Fixed bugs and enhanced search functionality.

* A bug was introduced after enhancing the search functionality to align with the new `java-libkiwix` wrapper. Initially, when searching for any article in the ZIM file, the loading progress bar was not being displayed. This commit resolves this issue.
* While searching within large ZIM files, the application used to freeze momentarily due to fetching data from the `libkiwix` on the UI thread. We have improved this functionality to provide a seamless user experience.

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

@@ -40,7 +40,9 @@ import androidx.recyclerview.widget.LinearLayoutManager
 import androidx.recyclerview.widget.RecyclerView
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.Job
 import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
 import org.kiwix.kiwixmobile.core.R
 import org.kiwix.kiwixmobile.core.base.BaseActivity
 import org.kiwix.kiwixmobile.core.base.BaseFragment
@@ -82,6 +84,7 @@ class SearchFragment : BaseFragment() {
   private var searchAdapter: SearchAdapter? = null
   private var isDataLoading = false
   private var searchState: SearchState? = null
+  private var renderingJob: Job? = null
 
   override fun inject(baseActivity: BaseActivity) {
     baseActivity.cachedComponent.inject(this)
@@ -200,6 +203,8 @@ class SearchFragment : BaseFragment() {
 
   override fun onDestroyView() {
     super.onDestroyView()
+    renderingJob?.cancel()
+    renderingJob = null
     searchState = null
     activity?.intent?.action = null
     searchView = null
@@ -258,17 +263,24 @@ class SearchFragment : BaseFragment() {
     )
   }
 
-  private suspend fun render(state: SearchState) {
+  private fun render(state: SearchState) {
+    renderingJob?.cancel()
     isDataLoading = false
     searchState = state
     searchInTextMenuItem?.isVisible = state.searchOrigin == FromWebView
     searchInTextMenuItem?.isEnabled = state.searchTerm.isNotBlank()
-    fragmentSearchBinding?.searchLoadingIndicator?.isShowing(state.isLoading)
-    val searchResult = state.getVisibleResults(0)
-    fragmentSearchBinding?.searchNoResults?.isVisible =
-      searchResult?.isEmpty() == true
-    searchResult?.let {
-      searchAdapter?.items = it
+    fragmentSearchBinding?.searchLoadingIndicator?.isShowing(true)
+    renderingJob = CoroutineScope(Dispatchers.Main).launch {
+      val searchResult = withContext(Dispatchers.IO) {
+        state.getVisibleResults(0)
+      }
+
+      fragmentSearchBinding?.searchLoadingIndicator?.isShowing(false)
+
+      searchResult?.let {
+        fragmentSearchBinding?.searchNoResults?.isVisible = it.isEmpty()
+        searchAdapter?.items = it
+      }
     }
   }
 

core/src/main/java/org/kiwix/kiwixmobile/core/search/viewmodel/SearchState.kt

@@ -26,13 +26,10 @@ data class SearchState(
   val recentResults: List<SearchListItem.RecentSearchListItem>,
   val searchOrigin: SearchOrigin
 ) {
-  private var isDataLoading = false
-  suspend fun getVisibleResults(startIndex: Int): List<SearchListItem.RecentSearchListItem>? =
+  fun getVisibleResults(startIndex: Int): List<SearchListItem.RecentSearchListItem>? =
     if (searchTerm.isEmpty()) {
-      isDataLoading = false
       recentResults
     } else {
-      isDataLoading = true
       searchResultsWithTerm.suggestionSearch?.let {
         val maximumResults = it.estimatedMatches
         val safeEndIndex =
@@ -49,15 +46,13 @@ data class SearchState(
          * We check this in SearchFragment to avoid unnecessary data loading
          * while scrolling to the end of the list when there are no items available.
          */
-        isDataLoading = false
         searchResults.ifEmpty { null }
       } ?: kotlin.run {
-        isDataLoading = false
         recentResults
       }
     }
 
-  val isLoading get() = searchTerm != searchResultsWithTerm.searchTerm || isDataLoading
+  val isLoading = searchTerm != searchResultsWithTerm.searchTerm
 }
 
 enum class SearchOrigin {