Implemented an approach to dynamically show/hide the XML-based bottomNavigationView from compose UI. We will remove this custom logic after we migrate the BottomNavigationView to compose.

* Refactored KiwixAppBar to support the scrolling behavior. By default, it will work as a normal toolbar, if on any screen there is a need to scroll the toolbar then pass the `TopAppBarDefaults.enterAlwaysScrollBehavior()` to `topAppBarScrollBehavior` and it will automatically do the job.

app/src/main/java/org/kiwix/kiwixmobile/main/KiwixMainActivity.kt

@@ -52,6 +52,7 @@ import org.kiwix.kiwixmobile.core.R.string
 import org.kiwix.kiwixmobile.core.base.FragmentActivityExtensions
 import org.kiwix.kiwixmobile.core.dao.NewBookDao
 import org.kiwix.kiwixmobile.core.downloader.downloadManager.DOWNLOAD_NOTIFICATION_TITLE
+import org.kiwix.kiwixmobile.core.downloader.downloadManager.ZERO
 import org.kiwix.kiwixmobile.core.extensions.applyEdgeToEdgeInsets
 import org.kiwix.kiwixmobile.core.extensions.toast
 import org.kiwix.kiwixmobile.core.main.ACTION_NEW_TAB
@@ -68,6 +69,7 @@ const val NAVIGATE_TO_ZIM_HOST_FRAGMENT = "navigate_to_zim_host_fragment"
 const val ACTION_GET_CONTENT = "GET_CONTENT"
 const val OPENING_ZIM_FILE_DELAY = 300L
 const val GET_CONTENT_SHORTCUT_ID = "get_content_shortcut"
+const val KIWIX_BOTTOM_BAR_ANIMATION_DURATION = 250L
 
 class KiwixMainActivity : CoreMainActivity() {
   private var actionMode: ActionMode? = null
@@ -223,6 +225,25 @@ class KiwixMainActivity : CoreMainActivity() {
     setDefaultDeviceLanguage()
   }
 
+  /**
+   * This is for manually showing/hiding the BottomNavigationView with animation from compose
+   * screens until we migrate the BottomNavigationView to compose. Once we migrate we will remove it.
+   *
+   * TODO Remove this once we migrate to compose.
+   */
+  fun toggleBottomNavigation(isVisible: Boolean) {
+    activityKiwixMainBinding.bottomNavView.animate()
+      ?.translationY(
+        if (isVisible) {
+          ZERO.toFloat()
+        } else {
+          activityKiwixMainBinding.bottomNavView.height.toFloat()
+        }
+      )
+      ?.setDuration(KIWIX_BOTTOM_BAR_ANIMATION_DURATION)
+      ?.start()
+  }
+
   private fun setDefaultDeviceLanguage() {
     if (sharedPreferenceUtil.prefDeviceDefaultLanguage.isEmpty()) {
       ConfigurationCompat.getLocales(

app/src/main/java/org/kiwix/kiwixmobile/nav/destination/library/local/LocalLibraryFragment.kt

