#1676 Search is slow and laggy - add kotlin UDF implementation

app/src/main/java/org/kiwix/kiwixmobile/KiwixViewModelFactory.java

@@ -1,6 +1,6 @@
 /*
  * Kiwix Android
- * Copyright (c) 2019 Kiwix <android.kiwix.org>
+ * 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
@@ -27,7 +27,6 @@ import org.kiwix.kiwixmobile.di.KiwixScope;
 
 @KiwixScope
 public class KiwixViewModelFactory extends ViewModelFactory {
-
   @Inject
   public KiwixViewModelFactory(Map<Class<? extends ViewModel>, Provider<ViewModel>> creators) {
     super(creators);

app/src/main/java/org/kiwix/kiwixmobile/language/LanguageActivity.kt

@@ -32,6 +32,7 @@ import kotlinx.android.synthetic.main.activity_language.language_recycler_view
 import org.kiwix.kiwixmobile.R
 import org.kiwix.kiwixmobile.core.base.BaseActivity
 import org.kiwix.kiwixmobile.core.extensions.ActivityExtensions.viewModel
+import org.kiwix.kiwixmobile.core.utils.SimpleTextListener
 import org.kiwix.kiwixmobile.kiwixActivityComponent
 import org.kiwix.kiwixmobile.language.adapter.LanguageAdapter
 import org.kiwix.kiwixmobile.language.adapter.LanguageDelegate.HeaderDelegate
@@ -44,7 +45,6 @@ import org.kiwix.kiwixmobile.language.viewmodel.State
 import org.kiwix.kiwixmobile.language.viewmodel.State.Content
 import org.kiwix.kiwixmobile.language.viewmodel.State.Loading
 import org.kiwix.kiwixmobile.language.viewmodel.State.Saving
-import org.kiwix.kiwixmobile.zim_manager.SimpleTextListener
 import javax.inject.Inject
 
 class LanguageActivity : BaseActivity() {

app/src/main/java/org/kiwix/kiwixmobile/language/viewmodel/LanguageViewModel.kt

@@ -51,14 +51,17 @@ class LanguageViewModel @Inject constructor(
         .subscribe(state::postValue, Throwable::printStackTrace),
       languageDao.languages().filter { it.isNotEmpty() }
         .subscribe(
-          {
-            actions.offer(UpdateLanguages(it))
-          },
+          { actions.offer(UpdateLanguages(it)) },
           Throwable::printStackTrace
         )
     )
   }
 
+  override fun onCleared() {
+    compositeDisposable.clear()
+    super.onCleared()
+  }
+
   private fun reduce(
     action: Action,
     currentState: State

app/src/main/java/org/kiwix/kiwixmobile/zim_manager/ZimManageActivity.kt

@@ -32,6 +32,7 @@ import org.kiwix.kiwixmobile.core.dao.NewLanguagesDao
 import org.kiwix.kiwixmobile.core.extensions.ActivityExtensions.start
 import org.kiwix.kiwixmobile.core.extensions.ActivityExtensions.viewModel
 import org.kiwix.kiwixmobile.core.utils.LanguageUtils
+import org.kiwix.kiwixmobile.core.utils.SimpleTextListener
 import org.kiwix.kiwixmobile.kiwixActivityComponent
 import org.kiwix.kiwixmobile.language.LanguageActivity
 import org.kiwix.kiwixmobile.local_file_transfer.LocalFileTransferActivity

core/src/main/AndroidManifest.xml

@@ -23,7 +23,10 @@
     android:usesCleartextTraffic="true"
     tools:targetApi="m">
 
-    <activity android:name=".search.SearchActivity" />
+    <activity
+      android:name=".search.SearchActivity"
+      android:windowSoftInputMode="adjustResize" />
+
     <activity android:name=".bookmark.BookmarksActivity" />
 
     <provider

core/src/main/java/org/kiwix/kiwixmobile/core/ViewModelFactory.java

@@ -21,11 +21,15 @@ package org.kiwix.kiwixmobile.core;
 import androidx.lifecycle.ViewModel;
 import androidx.lifecycle.ViewModelProvider;
 import java.util.Map;
+import javax.inject.Inject;
 import javax.inject.Provider;
+import javax.inject.Singleton;
 
+@Singleton
 public class ViewModelFactory implements ViewModelProvider.Factory {
   private final Map<Class<? extends ViewModel>, Provider<ViewModel>> creators;
 
+  @Inject
   public ViewModelFactory(
     Map<Class<? extends ViewModel>, Provider<ViewModel>> creators) {
     this.creators = creators;

core/src/main/java/org/kiwix/kiwixmobile/core/dao/NewLanguagesDao.kt

@@ -19,6 +19,7 @@ package org.kiwix.kiwixmobile.core.dao
 
 import io.objectbox.Box
 import io.objectbox.kotlin.query
+import io.objectbox.query.Query
 import io.objectbox.rx.RxQuery
 import io.reactivex.BackpressureStrategy
 import io.reactivex.BackpressureStrategy.LATEST
@@ -40,5 +41,8 @@ class NewLanguagesDao @Inject constructor(private val box: Box<LanguageEntity>)
   }
 }
 
