implement show/hide header on scroll in LibraryScreen and prevent haptic feedback on re-selecting the current bottom bar item

app/src/main/java/eu/gaudian/translator/view/composable/BottomNavigationBar.kt

@@ -207,8 +207,10 @@ fun BottomNavigationBar(
                         NavigationBarItem(
                             selected = isSelected,
                             onClick = {
-                                haptic.performHapticFeedback(HapticFeedbackType.LongPress)
-                                if (screen == Screen.More) showMoreMenu = true else onItemSelected(screen)
+                                if (!isSelected) {
+                                    haptic.performHapticFeedback(HapticFeedbackType.LongPress)
+                                    if (screen == Screen.More) showMoreMenu = true else onItemSelected(screen)
+                                }
                             },
                             label = if (showLabels) {
                                 {

app/src/main/java/eu/gaudian/translator/view/library/LibraryComponents.kt

@@ -22,6 +22,7 @@ import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.LazyListState
 import androidx.compose.foundation.lazy.grid.GridCells
 import androidx.compose.foundation.lazy.grid.GridItemSpan
 import androidx.compose.foundation.lazy.grid.LazyVerticalGrid
@@ -315,6 +316,7 @@ fun AllCardsView(
     onItemClick: (VocabularyItem) -> Unit,
     onItemLongClick: (VocabularyItem) -> Unit,
     onDeleteClick: (VocabularyItem) -> Unit,
+    listState: LazyListState,
     modifier: Modifier = Modifier
 ) {
     if (vocabularyItems.isEmpty()) {
@@ -340,6 +342,7 @@ fun AllCardsView(
         }
     } else {
         LazyColumn(
+            state = listState,
             verticalArrangement = Arrangement.spacedBy(16.dp),
             modifier = modifier.fillMaxSize(),
             contentPadding = PaddingValues(bottom = 100.dp)

app/src/main/java/eu/gaudian/translator/view/library/LibraryScreen.kt

@@ -4,6 +4,10 @@ package eu.gaudian.translator.view.library
 
 import android.os.Parcelable
 import androidx.compose.animation.AnimatedVisibility
+import androidx.compose.animation.expandVertically
+import androidx.compose.animation.fadeIn
+import androidx.compose.animation.fadeOut
+import androidx.compose.animation.shrinkVertically
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
@@ -42,6 +46,7 @@ import androidx.compose.runtime.remember
 import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.runtime.saveable.rememberSaveable
 import androidx.compose.runtime.setValue
+import androidx.compose.runtime.snapshotFlow
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.platform.LocalContext
@@ -122,6 +127,10 @@ fun LibraryScreen(
 
     val vocabularyItems by vocabularyItemsFlow.collectAsStateWithLifecycle(initialValue = emptyList())
 
+    var isHeaderVisible by remember { mutableStateOf(true) }
+    var previousIndex by remember { mutableStateOf(0) }
+    var previousScrollOffset by remember { mutableStateOf(0) }
+
     // Set navigation context when vocabulary items are loaded
     LaunchedEffect(vocabularyItems) {
         if (vocabularyItems.isNotEmpty()) {
@@ -129,6 +138,24 @@ fun LibraryScreen(
         }
     }
 
