Add an empty state to the room list.

- Make `RoomListDataSource.allRooms` a `SharedFlow` so we can know when we don't have a value yet.
- Map its output in `RoomListPresenter` to `AsyncData`.
- Display the new empty state when the room list has loaded and has no items.

changelog.d/2330.feature

@@ -0,0 +1 @@
+Add empty state to the room list.

features/roomlist/impl/src/main/kotlin/io/element/android/features/roomlist/impl/RoomListPresenter.kt

@@ -23,6 +23,7 @@ import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.derivedStateOf
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.produceState
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.saveable.rememberSaveable
 import androidx.compose.runtime.setValue
@@ -32,6 +33,7 @@ import io.element.android.features.networkmonitor.api.NetworkMonitor
 import io.element.android.features.networkmonitor.api.NetworkStatus
 import io.element.android.features.roomlist.impl.datasource.InviteStateDataSource
 import io.element.android.features.roomlist.impl.datasource.RoomListDataSource
+import io.element.android.libraries.architecture.AsyncData
 import io.element.android.libraries.architecture.Presenter
 import io.element.android.libraries.designsystem.utils.snackbar.SnackbarDispatcher
 import io.element.android.libraries.designsystem.utils.snackbar.collectSnackbarMessageAsState
@@ -68,7 +70,9 @@ class RoomListPresenter @Inject constructor(
         val matrixUser: MutableState<MatrixUser?> = rememberSaveable {
             mutableStateOf(null)
         }
-        val roomList by roomListDataSource.allRooms.collectAsState()
+        val roomList by produceState(initialValue = AsyncData.Loading()) {
+            roomListDataSource.allRooms.collect { value = AsyncData.Success(it) }
+        }
         val filteredRoomList by roomListDataSource.filteredRooms.collectAsState()
         val filter by roomListDataSource.filter.collectAsState()
         val networkConnectionStatus by networkMonitor.connectivity.collectAsState()

features/roomlist/impl/src/main/kotlin/io/element/android/features/roomlist/impl/RoomListState.kt

@@ -19,6 +19,7 @@ package io.element.android.features.roomlist.impl
 import androidx.compose.runtime.Immutable
 import io.element.android.features.leaveroom.api.LeaveRoomState
 import io.element.android.features.roomlist.impl.model.RoomListRoomSummary
+import io.element.android.libraries.architecture.AsyncData
 import io.element.android.libraries.designsystem.utils.snackbar.SnackbarMessage
 import io.element.android.libraries.matrix.api.core.RoomId
 import io.element.android.libraries.matrix.api.user.MatrixUser
@@ -28,7 +29,7 @@ import kotlinx.collections.immutable.ImmutableList
 data class RoomListState(
     val matrixUser: MatrixUser?,
     val showAvatarIndicator: Boolean,
-    val roomList: ImmutableList<RoomListRoomSummary>,
+    val roomList: AsyncData<ImmutableList<RoomListRoomSummary>>,
     val filter: String?,
     val filteredRoomList: ImmutableList<RoomListRoomSummary>,
     val displayVerificationPrompt: Boolean,

features/roomlist/impl/src/main/kotlin/io/element/android/features/roomlist/impl/RoomListStateProvider.kt

@@ -20,6 +20,7 @@ import androidx.compose.ui.tooling.preview.PreviewParameterProvider
 import io.element.android.features.leaveroom.api.aLeaveRoomState
 import io.element.android.features.roomlist.impl.model.RoomListRoomSummary
 import io.element.android.features.roomlist.impl.model.aRoomListRoomSummary
+import io.element.android.libraries.architecture.AsyncData
 import io.element.android.libraries.designsystem.components.avatar.AvatarData
 import io.element.android.libraries.designsystem.components.avatar.AvatarSize
 import io.element.android.libraries.designsystem.utils.snackbar.SnackbarMessage
@@ -49,13 +50,15 @@ open class RoomListStateProvider : PreviewParameterProvider<RoomListState> {
                 )
             ),
             aRoomListState().copy(displayRecoveryKeyPrompt = true),
+            aRoomListState().copy(roomList = AsyncData.Success(persistentListOf())),
+            aRoomListState().copy(roomList = AsyncData.Loading()),
         )
 }
 
 internal fun aRoomListState() = RoomListState(
     matrixUser = MatrixUser(userId = UserId("@id:domain"), displayName = "User#1"),
     showAvatarIndicator = false,
-    roomList = aRoomListRoomSummaryList(),
+    roomList = AsyncData.Success(aRoomListRoomSummaryList()),
     filter = "filter",
     filteredRoomList = aRoomListRoomSummaryList(),
     hasNetworkConnection = true,

features/roomlist/impl/src/main/kotlin/io/element/android/features/roomlist/impl/RoomListView.kt