-internal fun <T> Box<T>.asFlowable(backpressureStrategy: BackpressureStrategy = LATEST) =
-  RxQuery.observable(query {}).toFlowable(backpressureStrategy)
+internal fun <T> Box<T>.asFlowable(
+  query: Query<T> = query {},
+  backpressureStrategy: BackpressureStrategy = LATEST
+) =
+  RxQuery.observable(query).toFlowable(backpressureStrategy)

core/src/main/java/org/kiwix/kiwixmobile/core/dao/NewRecentSearchDao.kt

@@ -22,28 +22,25 @@ import io.objectbox.kotlin.query
 import org.kiwix.kiwixmobile.core.dao.entities.RecentSearchEntity
 import org.kiwix.kiwixmobile.core.dao.entities.RecentSearchEntity_
 import org.kiwix.kiwixmobile.core.data.local.entity.RecentSearch
+import org.kiwix.kiwixmobile.core.search.adapter.SearchListItem.RecentSearchListItem
 import javax.inject.Inject
 
 class NewRecentSearchDao @Inject constructor(
   val box: Box<RecentSearchEntity>
 ) {
-  fun getRecentSearches(zimId: String?) = box
-    .query {
+  fun recentSearches(zimId: String?) = box.asFlowable(
+    box.query {
       equal(RecentSearchEntity_.zimId, zimId ?: "")
       orderDesc(RecentSearchEntity_.id)
     }
-    .find()
-    .distinctBy(RecentSearchEntity::searchTerm)
-    .take(NUM_RECENT_RESULTS)
-    .map(RecentSearchEntity::searchTerm)
+  ).map { searchEntities ->
+    searchEntities.distinct()
+      .take(NUM_RECENT_RESULTS)
+      .map { searchEntity -> RecentSearchListItem(searchEntity.searchTerm) }
+  }
 
   fun saveSearch(title: String, id: String) {
-    box.put(
-      RecentSearchEntity(
-        searchTerm = title,
-        zimId = id
-      )
-    )
+    box.put(RecentSearchEntity(searchTerm = title, zimId = id))
   }
 
   fun deleteSearchString(searchTerm: String) {

core/src/main/java/org/kiwix/kiwixmobile/core/di/components/CoreActivityComponent.kt

@@ -0,0 +1,42 @@
+/*
+ * 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.di.components
+
+import android.app.Activity
+import dagger.BindsInstance
+import dagger.Subcomponent
+import org.kiwix.kiwixmobile.core.di.ActivityScope
+import org.kiwix.kiwixmobile.core.di.modules.ActivityModule
+import org.kiwix.kiwixmobile.core.search.SearchActivity
+import org.kiwix.kiwixmobile.core.search.viewmodel.effects.ShowDeleteSearchDialog
+
+@ActivityScope
+@Subcomponent(modules = [ActivityModule::class])
+interface CoreActivityComponent {
+  fun inject(searchActivity: SearchActivity)
+  fun inject(showDeleteSearchDialog: ShowDeleteSearchDialog)
+
+  @Subcomponent.Builder
+  interface Builder {
+    @BindsInstance
+    fun activity(activity: Activity): CoreActivityComponent.Builder
+
+    fun build(): CoreActivityComponent
+  }
+}

core/src/main/java/org/kiwix/kiwixmobile/core/di/components/CoreComponent.kt

@@ -29,19 +29,21 @@ import org.kiwix.kiwixmobile.core.StorageObserver
 import org.kiwix.kiwixmobile.core.dao.FetchDownloadDao
 import org.kiwix.kiwixmobile.core.dao.NewBookDao
 import org.kiwix.kiwixmobile.core.dao.NewLanguagesDao
+import org.kiwix.kiwixmobile.core.dao.NewRecentSearchDao
 import org.kiwix.kiwixmobile.core.data.DataModule
 import org.kiwix.kiwixmobile.core.data.DataSource
 import org.kiwix.kiwixmobile.core.data.remote.KiwixService
 import org.kiwix.kiwixmobile.core.di.modules.ApplicationModule
+import org.kiwix.kiwixmobile.core.di.modules.CoreViewModelModule
 import org.kiwix.kiwixmobile.core.di.modules.JNIModule
 import org.kiwix.kiwixmobile.core.di.modules.NetworkModule
+import org.kiwix.kiwixmobile.core.di.modules.SearchModule
 import org.kiwix.kiwixmobile.core.downloader.Downloader
 import org.kiwix.kiwixmobile.core.main.AddNoteDialog
 import org.kiwix.kiwixmobile.core.main.KiwixWebView
 import org.kiwix.kiwixmobile.core.reader.ZimContentProvider
 import org.kiwix.kiwixmobile.core.reader.ZimFileReader
 import org.kiwix.kiwixmobile.core.reader.ZimReaderContainer
-import org.kiwix.kiwixmobile.core.search.AutoCompleteAdapter
 import org.kiwix.kiwixmobile.core.settings.CorePrefsFragment
 import org.kiwix.kiwixmobile.core.utils.BookUtils
 import org.kiwix.kiwixmobile.core.utils.SharedPreferenceUtil
@@ -53,7 +55,10 @@ import javax.inject.Singleton
     ApplicationModule::class,
     NetworkModule::class,
     JNIModule::class,
-    DataModule::class]
+    DataModule::class,
+    CoreViewModelModule::class,
+    SearchModule::class
+  ]
 )
 interface CoreComponent {
 
@@ -65,6 +70,7 @@ interface CoreComponent {
     fun build(): CoreComponent
   }
 
+  fun activityComponentBuilder(): CoreActivityComponent.Builder
   fun zimReaderContainer(): ZimReaderContainer
   fun sharedPrefUtil(): SharedPreferenceUtil
   fun zimFileReaderFactory(): ZimFileReader.Factory
@@ -76,6 +82,7 @@ interface CoreComponent {
   fun fetchDownloadDao(): FetchDownloadDao
   fun newBookDao(): NewBookDao
   fun newLanguagesDao(): NewLanguagesDao
+  fun recentSearchDao(): NewRecentSearchDao
   fun connectivityManager(): ConnectivityManager
   fun context(): Context
   fun downloader(): Downloader
@@ -85,7 +92,6 @@ interface CoreComponent {
   fun inject(zimContentProvider: ZimContentProvider)
   fun inject(kiwixWebView: KiwixWebView)
   fun inject(prefsFragment: CorePrefsFragment)
-  fun inject(autoCompleteAdapter: AutoCompleteAdapter)
   fun inject(storageSelectDialog: StorageSelectDialog)
   fun inject(addNoteDialog: AddNoteDialog)
 }

core/src/main/java/org/kiwix/kiwixmobile/core/di/modules/ActivityBindingModule.java

@@ -27,7 +27,6 @@ import org.kiwix.kiwixmobile.core.error.ErrorActivity;
 import org.kiwix.kiwixmobile.core.help.HelpActivity;
 import org.kiwix.kiwixmobile.core.history.HistoryActivity;
 import org.kiwix.kiwixmobile.core.history.HistoryModule;
-import org.kiwix.kiwixmobile.core.search.SearchActivity;
 
