Fixed: Pressing the back button no longer reopens the Search fragment when you’re on the Reader fragment and navigated there from Search (which was happening before).

* Fixed: Pressing the back button now correctly closes the left drawer when it’s open on the Local Library or Online fragments.
* Introduced: A common mechanism to support back press handling across all fragments and the activity, and added support for "Periodic back navigation".

app/src/androidTest/java/org/kiwix/kiwixmobile/download/DownloadTest.kt

@@ -51,11 +51,9 @@ import org.kiwix.kiwixmobile.core.main.CoreMainActivity
 import org.kiwix.kiwixmobile.core.utils.LanguageUtils.Companion.handleLocaleChange
 import org.kiwix.kiwixmobile.core.utils.SharedPreferenceUtil
 import org.kiwix.kiwixmobile.core.utils.TestingUtils.COMPOSE_TEST_RULE_ORDER
-import org.kiwix.kiwixmobile.core.utils.TestingUtils.RETRY_RULE_ORDER
 import org.kiwix.kiwixmobile.main.KiwixMainActivity
 import org.kiwix.kiwixmobile.main.topLevel
 import org.kiwix.kiwixmobile.nav.destination.library.library
-import org.kiwix.kiwixmobile.testutils.RetryRule
 import org.kiwix.kiwixmobile.testutils.TestUtils
 import org.kiwix.kiwixmobile.testutils.TestUtils.closeSystemDialogs
 import org.kiwix.kiwixmobile.testutils.TestUtils.isSystemUINotRespondingDialogVisible
@@ -65,9 +63,9 @@ import java.util.concurrent.TimeUnit
 
 @LargeTest
 class DownloadTest : BaseActivityTest() {
-  @Rule(order = RETRY_RULE_ORDER)
+  // @Rule(order = RETRY_RULE_ORDER)
-  @JvmField
+  // @JvmField
-  val retryRule = RetryRule()
+  // val retryRule = RetryRule()
 
   @get:Rule(order = COMPOSE_TEST_RULE_ORDER)
   val composeTestRule = createComposeRule()

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

@@ -18,6 +18,8 @@
 
 package org.kiwix.kiwixmobile.main
 
+import androidx.activity.compose.BackHandler
+import androidx.activity.compose.LocalActivity
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.fillMaxSize
@@ -75,6 +77,7 @@ fun KiwixMainActivityScreen(
   val navBackStackEntry by navController.currentBackStackEntryAsState()
   val currentRoute = navBackStackEntry?.destination?.route
   val shouldShowBottomBar = currentRoute in topLevelDestinationsRoute && shouldShowBottomAppBar
+  OnUserBackPressed(leftDrawerState, uiCoroutineScope, currentRoute, navController)
   KiwixTheme {
     ModalNavigationDrawer(
       drawerState = leftDrawerState,
@@ -119,6 +122,33 @@ fun KiwixMainActivityScreen(
   }
 }
 
+@Composable
+private fun OnUserBackPressed(
+  leftDrawerState: DrawerState,
+  uiCoroutineScope: CoroutineScope,
+  currentRoute: String?,
+  navController: NavHostController
+) {
+  val activity = LocalActivity.current
+  BackHandler(enabled = true) {
+    when {
+      leftDrawerState.isOpen -> uiCoroutineScope.launch { leftDrawerState.close() }
+
+      currentRoute == KiwixDestination.Reader.route &&
+        navController.previousBackStackEntry?.destination?.route != KiwixDestination.Search.route -> {
+        activity?.finish()
+      }
+
+      else -> {
+        val popped = navController.popBackStack()
+        if (!popped) {
+          activity?.finish()
+        }
+      }
+    }
+  }
+}
+
 @OptIn(ExperimentalMaterial3Api::class)
 @Composable
 fun BottomNavigationBar(

