Fixed: When opening the search from widget or from outside the application then search is broken with large ZIM files.

* Fixed: When launching the app fresh (cold start), the search screen could appear before the ZIM file was ready (because ZIM file loading in the reader happens on the IO thread), resulting in no search results. Now, incoming actions are delayed until the ZIM file finishes loading so that search works correctly.
* Fixed: Multiple fragment instances were created when repeatedly opening different fragments via bottomAppBar buttons, causing the back button to bring them to the foreground one by one instead of expected behavior.

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

@@ -43,6 +43,7 @@ import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.semantics.semantics
 import androidx.compose.ui.semantics.testTag
 import androidx.navigation.NavBackStackEntry
+import androidx.navigation.NavGraph.Companion.findStartDestination
 import androidx.navigation.NavHostController
 import androidx.navigation.compose.currentBackStackEntryAsState
 import kotlinx.coroutines.CoroutineScope
@@ -189,11 +190,20 @@ fun BottomNavigationBar(
       NavigationBarItem(
         selected = currentDestinationRoute == item.route,
         onClick = {
-          // Do not load again fragment that is already loaded.
-          if (item.route == currentDestinationRoute) return@NavigationBarItem
           uiCoroutineScope.launch {
             leftDrawerState.close()
-            navController.navigate(item.route)
+            navController.navigate(item.route) {
+              // Avoid multiple copies of the same destination
+              launchSingleTop = true
+
+              // Pop up to the start destination of the graph to avoid building up a large stack
+              popUpTo(navController.graph.findStartDestination().id) {
+                saveState = true
+              }
+
+              // Restore state when reselecting a previously selected tab
+              restoreState = true
+            }
           }
         },
         icon = {

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

@@ -338,6 +338,13 @@ abstract class CoreReaderFragment :
       return readerLifeCycleScope
     }
 
+  /**
+   * Handles actions that require the ZIM file to be fully loaded in the reader
+   * before opening the search screen. The search screen depends on the ZIM file,
+   * as its results come from the ZimFileReader.
+   */
+  private var pendingIntent: Intent? = null
+
   private var storagePermissionForNotesLauncher: ActivityResultLauncher<String>? =
     registerForActivityResult(
       ActivityResultContracts.RequestPermission()
@@ -1073,6 +1080,7 @@ abstract class CoreReaderFragment :
     super.onDestroyView()
     findInPageTitle = null
     searchItemToOpen = null
+    pendingIntent = null
     try {
       coreReaderLifeCycleScope?.cancel()
       readerLifeCycleScope?.cancel()
@@ -1907,12 +1915,15 @@ abstract class CoreReaderFragment :
     requireActivity().consumeObservable<SearchItemToOpen>(TAG_FILE_SEARCHED)
   }
 
-  private fun handleIntentActions(intent: Intent) {
-    Log.d(TAG_KIWIX, "action" + requireActivity().intent?.action)
-    startIntentBasedOnAction(intent)
+  private fun handlePendingIntent() {
+    pendingIntent?.let {
+      startIntentBasedOnAction(it)
+    }
+    pendingIntent = null
   }
 
   private fun startIntentBasedOnAction(intent: Intent?) {
+    Log.d(TAG_KIWIX, "action" + requireActivity().intent?.action)
     when (intent?.action) {
       Intent.ACTION_PROCESS_TEXT -> {
         goToSearchWithText(intent)
@@ -1981,7 +1992,7 @@ abstract class CoreReaderFragment :
     intent: Intent,
     activity: AppCompatActivity
   ): FragmentActivityExtensions.Super {
-    handleIntentActions(intent)
+    pendingIntent = intent
     return FragmentActivityExtensions.Super.ShouldCall
   }
 
@@ -2483,6 +2494,8 @@ abstract class CoreReaderFragment :
       }
       if (webViewHistoryList.isEmpty()) {
         restoreViewStateOnInvalidWebViewHistory()
+        // handle the pending intent if any present.
+        handlePendingIntent()
         return
       }
       restoreViewStateOnValidWebViewHistory(
@@ -2499,6 +2512,7 @@ abstract class CoreReaderFragment :
         searchItemToOpen = null
         findInPageTitle?.let(::findInPage)
         findInPageTitle = null
+        handlePendingIntent()
       }
     } catch (e: Exception) {
       Log.e(
@@ -2506,6 +2520,8 @@ abstract class CoreReaderFragment :
         "Could not restore tabs. Original exception = ${e.printStackTrace()}"
       )
       restoreViewStateOnInvalidWebViewHistory()
+      // handle the pending intent if any present.
+      handlePendingIntent()
     }
   }