 /**
  * Dagger.Android annotation processor will create the sub-components. We also specify the modules
@@ -38,10 +37,6 @@ import org.kiwix.kiwixmobile.core.search.SearchActivity;
 @Module
 public abstract class ActivityBindingModule {
 
-  @ActivityScope
-  @ContributesAndroidInjector
-  public abstract SearchActivity provideSearchActivity();
-
   @ActivityScope
   @ContributesAndroidInjector(modules = BookmarksModule.class)
   public abstract BookmarksActivity provideBookmarksActivity();

core/src/main/java/org/kiwix/kiwixmobile/core/di/modules/CoreViewModelModule.kt

@@ -0,0 +1,42 @@
+/*
+ * 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.di.modules
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.ViewModelProvider
+import dagger.Binds
+import dagger.Module
+import dagger.multibindings.IntoMap
+import org.kiwix.kiwixmobile.core.ViewModelFactory
+import org.kiwix.kiwixmobile.core.di.ViewModelKey
+import org.kiwix.kiwixmobile.core.search.viewmodel.SearchViewModel
+import javax.inject.Singleton
+
+@Module
+abstract class CoreViewModelModule {
+  @Binds
+  @IntoMap
+  @ViewModelKey(SearchViewModel::class)
+  abstract fun bindSearchViewModel(searchViewModel: SearchViewModel): ViewModel
+
+  @Binds
+  @Singleton
+  abstract fun bindViewModelFactory(factory: ViewModelFactory):
+    ViewModelProvider.Factory
+}

core/src/main/java/org/kiwix/kiwixmobile/core/di/modules/SearchModule.kt

@@ -0,0 +1,31 @@
+/*
+ * 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.di.modules
+
+import dagger.Binds
+import dagger.Module
+import org.kiwix.kiwixmobile.core.search.viewmodel.SearchResultGenerator
+import org.kiwix.kiwixmobile.core.search.viewmodel.ZimSearchResultGenerator
+
+@Module
+abstract class SearchModule {
+  @Binds
+  abstract fun bindsSearchResultGenerator(zimSearchResultGenerator: ZimSearchResultGenerator):
+    SearchResultGenerator
+}

core/src/main/java/org/kiwix/kiwixmobile/core/extensions/ActivityExtensions.kt

@@ -28,6 +28,7 @@ import androidx.fragment.app.FragmentActivity
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.ViewModelProvider
 import androidx.lifecycle.ViewModelProviders
+import org.kiwix.kiwixmobile.core.CoreApp
 import org.kiwix.kiwixmobile.core.Intents
 
 object ActivityExtensions {
@@ -87,4 +88,7 @@ object ActivityExtensions {
   ) =
     ViewModelProviders.of(this, viewModelFactory)
       .get(T::class.java)
+
+  val Activity.coreActivityComponent
+    get() = CoreApp.getCoreComponent().activityComponentBuilder().activity(this).build()
 }

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

@@ -110,7 +110,7 @@ import static android.content.pm.PackageManager.PERMISSION_GRANTED;
 import static android.os.Build.VERSION_CODES;
 import static org.kiwix.kiwixmobile.core.main.TableDrawerAdapter.DocumentSection;
 import static org.kiwix.kiwixmobile.core.main.TableDrawerAdapter.TableClickListener;
-import static org.kiwix.kiwixmobile.core.search.SearchActivity.EXTRA_SEARCH_IN_TEXT;
+import static org.kiwix.kiwixmobile.core.search.viewmodel.effects.SearchInPreviousScreen.EXTRA_SEARCH_IN_TEXT;
 import static org.kiwix.kiwixmobile.core.utils.AnimationUtils.rotate;
 import static org.kiwix.kiwixmobile.core.utils.Constants.BOOKMARK_CHOSEN_REQUEST;
 import static org.kiwix.kiwixmobile.core.utils.Constants.EXTRA_CHOSE_X_TITLE;