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

@@ -66,6 +66,7 @@ import org.kiwix.kiwixmobile.cachedComponent
 import org.kiwix.kiwixmobile.core.R.string
 import org.kiwix.kiwixmobile.core.base.BaseActivity
 import org.kiwix.kiwixmobile.core.base.BaseFragment
+import org.kiwix.kiwixmobile.core.base.FragmentActivityExtensions
 import org.kiwix.kiwixmobile.core.downloader.downloadManager.ZERO
 import org.kiwix.kiwixmobile.core.extensions.ActivityExtensions.isManageExternalStoragePermissionGranted
 import org.kiwix.kiwixmobile.core.extensions.ActivityExtensions.navigate
@@ -200,7 +201,9 @@ class LocalLibraryFragment : BaseFragment(), CopyMoveFileHandler.FileCopyMoveCal
           onMultiSelect = { offerAction(RequestSelect(it)) },
           onRefresh = { onSwipeRefresh() },
           onDownloadButtonClick = { downloadBookButtonClick() },
-          bottomAppBarScrollBehaviour = (requireActivity() as CoreMainActivity).bottomAppBarScrollBehaviour
+          bottomAppBarScrollBehaviour = (requireActivity() as CoreMainActivity).bottomAppBarScrollBehaviour,
+          navHostController = (requireActivity() as CoreMainActivity).navController,
+          onUserBackPressed = { onUserBackPressed() }
         ) {
           NavigationIcon(
             iconItem = IconItem.Vector(Icons.Filled.Menu),
@@ -213,12 +216,16 @@ class LocalLibraryFragment : BaseFragment(), CopyMoveFileHandler.FileCopyMoveCal
     }
   }
 
+  private fun onUserBackPressed(): FragmentActivityExtensions.Super {
+    val coreMainActivity = (activity as? CoreMainActivity)
+    if (coreMainActivity?.navigationDrawerIsOpen() == true) {
+      coreMainActivity.closeNavigationDrawer()
+      return FragmentActivityExtensions.Super.ShouldNotCall
+    }
+    return FragmentActivityExtensions.Super.ShouldCall
+  }
+
   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()

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

@@ -47,9 +47,12 @@ import androidx.compose.ui.res.painterResource
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.style.TextAlign
+import androidx.navigation.NavHostController
 import org.kiwix.kiwixmobile.R.string
 import org.kiwix.kiwixmobile.core.R
+import org.kiwix.kiwixmobile.core.base.FragmentActivityExtensions
 import org.kiwix.kiwixmobile.core.main.reader.CONTENT_LOADING_PROGRESSBAR_TESTING_TAG
+import org.kiwix.kiwixmobile.core.main.reader.OnBackPressed
 import org.kiwix.kiwixmobile.core.ui.components.ContentLoadingProgressBar
 import org.kiwix.kiwixmobile.core.ui.components.KiwixAppBar
 import org.kiwix.kiwixmobile.core.ui.components.KiwixButton
@@ -73,7 +76,7 @@ const val BOOK_LIST_TESTING_TAG = "bookListTestingTag"
 const val SELECT_FILE_BUTTON_TESTING_TAG = "selectFileButtonTestingTag"
 
 @OptIn(ExperimentalMaterial3Api::class)
-@Suppress("ComposableLambdaParameterNaming")
+@Suppress("ComposableLambdaParameterNaming", "LongParameterList")
 @Composable
 fun LocalLibraryScreen(
   state: LocalLibraryScreenState,
@@ -85,6 +88,8 @@ fun LocalLibraryScreen(
   onLongClick: ((BookOnDisk) -> Unit)? = null,
   onMultiSelect: ((BookOnDisk) -> Unit)? = null,
   bottomAppBarScrollBehaviour: BottomAppBarScrollBehavior?,
+  onUserBackPressed: () -> FragmentActivityExtensions.Super,
+  navHostController: NavHostController,
   navigationIcon: @Composable () -> Unit
 ) {
   val scrollBehavior = TopAppBarDefaults.enterAlwaysScrollBehavior()
@@ -117,6 +122,7 @@ fun LocalLibraryScreen(
           .fillMaxSize()
           .padding(contentPadding)
       ) {
+        OnBackPressed(onUserBackPressed, navHostController)
         if (state.scanningProgressItem.first) {
           ContentLoadingProgressBar(
             modifier = Modifier.testTag(CONTENT_LOADING_PROGRESSBAR_TESTING_TAG),

app/src/main/java/org/kiwix/kiwixmobile/nav/destination/library/online/OnlineLibraryFragment.kt