@@ -17,7 +17,9 @@
 package io.element.android.features.roomlist.impl
 
 import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Spacer
 import androidx.compose.foundation.layout.consumeWindowInsets
 import androidx.compose.foundation.layout.fillMaxSize
@@ -35,6 +37,7 @@ import androidx.compose.runtime.Composable
 import androidx.compose.runtime.derivedStateOf
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.remember
+import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.input.nestedscroll.NestedScrollConnection
 import androidx.compose.ui.input.nestedscroll.nestedScroll
@@ -42,6 +45,7 @@ import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.tooling.preview.PreviewParameter
 import androidx.compose.ui.unit.Velocity
 import androidx.compose.ui.unit.dp
+import io.element.android.compound.theme.ElementTheme
 import io.element.android.features.leaveroom.api.LeaveRoomView
 import io.element.android.features.networkmonitor.api.ui.ConnectivityIndicatorContainer
 import io.element.android.features.roomlist.impl.components.ConfirmRecoveryKeyBanner
@@ -51,17 +55,22 @@ import io.element.android.features.roomlist.impl.components.RoomListTopBar
 import io.element.android.features.roomlist.impl.components.RoomSummaryRow
 import io.element.android.features.roomlist.impl.model.RoomListRoomSummary
 import io.element.android.features.roomlist.impl.search.RoomListSearchResultView
+import io.element.android.libraries.architecture.AsyncData
 import io.element.android.libraries.designsystem.preview.ElementPreview
 import io.element.android.libraries.designsystem.preview.PreviewsDayNight
+import io.element.android.libraries.designsystem.theme.components.Button
 import io.element.android.libraries.designsystem.theme.components.FloatingActionButton
 import io.element.android.libraries.designsystem.theme.components.HorizontalDivider
 import io.element.android.libraries.designsystem.theme.components.Icon
+import io.element.android.libraries.designsystem.theme.components.IconSource
 import io.element.android.libraries.designsystem.theme.components.Scaffold
+import io.element.android.libraries.designsystem.theme.components.Text
 import io.element.android.libraries.designsystem.utils.CommonDrawables
 import io.element.android.libraries.designsystem.utils.LogCompositions
 import io.element.android.libraries.designsystem.utils.snackbar.SnackbarHost
 import io.element.android.libraries.designsystem.utils.snackbar.rememberSnackbarHostState
 import io.element.android.libraries.matrix.api.core.RoomId
+import io.element.android.libraries.ui.strings.CommonStrings
 