core/src/main/java/org/kiwix/kiwixmobile/core/search/AutoCompleteAdapter.java

@@ -1,154 +0,0 @@
-/*
- * Kiwix Android
- * Copyright (c) 2019 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.search;
-
-import android.content.Context;
-import android.text.Html;
-import android.view.View;
-import android.view.ViewGroup;
-import android.widget.ArrayAdapter;
-import android.widget.Filter;
-import android.widget.Filterable;
-import android.widget.TextView;
-import java.util.ArrayList;
-import java.util.HashMap;
-import java.util.List;
-import javax.inject.Inject;
-import org.kiwix.kiwixlib.JNIKiwix;
-import org.kiwix.kiwixlib.JNIKiwixSearcher;
-import org.kiwix.kiwixmobile.core.CoreApp;
-import org.kiwix.kiwixmobile.core.utils.SharedPreferenceUtil;
-import org.kiwix.kiwixmobile.core.reader.ZimReaderContainer;
-
-public class AutoCompleteAdapter extends ArrayAdapter<String> implements Filterable {
-
-  @Inject JNIKiwix currentJNIReader;
-  @Inject SharedPreferenceUtil sharedPreferenceUtil;
-  @Inject ZimReaderContainer zimReaderContainer;
-  private List<String> mData;
-  private KiwixFilter mFilter;
-  private Context context;
-
-  public AutoCompleteAdapter(Context context) {
-    super(context, android.R.layout.simple_list_item_1);
-    this.context = context;
-    mData = new ArrayList<>();
-    mFilter = new KiwixFilter();
-    setupDagger();
-  }
-
-  private void setupDagger() {
-    CoreApp.getCoreComponent().inject(this);
-  }
-
-  @Override
-  public int getCount() {
-    return mData.size();
-  }
-
-  @Override
-  public View getView(int position, View convertView, ViewGroup parent) {
-    View row = super.getView(position, convertView, parent);
-
-    TextView tv = row.findViewById(android.R.id.text1);
-    tv.setText(Html.fromHtml(getItem(position)));
-
-    return row;
-  }
-
-  @Override
-  public String getItem(int index) {
-    String a = mData.get(index);
-    if (a.endsWith(".html")) {
-      String trim = a.substring(2);
-      trim = trim.substring(0, trim.length() - 5);
-      return trim.replace("_", " ");
-    } else {
-      return a;
-    }
-  }
-
-  @Override
-  public Filter getFilter() {
-    return mFilter;
-  }
-
-  class KiwixFilter extends Filter {
-
-    @Override
-    protected FilterResults performFiltering(CharSequence constraint) {
-      FilterResults filterResults = new FilterResults();
-      ArrayList<String> data = new ArrayList<>();
-
-      if (constraint != null) {
-        try {
-
-          /* Get search request */
-          final String query = constraint.toString();
-
-          /* Fulltext search */
-          if (sharedPreferenceUtil.getPrefFullTextSearch()) {
-            zimReaderContainer.search(query, 200);
-            JNIKiwixSearcher.Result result = zimReaderContainer.getNextResult();
-            while (result != null) {
-              if (!result.getTitle().trim().isEmpty()) {
-                data.add(result.getTitle());
-              }
-              result = zimReaderContainer.getNextResult();
-            }
-          }
-
-          /* Suggestion search if no fulltext results */
-          if (data.size() == 0) {
-            zimReaderContainer.searchSuggestions(query, 200);
-            String suggestion;
-            String suggestionUrl;
-            SearchSuggestion results;
-            List<String> alreadyAdded = new ArrayList<>();
-            while ((results = zimReaderContainer.getNextSuggestion()) != null) {
-                suggestion = results.getTitle();
-                suggestionUrl = results.getUrl();
-
-                if (!alreadyAdded.contains(suggestionUrl)) {
-                alreadyAdded.add(suggestionUrl);
-                data.add(suggestion);
-              }
-            }
-          }
-        } catch (Exception e) {
-          e.printStackTrace();
-        }
-
-        /* Return results */
-        filterResults.values = data;
-        filterResults.count = data.size();
-      }
-      return filterResults;
-    }
-
-    @Override
-    protected void publishResults(CharSequence contraint, FilterResults results) {
-      mData = (ArrayList<String>) results.values;
-      if (results.count > 0) {
-        notifyDataSetChanged();
-      } else {
-        notifyDataSetInvalidated();
-      }
-    }
-  }
-}