@@ -29,7 +29,6 @@ import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
 import android.widget.Toast
-import androidx.appcompat.app.AppCompatActivity
 import androidx.compose.foundation.lazy.rememberLazyListState
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.automirrored.filled.ArrowBack
@@ -271,7 +270,9 @@ class OnlineLibraryFragment : BaseFragment(), FragmentActivityExtensions {
             onClick = { navigationIconClick(onlineLibraryScreenState.value.value.isSearchActive) }
           )
         },
-        bottomAppBarScrollBehaviour = (requireActivity() as CoreMainActivity).bottomAppBarScrollBehaviour
+        bottomAppBarScrollBehaviour = (requireActivity() as CoreMainActivity).bottomAppBarScrollBehaviour,
+        navHostController = (requireActivity() as CoreMainActivity).navController,
+        onUserBackPressed = { onUserBackPressed() }
       )
       DialogHost(alertDialogShower)
     }
@@ -460,8 +461,13 @@ class OnlineLibraryFragment : BaseFragment(), FragmentActivityExtensions {
     composeView = null
   }
 
-  override fun onBackPressed(activity: AppCompatActivity): FragmentActivityExtensions.Super {
+  @Suppress("ReturnCount")
-    if (isKeyboardVisible() || onlineLibraryScreenState.value.value.isSearchActive) {
+  private fun onUserBackPressed(): FragmentActivityExtensions.Super {
+    val coreMainActivity = (activity as? CoreMainActivity)
+    if (coreMainActivity?.navigationDrawerIsOpen() == true) {
+      coreMainActivity.closeNavigationDrawer()
+      return FragmentActivityExtensions.Super.ShouldNotCall
+    } else if (isKeyboardVisible() || onlineLibraryScreenState.value.value.isSearchActive) {
       closeKeyboard()
       closeSearch()
       return FragmentActivityExtensions.Super.ShouldNotCall

app/src/main/java/org/kiwix/kiwixmobile/nav/destination/library/online/OnlineLibraryScreen.kt

@@ -56,12 +56,15 @@ import androidx.compose.ui.semantics.semantics
 import androidx.compose.ui.semantics.testTag
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.style.TextAlign
+import androidx.navigation.NavHostController
 import kotlinx.coroutines.flow.distinctUntilChanged
 import kotlinx.coroutines.flow.filter
 import org.kiwix.kiwixmobile.core.R.string
+import org.kiwix.kiwixmobile.core.base.FragmentActivityExtensions
 import org.kiwix.kiwixmobile.core.downloader.downloadManager.FIVE
 import org.kiwix.kiwixmobile.core.downloader.downloadManager.ZERO
 import org.kiwix.kiwixmobile.core.extensions.hideKeyboardOnLazyColumnScroll
+import org.kiwix.kiwixmobile.core.main.reader.OnBackPressed
 import org.kiwix.kiwixmobile.core.ui.components.ContentLoadingProgressBar
 import org.kiwix.kiwixmobile.core.ui.components.KiwixAppBar
 import org.kiwix.kiwixmobile.core.ui.components.KiwixSearchView
@@ -99,6 +102,8 @@ fun OnlineLibraryScreen(
   actionMenuItems: List<ActionMenuItem>,
   listState: LazyListState,
   bottomAppBarScrollBehaviour: BottomAppBarScrollBehavior?,
+  onUserBackPressed: () -> FragmentActivityExtensions.Super,
+  navHostController: NavHostController,
   navigationIcon: @Composable () -> Unit,
 ) {
   val scrollBehavior = TopAppBarDefaults.enterAlwaysScrollBehavior()
@@ -135,6 +140,7 @@ fun OnlineLibraryScreen(
             end = paddingValues.calculateEndPadding(LocalLayoutDirection.current),
           )
       ) {
+        OnBackPressed(onUserBackPressed, navHostController)
         OnlineLibraryScreenContent(state, listState)
       }
     }

core/src/main/AndroidManifest.xml

@@ -52,7 +52,7 @@
   <application
     android:allowBackup="true"
     android:dataExtractionRules="@xml/data_extraction_rules"
-    android:enableOnBackInvokedCallback="false"
+    android:enableOnBackInvokedCallback="true"
     android:fullBackupContent="@xml/backup_rules"
     android:hardwareAccelerated="true"
     android:hasFragileUserData="true"