 @Composable
 fun RoomListView(
@@ -122,6 +131,35 @@ fun RoomListView(
     }
 }
 
+@Composable
+private fun EmptyRoomListView(
+    onCreateRoomClicked: () -> Unit,
+) {
+    Column(
+        modifier = Modifier.fillMaxSize(),
+        horizontalAlignment = Alignment.CenterHorizontally,
+        verticalArrangement = Arrangement.Center
+    ) {
+        Text(
+            text = stringResource(R.string.screen_roomlist_empty_title),
+            style = ElementTheme.typography.fontBodyLgRegular,
+            color = ElementTheme.colors.textSecondary,
+        )
+        Spacer(modifier = Modifier.height(4.dp))
+        Text(
+            text = stringResource(R.string.screen_roomlist_empty_message),
+            style = ElementTheme.typography.fontBodyLgRegular,
+            color = ElementTheme.colors.textSecondary,
+        )
+        Spacer(modifier = Modifier.height(16.dp))
+        Button(
+            text = stringResource(CommonStrings.action_start_chat),
+            leadingIcon = IconSource.Resource(CommonDrawables.ic_new_message),
+            onClick = onCreateRoomClicked,
+        )
+    }
+}
+
 @OptIn(ExperimentalMaterial3Api::class)
 @Composable
 private fun RoomListContent(
@@ -182,56 +220,62 @@ private fun RoomListContent(
             )
         },
         content = { padding ->
-            LazyColumn(
-                modifier = Modifier
-                    .padding(padding)
-                    .consumeWindowInsets(padding)
-                    .nestedScroll(nestedScrollConnection),
-                state = lazyListState,
-            ) {
-                when {
-                    state.displayVerificationPrompt -> {
-                        item {
-                            RequestVerificationHeader(
-                                onVerifyClicked = onVerifyClicked,
-                                onDismissClicked = { state.eventSink(RoomListEvents.DismissRequestVerificationPrompt) }
-                            )
+            println(state.roomList)
+            if (state.roomList is AsyncData.Success && state.roomList.data.isEmpty()) {
+                EmptyRoomListView(onCreateRoomClicked)
+            } else {
+                LazyColumn(
+                    modifier = Modifier
+                        .padding(padding)
+                        .consumeWindowInsets(padding)
+                        .nestedScroll(nestedScrollConnection),
+                    state = lazyListState,
+                ) {
+                    when {
+                        state.displayVerificationPrompt -> {
+                            item {
+                                RequestVerificationHeader(
+                                    onVerifyClicked = onVerifyClicked,
+                                    onDismissClicked = { state.eventSink(RoomListEvents.DismissRequestVerificationPrompt) }
+                                )
+                            }
+                        }
+                        state.displayRecoveryKeyPrompt -> {
+                            item {
+                                ConfirmRecoveryKeyBanner(
+                                    onContinueClicked = onOpenSettings,
+                                    onDismissClicked = { state.eventSink(RoomListEvents.DismissRecoveryKeyPrompt) }
+                                )
+                            }
                         }
                     }
-                    state.displayRecoveryKeyPrompt -> {
+
+                    if (state.invitesState != InvitesState.NoInvites) {
                         item {
-                            ConfirmRecoveryKeyBanner(
-                                onContinueClicked = onOpenSettings,
-                                onDismissClicked = { state.eventSink(RoomListEvents.DismissRecoveryKeyPrompt) }
-                            )
+                            InvitesEntryPointView(onInvitesClicked, state.invitesState)
                         }
                     }
-                }
 
-                if (state.invitesState != InvitesState.NoInvites) {
-                    item {
-                        InvitesEntryPointView(onInvitesClicked, state.invitesState)
+                    val roomList = state.roomList.dataOrNull().orEmpty()
+                    itemsIndexed(
+                        items = roomList,
+                        contentType = { _, room -> room.contentType() },
+                    ) { index, room ->
+                        RoomSummaryRow(
+                            room = room,
+                            onClick = ::onRoomClicked,
+                            onLongClick = onRoomLongClicked,
+                        )
+                        if (index != roomList.lastIndex) {
+                            HorizontalDivider()
+                        }
                     }
-                }
-
-                itemsIndexed(
-                    items = state.roomList,
-                    contentType = { _, room -> room.contentType() },
-                ) { index, room ->
-                    RoomSummaryRow(
-                        room = room,
-                        onClick = ::onRoomClicked,
-                        onLongClick = onRoomLongClicked,
-                    )
-                    if (index != state.roomList.lastIndex) {
-                        HorizontalDivider()
+                    // Add a last Spacer item to ensure that the FAB does not hide the last room item
+                    // FAB height is 56dp, bottom padding is 16dp, we add 8dp as extra margin -> 56+16+8 = 80
+                    item {
+                        Spacer(modifier = Modifier.height(80.dp))
                     }
                 }
-                // Add a last Spacer item to ensure that the FAB does not hide the last room item
-                // FAB height is 56dp, bottom padding is 16dp, we add 8dp as extra margin -> 56+16+8 = 80
-                item {
-                    Spacer(modifier = Modifier.height(80.dp))
-                }
             }
         },
         floatingActionButton = {

features/roomlist/impl/src/main/kotlin/io/element/android/features/roomlist/impl/datasource/RoomListDataSource.kt

