design(home) : allow scrolling to top when clicking on already selected tab

features/home/impl/src/main/kotlin/io/element/android/features/home/impl/HomeView.kt

@@ -18,6 +18,7 @@ import androidx.compose.foundation.layout.calculateStartPadding
 import androidx.compose.foundation.layout.consumeWindowInsets
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.lazy.rememberLazyListState
 import androidx.compose.material3.ExperimentalMaterial3Api
 import androidx.compose.material3.TopAppBarDefaults
 import androidx.compose.material3.rememberTopAppBarState
@@ -25,7 +26,6 @@ import androidx.compose.runtime.Composable
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.ui.Modifier
-import androidx.compose.ui.draw.shadow
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.input.nestedscroll.nestedScroll
 import androidx.compose.ui.platform.LocalLayoutDirection
@@ -40,9 +40,9 @@ import dev.chrisbanes.haze.materials.HazeMaterials
 import dev.chrisbanes.haze.rememberHazeState
 import io.element.android.compound.theme.ElementTheme
 import io.element.android.compound.tokens.generated.CompoundIcons
+import io.element.android.features.home.impl.components.HomeTopBar
 import io.element.android.features.home.impl.components.RoomListContentView
 import io.element.android.features.home.impl.components.RoomListMenuAction
-import io.element.android.features.home.impl.components.HomeTopBar
 import io.element.android.features.home.impl.model.RoomListRoomSummary
 import io.element.android.features.home.impl.roomlist.RoomListContextMenu
 import io.element.android.features.home.impl.roomlist.RoomListDeclineInviteMenu
@@ -63,6 +63,7 @@ import io.element.android.libraries.designsystem.theme.components.Scaffold
 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 kotlinx.coroutines.launch
 
 @Composable
 fun HomeView(
@@ -155,6 +156,8 @@ private fun HomeScaffold(
     }
 
     val hazeState = rememberHazeState()
+    val roomsLazyListState = rememberLazyListState()
+    val spacesLazyListState = rememberLazyListState()
 
     Scaffold(
         modifier = modifier.nestedScroll(scrollBehavior.nestedScrollConnection),
@@ -181,41 +184,39 @@ private fun HomeScaffold(
                         style = HazeMaterials.thick(),
                     )
                 } else {
-                    Modifier
-                        .background(ElementTheme.colors.bgCanvasDefault)
+                    Modifier.background(ElementTheme.colors.bgCanvasDefault)
                 }
             )
         },
         bottomBar = {
             if (state.showNavigationBar) {
-                NavigationBar(
-                    containerColor = Color.Transparent,
-                    modifier = Modifier
-                        .hazeEffect(
-                            state = hazeState,
-                            style = HazeMaterials.thick(),
-                        )
-                ) {
-                    HomeNavigationBarItem.entries.forEach { item ->
-                        val isSelected = state.currentHomeNavigationBarItem == item
-                        NavigationBarItem(
-                            selected = isSelected,
-                            onClick = {
-                                state.eventSink(HomeEvents.SelectHomeNavigationBarItem(item))
-                            },
-                            icon = {
-                                NavigationBarIcon(
-                                    imageVector = item.icon(isSelected),
-                                )
-                            },
-                            label = {
-                                NavigationBarText(
-                                    text = stringResource(item.labelRes),
-                                )
+                val coroutineScope = rememberCoroutineScope()
+                HomeBottomBar(
+                    currentHomeNavigationBarItem = state.currentHomeNavigationBarItem,
+                    onItemClick = { item ->
+                        // scroll to top if selecting the same item
+                        if (item == state.currentHomeNavigationBarItem) {
+                            val lazyListStateTarget = when (item) {
+                                HomeNavigationBarItem.Chats -> roomsLazyListState
+                                HomeNavigationBarItem.Spaces -> spacesLazyListState
                             }
-                        )
-                    }
-                }
+                            coroutineScope.launch {
+                                if (lazyListStateTarget.firstVisibleItemIndex > 10) {
+                                    lazyListStateTarget.scrollToItem(10)
+                                }
+                                // Also reset the scrollBehavior height offset as it's not triggered by programmatic scrolls
+                                scrollBehavior.state.heightOffset = 0f
+                                lazyListStateTarget.animateScrollToItem(0)
+                            }
+                        } else {
+                            state.eventSink(HomeEvents.SelectHomeNavigationBarItem(item))
+                        }
+                    },
+                    modifier = Modifier.hazeEffect(
+                        state = hazeState,
+                        style = HazeMaterials.thick(),
+                    )
+                )
             }
         },
         content = { padding ->
@@ -224,6 +225,7 @@ private fun HomeScaffold(
                     RoomListContentView(
                         contentState = roomListState.contentState,
                         filtersState = roomListState.filtersState,
+                        lazyListState = roomsLazyListState,
                         hideInvitesAvatars = roomListState.hideInvitesAvatars,
                         eventSink = roomListState.eventSink,
                         onSetUpRecoveryClick = onSetUpRecoveryClick,
@@ -261,6 +263,7 @@ private fun HomeScaffold(
                             .consumeWindowInsets(padding)
                             .hazeSource(state = hazeState),
                         state = state.homeSpacesState,
+                        lazyListState = spacesLazyListState,
                         onSpaceClick = { spaceId ->
                             onRoomClick(spaceId)
                         }
@@ -284,6 +287,38 @@ private fun HomeScaffold(
     )
 }
 