core/src/main/java/org/kiwix/kiwixmobile/core/search/SearchActivity.java

@@ -1,353 +0,0 @@
-/*
- * Kiwix Android
- * Copyright (c) 2019 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.search;
-
-import android.content.ActivityNotFoundException;
-import android.content.Intent;
-import android.os.Build;
-import android.os.Bundle;
-import android.provider.Settings;
-import android.speech.RecognizerIntent;
-import android.text.Html;
-import android.view.LayoutInflater;
-import android.view.Menu;
-import android.view.MenuItem;
-import android.view.View;
-import android.view.ViewGroup;
-import android.widget.AdapterView;
-import android.widget.ArrayAdapter;
-import android.widget.ListView;
-import android.widget.TextView;
-import android.widget.Toast;
-import androidx.annotation.NonNull;
-import androidx.annotation.Nullable;
-import androidx.appcompat.app.AlertDialog;
-import androidx.appcompat.widget.SearchView;
-import androidx.appcompat.widget.Toolbar;
-import androidx.core.view.ViewCompat;
-import java.util.ArrayList;
-import java.util.List;
-import java.util.Locale;
-import javax.inject.Inject;
-import org.kiwix.kiwixmobile.core.Intents;
-import org.kiwix.kiwixmobile.core.R;
-import org.kiwix.kiwixmobile.core.base.BaseActivity;
-import org.kiwix.kiwixmobile.core.main.CoreMainActivity;
-
-import static org.kiwix.kiwixmobile.core.utils.Constants.EXTRA_IS_WIDGET_VOICE;
-import static org.kiwix.kiwixmobile.core.utils.Constants.EXTRA_SEARCH;
-import static org.kiwix.kiwixmobile.core.utils.Constants.EXTRA_SEARCH_TEXT;
-import static org.kiwix.kiwixmobile.core.utils.Constants.TAG_FILE_SEARCHED;
-
-public class SearchActivity extends BaseActivity
-  implements AdapterView.OnItemClickListener, AdapterView.OnItemLongClickListener,
-  SearchViewCallback {
-
-  public static final String EXTRA_SEARCH_IN_TEXT = "bool_searchintext";
-
-  private final int REQ_CODE_SPEECH_INPUT = 100;
-  @Inject
-  SearchPresenter searchPresenter;
-  private ListView listView;
-  private ArrayAdapter<String> currentAdapter;
-  private AutoCompleteAdapter autoAdapter;
-  private ArrayAdapter<String> defaultAdapter;
-  private SearchView searchView;
-  private String searchText;
-
-  @Override
-  protected void onCreate(Bundle savedInstanceState) {
-    super.onCreate(savedInstanceState);
-    setContentView(R.layout.search);
-
-    if (savedInstanceState != null) {
-      searchText = savedInstanceState.getString(EXTRA_SEARCH_TEXT);
-    }
-    Toolbar toolbar = findViewById(R.id.toolbar);
-    ViewCompat.setLayoutDirection(toolbar, ViewCompat.LAYOUT_DIRECTION_LOCALE);
-    setSupportActionBar(toolbar);
-    getSupportActionBar().setHomeAsUpIndicator(R.drawable.ic_action_back);
-    getSupportActionBar().setHomeButtonEnabled(true);
-    searchPresenter.attachView(this);
-    listView = findViewById(R.id.search_list);
-    defaultAdapter = getDefaultAdapter();
-    searchPresenter.getRecentSearches();
-    activateDefaultAdapter();
-
-    autoAdapter = new AutoCompleteAdapter(this);
-    listView.setOnItemClickListener(this);
-    listView.setOnItemLongClickListener(this);
-
-    boolean IS_VOICE_SEARCH_INTENT = getIntent().getBooleanExtra(EXTRA_IS_WIDGET_VOICE, false);
-    if (IS_VOICE_SEARCH_INTENT) {
-      promptSpeechInput();
-    }
-  }
-
-  public void activateDefaultAdapter() {
-    currentAdapter = defaultAdapter;
-    listView.setAdapter(currentAdapter);
-  }
-
-  public void activateAutoAdapter() {
-    currentAdapter = autoAdapter;
-    listView.setAdapter(currentAdapter);
-  }
-
-  @Override
-  public void addRecentSearches(List<String> recentSearches) {
-    defaultAdapter.addAll(recentSearches);
-    defaultAdapter.notifyDataSetChanged();
-  }
-
-  @Override
-  public void finish() {
-    Toolbar toolbar = findViewById(R.id.toolbar);
-    setSupportActionBar(toolbar);
-    int value =
-      Settings.System.getInt(getContentResolver(), Settings.System.ALWAYS_FINISH_ACTIVITIES, 0);
-    if (value == 1) {
-      Intent intent = Intents.internal(CoreMainActivity.class);
-      startActivity(intent);
-    } else {
-      super.finish();
-      overridePendingTransition(android.R.anim.fade_in, android.R.anim.fade_out);
-    }
-  }
-
-  @Override
-  public boolean onCreateOptionsMenu(Menu menu) {
-    getMenuInflater().inflate(R.menu.menu_search, menu);
-    MenuItem searchMenuItem = menu.findItem(R.id.menu_search);
-    searchMenuItem.expandActionView();
-    searchView = (SearchView) menu.findItem(R.id.menu_search).getActionView();
-    searchView.setMaxWidth(Integer.MAX_VALUE);
-    if (searchText != null) {
-      searchView.setQuery(searchText, false);
-      activateAutoAdapter();
-      autoAdapter.getFilter().filter(searchText.toLowerCase());
-    }
-    searchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
-      @Override
-      public boolean onQueryTextSubmit(String s) {
-        return false;
-      }
-
-      @Override
-      public boolean onQueryTextChange(String s) {
-        if (s.equals("")) {
-          View item = findViewById(R.id.menu_searchintext);
-          item.setVisibility(View.VISIBLE);
-          activateDefaultAdapter();
-        } else {
-          View item = findViewById(R.id.menu_searchintext);
-          item.setVisibility(View.GONE);
-          activateAutoAdapter();
-          autoAdapter.getFilter().filter(s.toLowerCase());
-        }
-
-        return true;
-      }
-    });
-
-    searchMenuItem.setOnActionExpandListener(new MenuItem.OnActionExpandListener() {
-      @Override
-      public boolean onMenuItemActionExpand(MenuItem item) {
-        return false;
-      }
-
-      @Override
-      public boolean onMenuItemActionCollapse(MenuItem item) {
