<Int, Message>
) {
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)
}
}
}
}
// [END android_compose_layouts_lazily_load_list]

// [START android_compose_lists_snap_scroll_button]
@Composable
Expand Down