@@ -36,9 +36,11 @@ import androidx.activity.result.ActivityResultLauncher
 import androidx.activity.result.contract.ActivityResultContracts
 import androidx.appcompat.app.AppCompatActivity
 import androidx.appcompat.view.ActionMode
+import androidx.compose.foundation.lazy.rememberLazyListState
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.Menu
 import androidx.compose.material3.SnackbarHostState
+import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.ui.platform.ComposeView
 import androidx.core.app.ActivityCompat
@@ -79,6 +81,7 @@ import org.kiwix.kiwixmobile.core.navigateToSettings
 import org.kiwix.kiwixmobile.core.reader.ZimFileReader
 import org.kiwix.kiwixmobile.core.reader.ZimReaderSource
 import org.kiwix.kiwixmobile.core.ui.components.NavigationIcon
+import org.kiwix.kiwixmobile.core.ui.components.rememberBottomNavigationVisibility
 import org.kiwix.kiwixmobile.core.ui.models.ActionMenuItem
 import org.kiwix.kiwixmobile.core.ui.models.IconItem
 import org.kiwix.kiwixmobile.core.utils.EXTERNAL_SELECT_POSITION
@@ -173,14 +176,19 @@ class LocalLibraryFragment : BaseFragment(), CopyMoveFileHandler.FileCopyMoveCal
   ): View? {
     LanguageUtils(requireActivity())
       .changeFont(requireActivity(), sharedPreferenceUtil)
-
-    val composeView = ComposeView(requireContext()).apply {
+    return ComposeView(requireContext()).apply {
       setContent {
+        val lazyListState = rememberLazyListState()
+        val isBottomNavVisible = rememberBottomNavigationVisibility(lazyListState)
+        LaunchedEffect(isBottomNavVisible) {
+          (requireActivity() as KiwixMainActivity).toggleBottomNavigation(isBottomNavVisible)
+        }
         updateLibraryScreenState(
           bottomNavigationHeight = getBottomNavigationHeight(),
           actionMenuItems = actionMenuItems()
         )
         LocalLibraryScreen(
+          listState = lazyListState,
           state = libraryScreenState.value,
           fabButtonClick = { filePickerButtonClick() },
           onClick = { onBookItemClick(it) },
@@ -192,25 +200,25 @@ class LocalLibraryFragment : BaseFragment(), CopyMoveFileHandler.FileCopyMoveCal
           NavigationIcon(
             iconItem = IconItem.Vector(Icons.Filled.Menu),
             contentDescription = string.open_drawer,
-            onClick = {
-              // Manually handle the navigation open/close.
-              // Since currently we are using the view based navigation drawer in other screens.
-              // Once we fully migrate to jetpack compose we will refactor this code to use the
-              // compose navigation.
-              // TODO Replace with compose based navigation when migration is done.
-              val activity = activity as CoreMainActivity
-              if (activity.navigationDrawerIsOpen()) {
-                activity.closeNavigationDrawer()
-              } else {
-                activity.openNavigationDrawer()
-              }
-            }
+            onClick = { navigationIconClick() }
           )
         }
       }
     }
+  }
 
-    return composeView
+  private fun navigationIconClick() {
+    // Manually handle the navigation open/close.
+    // Since currently we are using the view based navigation drawer in other screens.
+    // Once we fully migrate to jetpack compose we will refactor this code to use the
+    // compose navigation.
+    // TODO Replace with compose based navigation when migration is done.
+    val activity = activity as CoreMainActivity
+    if (activity.navigationDrawerIsOpen()) {
+      activity.closeNavigationDrawer()
+    } else {
+      activity.openNavigationDrawer()
+    }
   }
 
   private fun actionMenuItems() = listOf(

app/src/main/java/org/kiwix/kiwixmobile/nav/destination/library/local/LocalLibraryScreen.kt