-        finish();
-        return false;
-      }
-    });
-
-    if (getIntent().hasExtra(Intent.EXTRA_PROCESS_TEXT)) {
-      searchView.setQuery(getIntent().getStringExtra(Intent.EXTRA_PROCESS_TEXT), true);
-    }
-
-    if (getIntent().hasExtra(EXTRA_SEARCH)) {
-      searchView.setQuery(getIntent().getStringExtra(EXTRA_SEARCH), true);
-    }
-
-    return true;
-  }
-
-  @Override
-  public boolean onOptionsItemSelected(MenuItem item) {
-    if (item.getItemId() == R.id.menu_searchintext) {
-      String queryText = "";
-      if (searchView != null) {
-        queryText = searchView.getQuery().toString();
-      }
-      Intent resultIntent = Intents.internal(CoreMainActivity.class);
-      resultIntent.putExtra(EXTRA_SEARCH_IN_TEXT, true);
-      resultIntent.putExtra(TAG_FILE_SEARCHED, queryText);
-      if (shouldStartNewActivity() != 1) {
-        setResult(RESULT_OK, resultIntent);
-        finish();
-      } else {
-        startActivity(resultIntent);
-      }
-      return true;
-    }
-    return super.onOptionsItemSelected(item);
-  }
-
-  @Override
-  public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
-    String title = currentAdapter.getItem(position);
-    searchPresenter.saveSearch(title);
-    sendMessage(title);
-  }
-
-  private void sendMessage(String uri) {
-    int value = shouldStartNewActivity();
-    if (value == 1) {
-      Intent i = Intents.internal(CoreMainActivity.class);
-      i.putExtra(TAG_FILE_SEARCHED, uri);
-      startActivity(i);
-    } else {
-      Intent i = new Intent();
-      i.putExtra(TAG_FILE_SEARCHED, uri);
-      setResult(RESULT_OK, i);
-      finish();
-    }
-  }
-
-  /**
-   * Checks if the ActivityManager is set to aggressively reclaim Activities.
-   *
-   * @return 1 if the above setting is true.
-   */
-  private int shouldStartNewActivity() {
-    int value;
-    if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN_MR1) {
-      //deprecated in API 17
-      value =
-        Settings.System.getInt(getContentResolver(), Settings.System.ALWAYS_FINISH_ACTIVITIES, 0);
-    } else {
-      value =
-        Settings.System.getInt(getContentResolver(), Settings.Global.ALWAYS_FINISH_ACTIVITIES, 0);
-    }
-    return value;
-  }
-
-  @Override
-  public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
-    if (parent.getAdapter() == defaultAdapter) {
-      String searched = listView.getItemAtPosition(position).toString();
-      deleteSpecificSearchDialog(searched);
-    }
-    return true;
-  }
-
-  private void deleteSpecificSearchDialog(final String search) {
-    new AlertDialog.Builder(this)
-      .setMessage(getString(R.string.delete_recent_search_item))
-      .setPositiveButton(getResources().getString(R.string.delete), (dialog, which) -> {
-        deleteSpecificSearchItem(search);
-        Toast.makeText(getBaseContext(),
-          getResources().getString(R.string.delete_specific_search_toast), Toast.LENGTH_SHORT)
-          .show();
-      })
-      .setNegativeButton(android.R.string.no, (dialog, which) -> {
-        // do nothing
-      })
-      .show();
-  }
-
-  private void deleteSpecificSearchItem(String search) {
-    searchPresenter.deleteSearchString(search);
-    resetAdapter();
-  }
-
-  private void resetAdapter() {
-    defaultAdapter = getDefaultAdapter();
-    activateDefaultAdapter();
-    searchPresenter.getRecentSearches();
-  }
-
-  private ArrayAdapter<String> getDefaultAdapter() {
-    return new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1) {
-      @NonNull
-      @Override
-      public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
-        View row;
-
-        if (convertView == null) {
-          row = LayoutInflater.from(parent.getContext())
-            .inflate(android.R.layout.simple_list_item_1, null);
-        } else {
-          row = convertView;
-        }
-
-        ((TextView) row).setText(Html.fromHtml(getItem(position)));
-        return row;
-      }
-    };
-  }
-
-  private void promptSpeechInput() {
-    String appName = getResources().getString(R.string.app_name);
-    Intent intent = new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH);
-    intent.putExtra(RecognizerIntent.EXTRA_LANGUAGE_MODEL,
-      RecognizerIntent.LANGUAGE_MODEL_FREE_FORM);
-    intent.putExtra(RecognizerIntent.EXTRA_LANGUAGE,
-      Locale.getDefault()); // TODO: choose selected lang on kiwix
-    intent.putExtra(RecognizerIntent.EXTRA_PROMPT,
-      String.format(getString(R.string.speech_prompt_text), appName));
-    try {
-      startActivityForResult(intent, REQ_CODE_SPEECH_INPUT);
-    } catch (ActivityNotFoundException a) {
-      Toast.makeText(getApplicationContext(),
-        getString(R.string.speech_not_supported),
-        Toast.LENGTH_SHORT).show();
-    }
-  }
-
-  @Override
-  protected void onActivityResult(int requestCode, int resultCode, Intent data) {
-    super.onActivityResult(requestCode, resultCode, data);
-
-    switch (requestCode) {
-
-      case REQ_CODE_SPEECH_INPUT: {
-        if (resultCode == RESULT_OK && data != null) {
-          ArrayList<String> result = data
-            .getStringArrayListExtra(RecognizerIntent.EXTRA_RESULTS);
-          searchViaVoice(result.get(0));
-        }
-        break;
-      }
-    }
-  }
-
-  private void searchViaVoice(String search) {
-    searchView.setQuery(search, false);
-  }
-
-  @Override
-  protected void onSaveInstanceState(Bundle outState) {
-    super.onSaveInstanceState(outState);
-    if (searchView != null && searchView.getQuery() != null) {
-      outState.putString(EXTRA_SEARCH_TEXT, searchView.getQuery().toString());
-    }
-  }
-}