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

@@ -24,7 +24,6 @@ import android.os.Process
 import android.view.ActionMode
 import android.view.Menu
 import android.view.MenuItem
-import androidx.activity.OnBackPressedCallback
 import androidx.appcompat.app.ActionBarDrawerToggle
 import androidx.appcompat.app.AppCompatActivity
 import androidx.compose.material3.BottomAppBarScrollBehavior
@@ -38,7 +37,6 @@ import androidx.lifecycle.lifecycleScope
 import androidx.navigation.NavDirections
 import androidx.navigation.NavHostController
 import androidx.navigation.NavOptions
-import com.google.android.material.navigation.NavigationView
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.launch
@@ -47,7 +45,6 @@ import org.kiwix.kiwixmobile.core.CoreApp
 import org.kiwix.kiwixmobile.core.R
 import org.kiwix.kiwixmobile.core.base.BaseActivity
 import org.kiwix.kiwixmobile.core.base.FragmentActivityExtensions
-import org.kiwix.kiwixmobile.core.base.FragmentActivityExtensions.Super.ShouldCall
 import org.kiwix.kiwixmobile.core.data.remote.ObjectBoxToLibkiwixMigrator
 import org.kiwix.kiwixmobile.core.data.remote.ObjectBoxToRoomMigrator
 import org.kiwix.kiwixmobile.core.di.components.CoreActivityComponent
@@ -144,6 +141,11 @@ abstract class CoreMainActivity : BaseActivity(), WebViewProvider {
    */
   val enableLeftDrawer = mutableStateOf(true)
 
+  /**
+   * For managing the back press of fragments.
+   */
+  val customBackHandler = mutableStateOf<(() -> FragmentActivityExtensions.Super)?>(null)
+
   /**
    * For managing the the showing/hiding the bottomAppBar when scrolling.
    */
@@ -197,7 +199,6 @@ abstract class CoreMainActivity : BaseActivity(), WebViewProvider {
     lifecycleScope.launch(Dispatchers.IO) {
       createApplicationShortcuts()
     }
-    handleBackPressed()
     leftDrawerMenu.addAll(leftNavigationDrawerMenuItems)
   }
 
@@ -231,11 +232,6 @@ abstract class CoreMainActivity : BaseActivity(), WebViewProvider {
     }
   }
 
-  override fun onDestroy() {
-    onBackPressedCallBack.remove()
-    super.onDestroy()
-  }
-
   override fun onStop() {
     startMonitoringDownloads()
     downloadMonitor.stopListeningDownloads()
@@ -253,11 +249,6 @@ abstract class CoreMainActivity : BaseActivity(), WebViewProvider {
     }
   }
 
-  @Suppress("UnusedParameter")
-  private fun NavigationView.setLockMode(lockMode: Int) {
-    // drawerContainerLayout.setDrawerLockMode(lockMode, this)
-  }
-
   @Suppress("DEPRECATION")
   override fun onRequestPermissionsResult(
     requestCode: Int,
@@ -339,41 +330,6 @@ abstract class CoreMainActivity : BaseActivity(), WebViewProvider {
     externalLinkOpener.openExternalUrl(KIWIX_SUPPORT_URL.toUri().browserIntent(), false)
   }
 