@@ -34,12 +34,14 @@ import androidx.compose.material3.Icon
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Scaffold
 import androidx.compose.material3.Text
+import androidx.compose.material3.TopAppBarDefaults
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.MutableState
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.input.nestedscroll.nestedScroll
 import androidx.compose.ui.platform.LocalDensity
 import androidx.compose.ui.res.painterResource
 import androidx.compose.ui.res.stringResource
@@ -61,8 +63,7 @@ import org.kiwix.kiwixmobile.core.ui.theme.Black
 import org.kiwix.kiwixmobile.core.ui.theme.KiwixTheme
 import org.kiwix.kiwixmobile.core.ui.theme.White
 import org.kiwix.kiwixmobile.core.utils.ComposeDimens.EIGHT_DP
-import org.kiwix.kiwixmobile.core.utils.ComposeDimens.SIXTEEN_DP
-import org.kiwix.kiwixmobile.core.utils.ComposeDimens.TEN_DP
+import org.kiwix.kiwixmobile.core.utils.ComposeDimens.FAB_ICON_BOTTOM_MARGIN
 import org.kiwix.kiwixmobile.core.zim_manager.fileselect_view.adapter.BooksOnDiskListItem
 import org.kiwix.kiwixmobile.core.zim_manager.fileselect_view.adapter.BooksOnDiskListItem.BookOnDisk
 import org.kiwix.kiwixmobile.ui.BookItem
@@ -74,6 +75,7 @@ import org.kiwix.kiwixmobile.zimManager.fileselectView.FileSelectListState
 @Composable
 fun LocalLibraryScreen(
   state: LocalLibraryScreenState,
+  listState: LazyListState,
   onRefresh: () -> Unit,
   onDownloadButtonClick: () -> Unit,
   fabButtonClick: () -> Unit,
@@ -82,14 +84,18 @@ fun LocalLibraryScreen(
   onMultiSelect: ((BookOnDisk) -> Unit)? = null,
   navigationIcon: @Composable () -> Unit
 ) {
-  val (bottomNavHeight, lazyListState) = rememberScrollBehavior(state)
+  val (bottomNavHeight, lazyListState) = rememberScrollBehavior(state, listState)
+  val scrollBehavior = TopAppBarDefaults.enterAlwaysScrollBehavior()
   KiwixTheme {
     Scaffold(
       snackbarHost = { KiwixSnackbarHost(snackbarHostState = state.snackBarHostState) },
       topBar = {
-        KiwixAppBar(R.string.library, navigationIcon, state.actionMenuItems, lazyListState)
+        KiwixAppBar(R.string.library, navigationIcon, state.actionMenuItems, scrollBehavior)
       },
-      modifier = Modifier.systemBarsPadding()
+      floatingActionButton = { SelectFileButton(fabButtonClick) },
+      modifier = Modifier
+        .systemBarsPadding()
+        .nestedScroll(scrollBehavior.nestedScrollConnection)
     ) { contentPadding ->
       SwipeRefreshLayout(
         isRefreshing = state.swipeRefreshItem.first,
@@ -117,13 +123,6 @@ fun LocalLibraryScreen(
             lazyListState
           )
         }
-
-        SelectFileButton(
-          fabButtonClick,
-          Modifier
-            .align(Alignment.BottomEnd)
-            .padding(end = SIXTEEN_DP, bottom = TEN_DP)
-        )
       }
     }
   }
@@ -131,11 +130,13 @@ fun LocalLibraryScreen(
 
 @Composable
 private fun rememberScrollBehavior(
-  state: LocalLibraryScreenState
+  state: LocalLibraryScreenState,
+  listState: LazyListState,
 ): Pair<MutableState<Dp>, LazyListState> {
   val bottomNavHeightInDp = with(LocalDensity.current) { state.bottomNavigationHeight.toDp() }
   val bottomNavHeight = remember { mutableStateOf(bottomNavHeightInDp) }
   val lazyListState = rememberLazyListScrollListener(
+    lazyListState = listState,
     onScrollChanged = { direction ->
       when (direction) {
         ScrollDirection.SCROLL_UP -> {
@@ -185,10 +186,10 @@ private fun BookItemList(
 }
 
 @Composable
-private fun SelectFileButton(fabButtonClick: () -> Unit, modifier: Modifier) {
+private fun SelectFileButton(fabButtonClick: () -> Unit) {
   FloatingActionButton(
     onClick = fabButtonClick,
-    modifier = modifier,
+    modifier = Modifier.padding(bottom = FAB_ICON_BOTTOM_MARGIN),
     containerColor = Black,
     shape = MaterialTheme.shapes.extraLarge
   ) {

app/src/main/java/org/kiwix/kiwixmobile/webserver/ZimHostScreen.kt

@@ -35,6 +35,7 @@ import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.widthIn
 import androidx.compose.foundation.lazy.LazyColumn
 import androidx.compose.foundation.lazy.itemsIndexed
+import androidx.compose.material3.ExperimentalMaterial3Api
 import androidx.compose.material3.Scaffold
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.remember
@@ -69,6 +70,7 @@ import org.kiwix.kiwixmobile.ui.ZimFilesLanguageHeader
 const val START_SERVER_BUTTON_TESTING_TAG = "startServerButtonTestingTag"
 const val QR_IMAGE_TESTING_TAG = "qrImageTestingTag"
 