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

@@ -0,0 +1,155 @@
+/*
+ * Kiwix Android
+ * Copyright (c) 2019 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.search
+
+import android.R.anim
+import android.content.Intent
+import android.os.Bundle
+import android.view.Menu
+import android.view.MenuItem
+import android.view.MenuItem.OnActionExpandListener
+import androidx.appcompat.widget.SearchView
+import androidx.lifecycle.Observer
+import androidx.lifecycle.ViewModelProvider
+import androidx.recyclerview.widget.LinearLayoutManager
+import androidx.recyclerview.widget.RecyclerView
+import io.reactivex.disposables.CompositeDisposable
+import kotlinx.android.synthetic.main.activity_search.searchViewAnimator
+import kotlinx.android.synthetic.main.activity_search.search_list
+import kotlinx.android.synthetic.main.layout_toolbar.toolbar
+import org.kiwix.kiwixmobile.core.R
+import org.kiwix.kiwixmobile.core.R.id
+import org.kiwix.kiwixmobile.core.base.BaseActivity
+import org.kiwix.kiwixmobile.core.extensions.ActivityExtensions.coreActivityComponent
+import org.kiwix.kiwixmobile.core.extensions.ActivityExtensions.viewModel
+import org.kiwix.kiwixmobile.core.extensions.setDistinctDisplayedChild
+import org.kiwix.kiwixmobile.core.search.adapter.SearchAdapter
+import org.kiwix.kiwixmobile.core.search.adapter.SearchDelegate.RecentSearchDelegate
+import org.kiwix.kiwixmobile.core.search.adapter.SearchDelegate.ZimSearchResultDelegate
+import org.kiwix.kiwixmobile.core.search.adapter.SearchListItem
+import org.kiwix.kiwixmobile.core.search.viewmodel.Action.ActivityResultReceived
+import org.kiwix.kiwixmobile.core.search.viewmodel.Action.ClickedSearchInText
+import org.kiwix.kiwixmobile.core.search.viewmodel.Action.CreatedWithIntent
+import org.kiwix.kiwixmobile.core.search.viewmodel.Action.ExitedSearch
+import org.kiwix.kiwixmobile.core.search.viewmodel.Action.Filter
+import org.kiwix.kiwixmobile.core.search.viewmodel.Action.OnItemClick
+import org.kiwix.kiwixmobile.core.search.viewmodel.Action.OnItemLongClick
+import org.kiwix.kiwixmobile.core.search.viewmodel.SearchViewModel
+import org.kiwix.kiwixmobile.core.search.viewmodel.State
+import org.kiwix.kiwixmobile.core.search.viewmodel.State.Empty
+import org.kiwix.kiwixmobile.core.search.viewmodel.State.Initialising
+import org.kiwix.kiwixmobile.core.search.viewmodel.State.Results
+import org.kiwix.kiwixmobile.core.utils.SimpleTextListener
+import javax.inject.Inject
+
+class SearchActivity : BaseActivity() {
+
+  val activityComponent by lazy { coreActivityComponent }
+  @Inject lateinit var viewModelFactory: ViewModelProvider.Factory
+
+  private lateinit var searchView: SearchView
+  private lateinit var searchInTextMenuItem: MenuItem
+
+  private val searchViewModel by lazy { viewModel<SearchViewModel>(viewModelFactory) }
+  private val compositeDisposable = CompositeDisposable()
+  private val searchAdapter: SearchAdapter by lazy {
+    SearchAdapter(
+      RecentSearchDelegate(::onItemClick) {
+        searchViewModel.actions.offer(OnItemLongClick(it))
+      },
+      ZimSearchResultDelegate(::onItemClick)
+    )
+  }
+
+  override fun injection() {
+    activityComponent.inject(this)
+  }
+
+  override fun onCreate(savedInstanceState: Bundle?) {
+    super.onCreate(savedInstanceState)
+    setContentView(R.layout.activity_search)
+    setSupportActionBar(toolbar)
+    supportActionBar!!.setHomeAsUpIndicator(R.drawable.ic_action_back)
+    supportActionBar!!.setHomeButtonEnabled(true)
+    search_list.run {
+      adapter = searchAdapter
+      layoutManager = LinearLayoutManager(context, RecyclerView.VERTICAL, false)
+      setHasFixedSize(true)
+    }
+    compositeDisposable.add(searchViewModel.effects.subscribe { it.invokeWith(this) })
+  }
+
+  override fun onDestroy() {
+    compositeDisposable.clear()
+    super.onDestroy()
+  }
+
+  override fun finish() {
+    super.finish()
+    overridePendingTransition(anim.fade_in, anim.fade_out)
+  }
+
+  override fun onCreateOptionsMenu(menu: Menu): Boolean {
+    menuInflater.inflate(R.menu.menu_search, menu)
+    val searchMenuItem = menu.findItem(id.menu_search)
+    searchMenuItem.expandActionView()
+    searchView = searchMenuItem.actionView as SearchView
+    searchView.setOnQueryTextListener(SimpleTextListener {
+      searchViewModel.actions.offer(Filter(it))
+    })
+    searchMenuItem.setOnActionExpandListener(object : OnActionExpandListener {
+      override fun onMenuItemActionExpand(item: MenuItem) = false
+
+      override fun onMenuItemActionCollapse(item: MenuItem): Boolean {
+        searchViewModel.actions.offer(ExitedSearch)
+        return false
+      }
+    })
+    searchInTextMenuItem = menu.findItem(R.id.menu_searchintext)
+    searchInTextMenuItem.setOnMenuItemClickListener {
+      searchViewModel.actions.offer(ClickedSearchInText)
+      true
+    }
+
+    searchViewModel.state.observe(this, Observer(::render))
+    searchViewModel.actions.offer(CreatedWithIntent(intent))
+    return true
+  }
+
+  private fun render(state: State) = when (state) {
+    is Results -> {
+      searchViewAnimator.setDistinctDisplayedChild(0)
+      searchAdapter.items = state.values
+      searchView.setQuery(state.searchString, false)
+      searchInTextMenuItem.isVisible = state.searchString.isNotBlank()
+    }
+    Empty -> searchViewAnimator.setDistinctDisplayedChild(1)
+    Initialising -> {
+      // do nothing
+    }
+  }
+
+  private fun onItemClick(it: SearchListItem) {
+    searchViewModel.actions.offer(OnItemClick(it))
+  }
+
+  override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
+    super.onActivityResult(requestCode, resultCode, data)
+    searchViewModel.actions.offer(ActivityResultReceived(requestCode, resultCode, data))
+  }
+}

core/src/main/java/org/kiwix/kiwixmobile/core/search/SearchPresenter.java

@@ -1,56 +0,0 @@
-/*
- * Kiwix Android
- * Copyright (c) 2019 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.search;
-
-import javax.inject.Inject;
-import org.kiwix.kiwixmobile.core.base.BasePresenter;
-import org.kiwix.kiwixmobile.core.dao.NewRecentSearchDao;
-import org.kiwix.kiwixmobile.core.reader.ZimReaderContainer;
-
-/**
- * Created by srv_twry on 14/2/18.
- */
-
-public class SearchPresenter extends BasePresenter<SearchViewCallback> {
-
-  private final NewRecentSearchDao recentSearchDao;
-  private final ZimReaderContainer zimReaderContainer;
-
-  @Inject SearchPresenter(NewRecentSearchDao recentSearchDao,
-    ZimReaderContainer zimReaderContainer) {
-    this.recentSearchDao = recentSearchDao;
-    this.zimReaderContainer = zimReaderContainer;
-  }
-
-  @Override
-  public void attachView(SearchViewCallback searchViewCallback) {
-    super.attachView(searchViewCallback);
-  }
-
-  void getRecentSearches() {
-    view.addRecentSearches(recentSearchDao.getRecentSearches(zimReaderContainer.getId()));
-  }
-
-  void saveSearch(String title) {
-    recentSearchDao.saveSearch(title, zimReaderContainer.getId());
-  }
-
-  void deleteSearchString(String search) {
-    recentSearchDao.deleteSearchString(search);
-  }
-}

core/src/main/java/org/kiwix/kiwixmobile/core/search/adapter/SearchAdapter.kt

@@ -0,0 +1,28 @@
+/*
+ * 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.search.adapter
+
+import org.kiwix.kiwixmobile.core.base.adapter.AdapterDelegate
+import org.kiwix.kiwixmobile.core.base.adapter.BaseDelegateAdapter
+
+class SearchAdapter(
+  vararg delegates: AdapterDelegate<SearchListItem>
+) : BaseDelegateAdapter<SearchListItem>(*delegates) {
+  override fun getIdFor(item: SearchListItem) = item.value.hashCode().toLong()
+}