-  private fun handleBackPressed() {
-    onBackPressedDispatcher.addCallback(this, onBackPressedCallBack)
-  }
-
-  private val onBackPressedCallBack =
-    object : OnBackPressedCallback(true) {
-      override fun handleOnBackPressed() {
-        if (navigationDrawerIsOpen()) {
-          closeNavigationDrawer()
-          return
-        }
-        if (activeFragments().filterIsInstance<FragmentActivityExtensions>().isEmpty()) {
-          isEnabled = false
-          return onBackPressedDispatcher.onBackPressed().also {
-            isEnabled = true
-          }
-        }
-        activeFragments().filterIsInstance<FragmentActivityExtensions>().forEach {
-          if (it.onBackPressed(this@CoreMainActivity) == ShouldCall) {
-            if (navController.currentDestination?.route?.equals(readerFragmentRoute) == true &&
-              navController.previousBackStackEntry?.destination
-                ?.route?.equals(searchFragmentRoute) == false
-            ) {
-              drawerToggle = null
-              finish()
-            } else {
-              isEnabled = false
-              onBackPressedDispatcher.onBackPressed()
-              isEnabled = true
-            }
-          }
-        }
-      }
-    }
-
   override fun onCreateOptionsMenu(menu: Menu): Boolean {
     if (activeFragments().filterIsInstance<FragmentActivityExtensions>().isEmpty()) {
       return super.onCreateOptionsMenu(menu)

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

@@ -1,125 +0,0 @@
-/*
- * Kiwix Android
- * Copyright (c) 2020 Kiwix <android.kiwix.org>
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program. If not, see <http://www.gnu.org/licenses/>.
- *
- */
-
-package org.kiwix.kiwixmobile.core.main
-
-import android.graphics.Typeface
-import android.view.LayoutInflater
-import android.view.View
-import android.view.ViewGroup
-import androidx.recyclerview.widget.RecyclerView.Adapter
-import androidx.recyclerview.widget.RecyclerView.ViewHolder
-import org.kiwix.kiwixmobile.core.R
-import org.kiwix.kiwixmobile.core.base.adapter.BaseViewHolder
-import org.kiwix.kiwixmobile.core.databinding.SectionListBinding
-
-class TableDrawerAdapter constructor(
-  private val listener: TableClickListener
-) : Adapter<ViewHolder>() {
-  private var title: String = ""
-  private val sections: MutableList<DocumentSection> = mutableListOf()
-
-  fun setSections(sections: List<DocumentSection>) {
-    this.sections.clear()
-    this.sections.addAll(sections)
-  }
-
-  fun setTitle(title: String) {
-    this.title = title
-  }
-
-  override fun getItemViewType(position: Int): Int {
-    return if (position == 0) {
-      0
-    } else {
-      1
-    }
-  }
-
-  override fun onCreateViewHolder(
-    parent: ViewGroup,
-    viewType: Int
-  ): ViewHolder {
-    val binding = SectionListBinding.inflate(LayoutInflater.from(parent.context), parent, false)
-    return if (viewType == 0) {
-      HeaderTableDrawerViewHolder(binding)
-    } else {
-      SectionTableDrawerViewHolder(binding)
-    }
-  }
-
-  override fun getItemCount(): Int = sections.size + 1
-
-  override fun onBindViewHolder(holder: ViewHolder, position: Int) {
-    when (holder) {
-      is HeaderTableDrawerViewHolder -> {
-        holder.bind(title)
-        holder.itemView.setOnClickListener(listener::onHeaderClick)
-      }
-
-      is SectionTableDrawerViewHolder -> {
-        val titleAdjustedPosition = position - 1
-        holder.bind(sections[titleAdjustedPosition])
-        holder.itemView.setOnClickListener {
-          listener.onSectionClick(it, titleAdjustedPosition)
-        }
-      }
-
-      else -> {
-        throw IllegalStateException("Unknown ViewHolder $holder found")
-      }
-    }
-  }
-
-  interface TableClickListener {
-    fun onHeaderClick(view: View?)
-    fun onSectionClick(view: View?, position: Int)
-  }
-
-  class HeaderTableDrawerViewHolder(private val sectionListBinding: SectionListBinding) :
-    BaseViewHolder<String>(sectionListBinding.root) {
-    override fun bind(item: String) {
-      val context = itemView.context
-      sectionListBinding.titleText.typeface = Typeface.DEFAULT_BOLD
-      sectionListBinding.titleText.text =
-        when {
-          item.isNotEmpty() -> item
-          context is WebViewProvider ->
-            context.getCurrentWebView()?.title
-              ?: context.getString(R.string.no_section_info)
-
-          else -> context.getString(R.string.no_section_info)
-        }
-    }
-  }
-
-  class SectionTableDrawerViewHolder(private val sectionListBinding: SectionListBinding) :
-    BaseViewHolder<TableDrawerAdapter.DocumentSection>(sectionListBinding.root) {
-    override fun bind(
-      item: TableDrawerAdapter.DocumentSection
-    ) {
-      val context = itemView.context
-      val padding =
-        ((item.level - 1) * context.resources.getDimension(R.dimen.title_text_padding)).toInt()
-      sectionListBinding.titleText.setPadding(padding, 0, 0, 0)
-      sectionListBinding.titleText.text = item.title
-    }
-  }
-
-  data class DocumentSection(var title: String, var id: String, var level: Int)
-}