+@OptIn(ExperimentalMaterial3Api::class)
 @Suppress("ComposableLambdaParameterNaming", "LongParameterList")
 @Composable
 fun ZimHostScreen(

core/src/main/java/org/kiwix/kiwixmobile/core/main/AddNoteDialogScreen.kt

@@ -25,6 +25,7 @@ import androidx.compose.foundation.layout.heightIn
 import androidx.compose.foundation.layout.imePadding
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.text.KeyboardOptions
+import androidx.compose.material3.ExperimentalMaterial3Api
 import androidx.compose.material3.HorizontalDivider
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Scaffold
@@ -57,6 +58,7 @@ const val SAVE_MENU_BUTTON_TESTING_TAG = "saveMenuButtonTestingTag"
 const val SHARE_MENU_BUTTON_TESTING_TAG = "shareMenuButtonTestingTag"
 const val DELETE_MENU_BUTTON_TESTING_TAG = "deleteMenuButtonTestingTag"
 
+@OptIn(ExperimentalMaterial3Api::class)
 @Suppress("ComposableLambdaParameterNaming")
 @Composable
 fun AddNoteDialogScreen(

core/src/main/java/org/kiwix/kiwixmobile/core/ui/components/KiwixAppBar.kt

@@ -19,20 +19,20 @@
 package org.kiwix.kiwixmobile.core.ui.components
 
 import androidx.annotation.StringRes
-import androidx.compose.animation.core.animateDpAsState
-import androidx.compose.animation.core.tween
-import androidx.compose.foundation.background
 import androidx.compose.foundation.isSystemInDarkTheme
+import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Row
-import androidx.compose.foundation.layout.Spacer
-import androidx.compose.foundation.layout.fillMaxWidth
-import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.lazy.LazyListState
+import androidx.compose.material3.ExperimentalMaterial3Api
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Text
+import androidx.compose.material3.TopAppBar
+import androidx.compose.material3.TopAppBarDefaults
+import androidx.compose.material3.TopAppBarScrollBehavior
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
@@ -47,55 +47,58 @@ import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.platform.testTag
 import androidx.compose.ui.res.stringResource
-import androidx.compose.ui.unit.dp
+import androidx.compose.ui.text.style.TextOverflow
+import org.kiwix.kiwixmobile.core.downloader.downloadManager.ZERO
 import org.kiwix.kiwixmobile.core.ui.models.ActionMenuItem
 import org.kiwix.kiwixmobile.core.ui.models.toPainter
 import org.kiwix.kiwixmobile.core.ui.theme.Black
 import org.kiwix.kiwixmobile.core.ui.theme.KiwixTheme
 import org.kiwix.kiwixmobile.core.ui.theme.MineShaftGray350
 import org.kiwix.kiwixmobile.core.ui.theme.White
-import org.kiwix.kiwixmobile.core.utils.ComposeDimens.KIWIX_APP_BAR_HEIGHT
 import org.kiwix.kiwixmobile.core.utils.ComposeDimens.SIXTEEN_DP
-import org.kiwix.kiwixmobile.core.utils.ComposeDimens.TWO_DP
 
 const val TOOLBAR_TITLE_TESTING_TAG = "toolbarTitle"
 