+@Composable
+private fun HomeBottomBar(
+    currentHomeNavigationBarItem: HomeNavigationBarItem,
+    onItemClick: (HomeNavigationBarItem) -> Unit,
+    modifier: Modifier = Modifier,
+) {
+    NavigationBar(
+        containerColor = Color.Transparent,
+        modifier = modifier
+    ) {
+        HomeNavigationBarItem.entries.forEach { item ->
+            val isSelected = currentHomeNavigationBarItem == item
+            NavigationBarItem(
+                selected = isSelected,
+                onClick = {
+                    onItemClick(item)
+                },
+                icon = {
+                    NavigationBarIcon(
+                        imageVector = item.icon(isSelected),
+                    )
+                },
+                label = {
+                    NavigationBarText(
+                        text = stringResource(item.labelRes),
+                    )
+                }
+            )
+        }
+    }
+}
+
 internal fun RoomListRoomSummary.contentType() = displayType.ordinal
 
 @PreviewsDayNight

features/home/impl/src/main/kotlin/io/element/android/features/home/impl/components/RoomListContentView.kt

@@ -18,6 +18,7 @@ import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.LazyListState
 import androidx.compose.foundation.lazy.itemsIndexed
 import androidx.compose.foundation.lazy.rememberLazyListState
 import androidx.compose.runtime.Composable
@@ -60,6 +61,7 @@ import kotlinx.collections.immutable.ImmutableList
 fun RoomListContentView(
     contentState: RoomListContentState,
     filtersState: RoomListFiltersState,
+    lazyListState: LazyListState,
     hideInvitesAvatars: Boolean,
     eventSink: (RoomListEvents) -> Unit,
     onSetUpRecoveryClick: () -> Unit,
@@ -97,6 +99,7 @@ fun RoomListContentView(
                 onSetUpRecoveryClick = onSetUpRecoveryClick,
                 onConfirmRecoveryKeyClick = onConfirmRecoveryKeyClick,
                 onRoomClick = onRoomClick,
+                lazyListState = lazyListState,
                 contentPadding = contentPadding,
             )
         }
@@ -176,6 +179,7 @@ private fun RoomsView(
     onConfirmRecoveryKeyClick: () -> Unit,
     onRoomClick: (RoomListRoomSummary) -> Unit,
     contentPadding: PaddingValues,
+    lazyListState: LazyListState,
     modifier: Modifier = Modifier,
 ) {
     if (state.summaries.isEmpty() && filtersState.hasAnyFilterSelected) {
@@ -192,6 +196,7 @@ private fun RoomsView(
             onConfirmRecoveryKeyClick = onConfirmRecoveryKeyClick,
             onRoomClick = onRoomClick,
             contentPadding = contentPadding,
+            lazyListState = lazyListState,
             modifier = modifier.fillMaxSize(),
         )
     }
@@ -206,9 +211,9 @@ private fun RoomsViewList(
     onConfirmRecoveryKeyClick: () -> Unit,
     onRoomClick: (RoomListRoomSummary) -> Unit,
     contentPadding: PaddingValues,
+    lazyListState: LazyListState,
     modifier: Modifier = Modifier,
 ) {
-    val lazyListState = rememberLazyListState()
     val visibleRange by remember {
         derivedStateOf {
             val layoutInfo = lazyListState.layoutInfo
@@ -343,6 +348,7 @@ internal fun RoomListContentViewPreview(@PreviewParameter(RoomListContentStatePr
         onConfirmRecoveryKeyClick = {},
         onRoomClick = {},
         onCreateRoomClick = {},
+        lazyListState = rememberLazyListState(),
         contentPadding = PaddingValues(0.dp),
     )
 }

features/home/impl/src/main/kotlin/io/element/android/features/home/impl/spaces/HomeSpacesView.kt

@@ -8,6 +8,8 @@
 package io.element.android.features.home.impl.spaces
 
 import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.LazyListState
+import androidx.compose.foundation.lazy.rememberLazyListState
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.tooling.preview.PreviewParameter
@@ -26,10 +28,14 @@ import kotlinx.collections.immutable.toImmutableList
 @Composable
 fun HomeSpacesView(
     state: HomeSpacesState,
+    lazyListState: LazyListState,
     onSpaceClick: (RoomId) -> Unit,
     modifier: Modifier = Modifier,
 ) {
-    LazyColumn(modifier) {
+    LazyColumn(
+        modifier = modifier,
+        state = lazyListState
+    ) {
         val space = state.space
         when (space) {
             CurrentSpace.Root -> {
@@ -77,6 +83,7 @@ internal fun HomeSpacesViewPreview(
 ) = ElementPreview {
     HomeSpacesView(
         state = state,
+        lazyListState = rememberLazyListState(),
         onSpaceClick = {},
         modifier = Modifier,
     )