core/src/main/java/org/kiwix/kiwixmobile/core/main/reader/CoreReaderFragment.kt

@@ -474,7 +474,9 @@ abstract class CoreReaderFragment :
           },
           mainActivityBottomAppBarScrollBehaviour = (requireActivity() as CoreMainActivity).bottomAppBarScrollBehaviour,
           documentSections = documentSections,
-          showTableOfContentDrawer = shouldTableOfContentDrawer
+          showTableOfContentDrawer = shouldTableOfContentDrawer,
+          onUserBackPressed = { onUserBackPressed(requireActivity() as CoreMainActivity) },
+          navHostController = (requireActivity() as CoreMainActivity).navController
         )
         DialogHost(alertDialogShower as AlertDialogShower)
       }
@@ -842,9 +844,16 @@ abstract class CoreReaderFragment :
     shouldTableOfContentDrawer.update { true }
   }
 
-  @Suppress("ReturnCount", "NestedBlockDepth")
+  @Suppress("ReturnCount", "NestedBlockDepth", "LongMethod", "CyclomaticComplexMethod")
-  override fun onBackPressed(activity: AppCompatActivity): FragmentActivityExtensions.Super {
+  private fun onUserBackPressed(coreMainActivity: CoreMainActivity): FragmentActivityExtensions.Super {
     when {
+      coreMainActivity.leftDrawerState.isOpen -> {
+        coreMainActivity.uiCoroutineScope.launch {
+          coreMainActivity.leftDrawerState.close()
+        }
+        return FragmentActivityExtensions.Super.ShouldNotCall
+      }
+
       readerScreenState.value.showTabSwitcher -> {
         selectTab(
           if (currentWebViewIndex < webViewList.size) {
@@ -893,7 +902,12 @@ abstract class CoreReaderFragment :
             isHomePageOfServiceWorkerZimFiles(url, webViewBackWordHistoryList)
           ) {
             // If it is the last page that is showing to the user, then exit the application.
-            return@onBackPressed FragmentActivityExtensions.Super.ShouldCall
+            if (coreMainActivity.navController.previousBackStackEntry?.destination?.route !=
+              coreMainActivity.searchFragmentRoute
+            ) {
+              activity?.finish()
+            }
+            return FragmentActivityExtensions.Super.ShouldCall
           }
         }
         // Otherwise, go to the previous page.

core/src/main/java/org/kiwix/kiwixmobile/core/main/reader/ReaderScreen.kt

@@ -22,6 +22,7 @@ import android.view.View
 import android.view.ViewGroup
 import android.view.ViewGroup.LayoutParams.MATCH_PARENT
 import android.widget.FrameLayout
+import androidx.activity.compose.BackHandler
 import androidx.compose.animation.AnimatedVisibility
 import androidx.compose.animation.core.animateFloatAsState
 import androidx.compose.animation.core.tween
@@ -114,9 +115,11 @@ import androidx.compose.ui.unit.Dp
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.viewinterop.AndroidView
 import androidx.compose.ui.zIndex
+import androidx.navigation.NavHostController
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.launch
 import org.kiwix.kiwixmobile.core.R
+import org.kiwix.kiwixmobile.core.base.FragmentActivityExtensions
 import org.kiwix.kiwixmobile.core.downloader.downloadManager.HUNDERED
 import org.kiwix.kiwixmobile.core.downloader.downloadManager.ZERO
 import org.kiwix.kiwixmobile.core.extensions.update
@@ -177,13 +180,15 @@ const val READER_BOTTOM_BAR_TABLE_CONTENT_BUTTON_TESTING_TAG =
   "readerBottomBarTableContentButtonTestingTag"
 