@@ -28,7 +28,9 @@ import kotlinx.collections.immutable.persistentListOf
 import kotlinx.collections.immutable.toImmutableList
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.FlowPreview
+import kotlinx.coroutines.flow.MutableSharedFlow
 import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.SharedFlow
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.combine
 import kotlinx.coroutines.flow.debounce
@@ -52,7 +54,7 @@ class RoomListDataSource @Inject constructor(
     }
 
     private val _filter = MutableStateFlow("")
-    private val _allRooms = MutableStateFlow<ImmutableList<RoomListRoomSummary>>(persistentListOf())
+    private val _allRooms = MutableSharedFlow<ImmutableList<RoomListRoomSummary>>(replay = 1)
     private val _filteredRooms = MutableStateFlow<ImmutableList<RoomListRoomSummary>>(persistentListOf())
 
     private val lock = Mutex()
@@ -90,7 +92,7 @@ class RoomListDataSource @Inject constructor(
     }
 
     val filter: StateFlow<String> = _filter
-    val allRooms: StateFlow<ImmutableList<RoomListRoomSummary>> = _allRooms
+    val allRooms: SharedFlow<ImmutableList<RoomListRoomSummary>> = _allRooms
     val filteredRooms: StateFlow<ImmutableList<RoomListRoomSummary>> = _filteredRooms
 
     @OptIn(FlowPreview::class)

features/roomlist/impl/src/test/kotlin/io/element/android/features/roomlist/impl/RoomListPresenterTests.kt

@@ -166,14 +166,16 @@ class RoomListPresenterTests {
         moleculeFlow(RecompositionMode.Immediate) {
             presenter.present()
         }.test {
-            val initialState = consumeItemsUntilPredicate { state -> state.roomList.size == 16 }.last()
+            val initialState = consumeItemsUntilPredicate { state -> state.roomList.dataOrNull()?.size == 16 }.last()
             // Room list is loaded with 16 placeholders
-            assertThat(initialState.roomList.size).isEqualTo(16)
-            assertThat(initialState.roomList.all { it.isPlaceholder }).isTrue()
+            val initialItems = initialState.roomList.dataOrNull().orEmpty()
+            assertThat(initialItems.size).isEqualTo(16)
+            assertThat(initialItems.all { it.isPlaceholder }).isTrue()
             roomListService.postAllRooms(listOf(aRoomSummaryFilled()))
-            val withRoomState = consumeItemsUntilPredicate { state -> state.roomList.size == 1 }.last()
-            assertThat(withRoomState.roomList.size).isEqualTo(1)
-            assertThat(withRoomState.roomList.first())
+            val withRoomState = consumeItemsUntilPredicate { state -> state.roomList.dataOrNull()?.size == 1 }.last()
+            val withRoomStateItems = withRoomState.roomList.dataOrNull().orEmpty()
+            assertThat(withRoomStateItems.size).isEqualTo(1)
+            assertThat(withRoomStateItems.first())
                 .isEqualTo(aRoomListRoomSummary)
             scope.cancel()
         }
@@ -194,7 +196,7 @@ class RoomListPresenterTests {
             skipItems(3)
             val loadedState = awaitItem()
             // Test filtering with result
-            assertThat(loadedState.roomList.size).isEqualTo(1)
+            assertThat(loadedState.roomList.dataOrNull().orEmpty().size).isEqualTo(1)
             loadedState.eventSink.invoke(RoomListEvents.UpdateFilter(A_ROOM_NAME.substring(0, 3)))
             skipItems(1)
             val withFilteredRoomState = awaitItem()
@@ -384,10 +386,10 @@ class RoomListPresenterTests {
             notificationSettingsService.setRoomNotificationMode(A_ROOM_ID, userDefinedMode)
 
             val updatedState = consumeItemsUntilPredicate { state ->
-                state.roomList.any { it.id == A_ROOM_ID.value && it.userDefinedNotificationMode == userDefinedMode }
+                state.roomList.dataOrNull().orEmpty().any { it.id == A_ROOM_ID.value && it.userDefinedNotificationMode == userDefinedMode }
             }.last()
 
-            val room = updatedState.roomList.find { it.id == A_ROOM_ID.value }
+            val room = updatedState.roomList.dataOrNull()?.find { it.id == A_ROOM_ID.value }
             assertThat(room?.userDefinedNotificationMode).isEqualTo(userDefinedMode)
             cancelAndIgnoreRemainingEvents()
             scope.cancel()