+@OptIn(ExperimentalMaterial3Api::class)
 @Composable
 fun KiwixAppBar(
   @StringRes titleId: Int,
   navigationIcon: @Composable () -> Unit,
   actionMenuItems: List<ActionMenuItem> = emptyList(),
-  // If this state is provided, the app bar will automatically hide on scroll down and show
-  // on scroll up, same like scrollingToolbar.
-  lazyListState: LazyListState? = null,
+  topAppBarScrollBehavior: TopAppBarScrollBehavior = TopAppBarDefaults.pinnedScrollBehavior(),
   // Optional search bar, used in fragments that require it
   searchBar: (@Composable () -> Unit)? = null
 ) {
-  val isToolbarVisible = rememberToolbarVisibility(lazyListState)
-
-  val appBarHeight by animateDpAsState(
-    targetValue = if (isToolbarVisible) KIWIX_APP_BAR_HEIGHT else 0.dp,
-    animationSpec = tween(durationMillis = 250)
-  )
   KiwixTheme {
-    Row(
-      modifier = Modifier
-        .fillMaxWidth()
-        .height(appBarHeight)
-        .background(color = Black),
-      verticalAlignment = Alignment.CenterVertically
-    ) {
-      Spacer(Modifier.padding(start = TWO_DP))
-      navigationIcon()
-      searchBar?.let {
-        // Display the search bar when provided
-        it()
-      } ?: run {
-        // Otherwise, show the title
-        AppBarTitle(titleId)
-      }
-      Spacer(Modifier.weight(1f))
-      ActionMenu(actionMenuItems)
+    TopAppBar(
+      title = { AppBarTitleSection(titleId, searchBar) },
+      navigationIcon = navigationIcon,
+      actions = { ActionMenu(actionMenuItems) },
+      scrollBehavior = topAppBarScrollBehavior,
+      colors = TopAppBarDefaults.topAppBarColors(
+        containerColor = Black,
+        scrolledContainerColor = Black
+      )
+    )
+  }
+}
+
+@Suppress("ComposableLambdaParameterNaming")
+@Composable
+private fun AppBarTitleSection(
+  @StringRes titleId: Int,
+  searchBar: (@Composable () -> Unit)? = null
+) {
+  Box(
+    modifier = Modifier
+      .fillMaxSize()
+      .padding(start = SIXTEEN_DP),
+    contentAlignment = Alignment.CenterStart
+  ) {
+    searchBar?.let {
+      it()
+    } ?: run {
+      AppBarTitle(titleId)
     }
   }
 }
@@ -113,9 +116,10 @@ private fun AppBarTitle(
     text = stringResource(titleId),
     color = appBarTitleColor,
     style = MaterialTheme.typography.titleMedium,
+    overflow = TextOverflow.Ellipsis,
+    maxLines = 1,
     modifier = Modifier
-      .padding(horizontal = SIXTEEN_DP)
-      .testTag(TOOLBAR_TITLE_TESTING_TAG)
+      .testTag(TOOLBAR_TITLE_TESTING_TAG),
   )
 }
 
@@ -139,9 +143,9 @@ private fun ActionMenu(actionMenuItems: List<ActionMenuItem>) {
 }
 
 @Composable
-private fun rememberToolbarVisibility(lazyListState: LazyListState?): Boolean {
+fun rememberBottomNavigationVisibility(lazyListState: LazyListState?): Boolean {
   var isToolbarVisible by remember { mutableStateOf(true) }
-  var lastScrollIndex by remember { mutableIntStateOf(0) }
+  var lastScrollIndex by remember { mutableIntStateOf(ZERO) }
   val updatedLazyListState = rememberUpdatedState(lazyListState)
 
   LaunchedEffect(updatedLazyListState) {

core/src/main/java/org/kiwix/kiwixmobile/core/ui/components/LazyListScrollListener.kt

@@ -19,7 +19,6 @@
 package org.kiwix.kiwixmobile.core.ui.components
 
 import androidx.compose.foundation.lazy.LazyListState
-import androidx.compose.foundation.lazy.rememberLazyListState
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
@@ -34,10 +33,10 @@ const val ONE_THOUSAND = 1000
 
 @Composable
 fun rememberLazyListScrollListener(
+  lazyListState: LazyListState,
   onScrollChanged: (ScrollDirection) -> Unit,
   scrollThreshold: Int = 20
 ): LazyListState {
-  val lazyListState = rememberLazyListState()
   val updatedOnScrollChanged = rememberUpdatedState(onScrollChanged)
 
   var previousScrollPosition by remember { mutableIntStateOf(0) }

core/src/main/java/org/kiwix/kiwixmobile/core/utils/ComposeDimens.kt

@@ -97,5 +97,5 @@ object ComposeDimens {
   val BOOK_ICON_SIZE = 40.dp
 
   // LocalLibraryFragment dimens
-  val FAB_ICON_BOTTOM_MARGIN = 66.dp
+  val FAB_ICON_BOTTOM_MARGIN = 50.dp
 }