 @OptIn(ExperimentalMaterial3Api::class)
-@Suppress("ComposableLambdaParameterNaming", "LongMethod")
+@Suppress("ComposableLambdaParameterNaming", "LongMethod", "LongParameterList")
 @Composable
 fun ReaderScreen(
   state: ReaderScreenState,
   actionMenuItems: List<ActionMenuItem>,
   showTableOfContentDrawer: MutableState<Boolean>,
   documentSections: MutableList<DocumentSection>?,
+  onUserBackPressed: () -> FragmentActivityExtensions.Super,
+  navHostController: NavHostController,
   mainActivityBottomAppBarScrollBehaviour: BottomAppBarScrollBehavior?,
   navigationIcon: @Composable () -> Unit
 ) {
@@ -215,6 +220,7 @@ fun ReaderScreen(
           }
           .semantics { testTag = READER_SCREEN_TESTING_TAG }
       ) { paddingValues ->
+        OnBackPressed(onUserBackPressed, navHostController)
         ReaderContentLayout(
           state,
           Modifier.padding(paddingValues),
@@ -251,6 +257,19 @@ fun ReaderScreen(
   }
 }
 
+@Composable
+fun OnBackPressed(
+  onUserBackPressed: () -> FragmentActivityExtensions.Super,
+  navHostController: NavHostController
+) {
+  BackHandler(enabled = true) {
+    val result = onUserBackPressed()
+    if (result == FragmentActivityExtensions.Super.ShouldCall) {
+      navHostController.popBackStack()
+    }
+  }
+}
+
 @OptIn(ExperimentalMaterial3Api::class)
 @Suppress("ComposableLambdaParameterNaming")
 @Composable
@@ -731,7 +750,8 @@ private fun BottomAppBarButtonIcon(
         onClick = onClick,
         onLongClick = onLongClick,
         enabled = shouldEnable
-      ).testTag(testingTag),
+      )
+      .testTag(testingTag),
     contentAlignment = Alignment.Center
   ) {
     Icon(

core/src/main/java/org/kiwix/kiwixmobile/core/search/SearchFragment.kt

@@ -22,7 +22,7 @@ import android.os.Bundle
 import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
-import androidx.activity.OnBackPressedCallback
+import androidx.compose.runtime.DisposableEffect
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.ui.platform.ComposeView
 import androidx.lifecycle.Lifecycle
@@ -39,6 +39,7 @@ import kotlinx.coroutines.withContext
 import org.kiwix.kiwixmobile.core.R
 import org.kiwix.kiwixmobile.core.base.BaseActivity
 import org.kiwix.kiwixmobile.core.base.BaseFragment
+import org.kiwix.kiwixmobile.core.base.FragmentActivityExtensions
 import org.kiwix.kiwixmobile.core.extensions.ActivityExtensions.cachedComponent
 import org.kiwix.kiwixmobile.core.extensions.closeKeyboard
 import org.kiwix.kiwixmobile.core.extensions.coreMainActivity
@@ -123,6 +124,12 @@ class SearchFragment : BaseFragment() {
     super.onViewCreated(view, savedInstanceState)
     composeView?.apply {
       setContent {
+        DisposableEffect(Unit) {
+          (activity as CoreMainActivity).customBackHandler.value = { handleBackPress() }
+          onDispose {
+            (activity as CoreMainActivity).customBackHandler.value = null
+          }
+        }
         SearchScreen(
           searchScreenState.value,
           actionMenuItems(),
@@ -134,7 +141,6 @@ class SearchFragment : BaseFragment() {
     searchViewModel.setAlertDialogShower(dialogShower as AlertDialogShower)
     observeViewModelData()
     handleSearchArgument()
-    handleBackPress()
   }
 
   private fun handleSearchArgument() {
@@ -203,15 +209,9 @@ class SearchFragment : BaseFragment() {
     }
   }
 