+    LaunchedEffect(isCategoriesView, isInSelectionMode) {
+        if (isCategoriesView || isInSelectionMode) {
+            isHeaderVisible = true
+        }
+    }
+
+    LaunchedEffect(lazyListState, isCategoriesView, isInSelectionMode) {
+        if (isCategoriesView || isInSelectionMode) return@LaunchedEffect
+        snapshotFlow { lazyListState.firstVisibleItemIndex to lazyListState.firstVisibleItemScrollOffset }
+            .collect { (index, offset) ->
+                val isScrollingDown = index > previousIndex || (index == previousIndex && offset > previousScrollOffset)
+                val isAtTop = index == 0 && offset <= 4
+                isHeaderVisible = if (isAtTop) true else !isScrollingDown
+                previousIndex = index
+                previousScrollOffset = offset
+            }
+    }
+
     Box(
         modifier = modifier.fillMaxSize(),
         contentAlignment = Alignment.TopCenter
@@ -139,47 +166,55 @@ fun LibraryScreen(
                 .fillMaxSize()
                 .padding(horizontal = 24.dp),
         ) {
-            Spacer(modifier = Modifier.height(24.dp))
-            
-            if (isInSelectionMode) {
-                SelectionTopBar(
-                    selectionCount = selection.size,
-                    onCloseClick = { selection = emptySet() },
-                    onSelectAllClick = {
-                        selection = if (selection.size == vocabularyItems.size) emptySet() 
-                                   else vocabularyItems.map { it.id.toLong() }.toSet()
-                    },
-                    onDeleteClick = {
-                        vocabularyViewModel.deleteVocabularyItemsById(selection.map { it.toInt() })
-                        selection = emptySet()
-                    },
-                    onMoveToCategoryClick = { showCategoryDialog = true },
-                    onMoveToStageClick = { showStageDialog = true },
-                    isRemoveEnabled = false,
-                    onRemoveFromCategoryClick = {}
-                )
-            } else {
-                LibraryTopBar(
-                    onAddClick = { /* TODO: Add new card/category */ }
-                )
+            AnimatedVisibility(
+                visible = isHeaderVisible,
+                enter = fadeIn() + expandVertically(),
+                exit = fadeOut() + shrinkVertically()
+            ) {
+                Column {
+                    Spacer(modifier = Modifier.height(24.dp))
+
+                    if (isInSelectionMode) {
+                        SelectionTopBar(
+                            selectionCount = selection.size,
+                            onCloseClick = { selection = emptySet() },
+                            onSelectAllClick = {
+                                selection = if (selection.size == vocabularyItems.size) emptySet()
+                                           else vocabularyItems.map { it.id.toLong() }.toSet()
+                            },
+                            onDeleteClick = {
+                                vocabularyViewModel.deleteVocabularyItemsById(selection.map { it.toInt() })
+                                selection = emptySet()
+                            },
+                            onMoveToCategoryClick = { showCategoryDialog = true },
+                            onMoveToStageClick = { showStageDialog = true },
+                            isRemoveEnabled = false,
+                            onRemoveFromCategoryClick = {}
+                        )
+                    } else {
+                        LibraryTopBar(
+                            onAddClick = { /* TODO: Add new card/category */ }
+                        )
+                    }
+
+                    Spacer(modifier = Modifier.height(24.dp))
+
+                    SearchBar(
+                        searchQuery = filterState.searchQuery,
+                        onQueryChanged = { filterState = filterState.copy(searchQuery = it) },
+                        onFilterClick = { showFilterSheet = true }
+                    )
+
+                    Spacer(modifier = Modifier.height(24.dp))
+
+                    SegmentedControl(
+                        isCategoriesView = isCategoriesView,
+                        onTabSelected = { isCategoriesView = it }
+                    )
+
+                    Spacer(modifier = Modifier.height(24.dp))
+                }
             }
-            
-            Spacer(modifier = Modifier.height(24.dp))
-
-            SearchBar(
-                searchQuery = filterState.searchQuery,
-                onQueryChanged = { filterState = filterState.copy(searchQuery = it) },
-                onFilterClick = { showFilterSheet = true }
-            )
-
-            Spacer(modifier = Modifier.height(24.dp))
-
-            SegmentedControl(
-                isCategoriesView = isCategoriesView,
-                onTabSelected = { isCategoriesView = it }
-            )
-
-            Spacer(modifier = Modifier.height(24.dp))
 
             LibraryViewContainer(
                 isCategoriesView = isCategoriesView,
@@ -199,6 +234,7 @@ fun LibraryScreen(
                         vocabularyItems = vocabularyItems,
                         allLanguages = allLanguages,
                         selection = selection,
+                        listState = lazyListState,
                         onItemClick = { item ->
                             if (isInSelectionMode) {
                                 selection = if (selection.contains(item.id.toLong())) {

app/src/main/java/eu/gaudian/translator/view/vocabulary/NewVocListScreen.kt

@@ -268,6 +268,7 @@ fun NewVocListScreen(
                         vocabularyItems = vocabularyItems,
                         allLanguages = allLanguages,
                         selection = selection,
+                        listState = lazyListState,
                         onItemClick = { item ->
                             if (isInSelectionMode) {
                                 selection = if (selection.contains(item.id.toLong())) {
@@ -588,7 +589,8 @@ fun AllCardsView(
     selection: Set<Long>,
     onItemClick: (VocabularyItem) -> Unit,
     onItemLongClick: (VocabularyItem) -> Unit,
-    onDeleteClick: (VocabularyItem) -> Unit
+    onDeleteClick: (VocabularyItem) -> Unit,
+    listState: androidx.compose.foundation.lazy.LazyListState
 ) {
     if (vocabularyItems.isEmpty()) {
         Column(
@@ -613,6 +615,7 @@ fun AllCardsView(
         }
     } else {
         LazyColumn(
+            state = listState,
             verticalArrangement = Arrangement.spacedBy(16.dp),
             modifier = Modifier.fillMaxSize(),
             contentPadding = PaddingValues(bottom = 100.dp)