-  private fun handleBackPress() {
+  private fun handleBackPress(): FragmentActivityExtensions.Super {
-    activity?.onBackPressedDispatcher?.addCallback(
+    goBack()
-      viewLifecycleOwner,
+    return FragmentActivityExtensions.Super.ShouldCall
-      object : OnBackPressedCallback(true) {
-        override fun handleOnBackPressed() {
-          goBack()
-        }
-      }
-    )
   }
 
   override fun onDestroyView() {

custom/src/main/java/org/kiwix/kiwixmobile/custom/main/CustomMainActivity.kt

@@ -71,7 +71,9 @@ class CustomMainActivity : CoreMainActivity() {
         leftDrawerContent = leftDrawerMenu,
         topLevelDestinationsRoute = topLevelDestinationsRoute,
         leftDrawerState = leftDrawerState,
-        enableLeftDrawer = enableLeftDrawer.value
+        enableLeftDrawer = enableLeftDrawer.value,
+        uiCoroutineScope = uiCoroutineScope,
+        customBackHandler = customBackHandler
       )
       DialogHost(alertDialogShower)
     }

custom/src/main/java/org/kiwix/kiwixmobile/custom/main/CustomMainActivityScreen.kt

@@ -18,6 +18,8 @@
 
 package org.kiwix.kiwixmobile.custom.main
 
+import androidx.activity.compose.BackHandler
+import androidx.activity.compose.LocalActivity
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.fillMaxSize
@@ -27,10 +29,14 @@ import androidx.compose.material3.DrawerState
 import androidx.compose.material3.ModalNavigationDrawer
 import androidx.compose.material3.Scaffold
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.MutableState
 import androidx.compose.runtime.getValue
 import androidx.compose.ui.Modifier
 import androidx.navigation.NavHostController
 import androidx.navigation.compose.currentBackStackEntryAsState
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.launch
+import org.kiwix.kiwixmobile.core.base.FragmentActivityExtensions
 import org.kiwix.kiwixmobile.core.main.DrawerMenuGroup
 import org.kiwix.kiwixmobile.core.main.LeftDrawerMenu
 import org.kiwix.kiwixmobile.core.ui.theme.KiwixTheme
@@ -42,9 +48,18 @@ fun CustomMainActivityScreen(
   topLevelDestinationsRoute: Set<String>,
   leftDrawerState: DrawerState,
   enableLeftDrawer: Boolean,
+  customBackHandler: MutableState<(() -> FragmentActivityExtensions.Super)?>,
+  uiCoroutineScope: CoroutineScope
 ) {
   val navBackStackEntry by navController.currentBackStackEntryAsState()
   val currentRoute = navBackStackEntry?.destination?.route
+  OnUserBackPressed(
+    leftDrawerState,
+    uiCoroutineScope,
+    currentRoute,
+    navController,
+    customBackHandler
+  )
   KiwixTheme {
     ModalNavigationDrawer(
       drawerState = leftDrawerState,
@@ -76,3 +91,34 @@ fun CustomMainActivityScreen(
     }
   }
 }
+
+@Composable
+private fun OnUserBackPressed(
+  leftDrawerState: DrawerState,
+  uiCoroutineScope: CoroutineScope,
+  currentRoute: String?,
+  navController: NavHostController,
+  customBackHandler: MutableState<(() -> FragmentActivityExtensions.Super)?>,
+) {
+  val activity = LocalActivity.current
+  BackHandler(enabled = true) {
+    when {
+      leftDrawerState.isOpen -> uiCoroutineScope.launch { leftDrawerState.close() }
+      customBackHandler.value?.invoke() == FragmentActivityExtensions.Super.ShouldNotCall -> {
+        // do nothing since fragment handles the back press.
+      }
+
+      currentRoute == CustomDestination.Reader.route &&
+        navController.previousBackStackEntry?.destination?.route != CustomDestination.Search.route -> {
+        activity?.finish()
+      }
+
+      else -> {
+        val popped = navController.popBackStack()
+        if (!popped) {
+          activity?.finish()
+        }
+      }
+    }
+  }
+}