core/src/main/java/org/kiwix/kiwixmobile/core/search/adapter/SearchDelegate.kt

@@ -0,0 +1,57 @@
+/*
+ * 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.search.adapter
+
+import android.view.ViewGroup
+import org.kiwix.kiwixmobile.core.base.adapter.AbsDelegateAdapter
+import org.kiwix.kiwixmobile.core.extensions.ViewGroupExtensions.inflate
+import org.kiwix.kiwixmobile.core.search.adapter.SearchListItem.RecentSearchListItem
+import org.kiwix.kiwixmobile.core.search.adapter.SearchListItem.ZimSearchResultListItem
+import org.kiwix.kiwixmobile.core.search.adapter.SearchViewHolder.RecentSearchViewHolder
+import org.kiwix.kiwixmobile.core.search.adapter.SearchViewHolder.ZimSearchResultViewHolder
+
+sealed class SearchDelegate<I : SearchListItem, out VH : SearchViewHolder<I>> :
+  AbsDelegateAdapter<I, SearchListItem, VH> {
+
+  class RecentSearchDelegate(
+    private val onClickListener: (SearchListItem) -> Unit,
+    private val onLongClickListener: (SearchListItem) -> Unit
+  ) : SearchDelegate<RecentSearchListItem, RecentSearchViewHolder>() {
+    override val itemClass = RecentSearchListItem::class.java
+
+    override fun createViewHolder(parent: ViewGroup) =
+      RecentSearchViewHolder(
+        parent.inflate(android.R.layout.simple_list_item_1, false),
+        onClickListener,
+        onLongClickListener
+      )
+  }
+
+  class ZimSearchResultDelegate(
+    private val onClickListener: (SearchListItem) -> Unit
+  ) : SearchDelegate<ZimSearchResultListItem, ZimSearchResultViewHolder>() {
+    override val itemClass = ZimSearchResultListItem::class.java
+
+    override fun createViewHolder(parent: ViewGroup) =
+      ZimSearchResultViewHolder(
+        parent.inflate(android.R.layout.simple_list_item_1, false),
+        onClickListener
+      )
+  }
+}

core/src/main/java/org/kiwix/kiwixmobile/core/search/adapter/SearchListItem.kt

@@ -0,0 +1,26 @@
+/*
+ * 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.search.adapter
+
+sealed class SearchListItem() {
+  abstract val value: String
+
+  data class RecentSearchListItem(override val value: String) : SearchListItem()
+  data class ZimSearchResultListItem constructor(override val value: String) : SearchListItem()
+}

core/src/main/java/org/kiwix/kiwixmobile/core/search/adapter/SearchViewHolder.kt

@@ -0,0 +1,54 @@
+/*
+ * 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.search.adapter
+
+import android.view.View
+import android.widget.TextView
+import org.kiwix.kiwixmobile.core.base.adapter.BaseViewHolder
+import org.kiwix.kiwixmobile.core.search.adapter.SearchListItem.RecentSearchListItem
+import org.kiwix.kiwixmobile.core.search.adapter.SearchListItem.ZimSearchResultListItem
+
+sealed class SearchViewHolder<in T : SearchListItem>(containerView: View) :
+  BaseViewHolder<T>(containerView) {
+
+  class RecentSearchViewHolder(
+    override val containerView: View,
+    private val onClickListener: (SearchListItem) -> Unit,
+    private val onLongClickListener: (SearchListItem) -> Unit
+  ) : SearchViewHolder<RecentSearchListItem>(containerView) {
+    override fun bind(item: RecentSearchListItem) {
+      containerView.setOnClickListener { onClickListener(item) }
+      containerView.setOnLongClickListener {
+        onLongClickListener(item)
+        true
+      }
+      (containerView as TextView).text = item.value
+    }
+  }
+
+  class ZimSearchResultViewHolder(
+    override val containerView: View,
+    private val onClickListener: (SearchListItem) -> Unit
+  ) : SearchViewHolder<ZimSearchResultListItem>(containerView) {
+    override fun bind(item: ZimSearchResultListItem) {
+      containerView.setOnClickListener { onClickListener(item) }
+      (containerView as TextView).text = item.value
+    }
+  }
+}

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

@@ -0,0 +1,37 @@
+/*
+ * 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.search.viewmodel
+
+import android.content.Intent
+import org.kiwix.kiwixmobile.core.search.adapter.SearchListItem
+
+sealed class Action {
+  object ExitedSearch : Action()
+  object ClickedSearchInText : Action()
+  object ReceivedPromptForSpeechInput : Action()
+  object StartSpechInputFailed : Action()
+
+  data class OnItemClick(val searchListItem: SearchListItem) : Action()
+  data class OnItemLongClick(val searchListItem: SearchListItem) : Action()
+  data class Filter(val term: String) : Action()
+  data class ConfirmedDelete(val searchListItem: SearchListItem) : Action()
+  data class CreatedWithIntent(val intent: Intent?) : Action()
+  data class ActivityResultReceived(val requestCode: Int, val resultCode: Int, val data: Intent?) :
+    Action()
+}

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

@@ -0,0 +1,54 @@
+/*
+ * 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.search.viewmodel
+
+import org.kiwix.kiwixmobile.core.reader.ZimReaderContainer
+import org.kiwix.kiwixmobile.core.search.adapter.SearchListItem
+import org.kiwix.kiwixmobile.core.search.adapter.SearchListItem.ZimSearchResultListItem
+import org.kiwix.kiwixmobile.core.utils.SharedPreferenceUtil
+import javax.inject.Inject
+
+interface SearchResultGenerator {
+  fun generateSearchResults(searchTerm: String): List<SearchListItem>
+}
+
+class ZimSearchResultGenerator @Inject constructor(
+  val sharedPreferenceUtil: SharedPreferenceUtil,
+  val zimReaderContainer: ZimReaderContainer
+) : SearchResultGenerator {
+  override fun generateSearchResults(searchTerm: String) =
+    if (searchTerm.isNotEmpty()) readResultsFromZim(searchTerm)
+    else emptyList()
+
+  private fun readResultsFromZim(it: String) =
+    if (sharedPreferenceUtil.prefFullTextSearch)
+      zimReaderContainer.search(it, 200).run { fullTextResults() }
+    else
+      zimReaderContainer.searchSuggestions(it, 200).run { suggestionResults() }
+
+  private fun suggestionResults() = generateSequence {
+    zimReaderContainer.getNextSuggestion()?.let { ZimSearchResultListItem(it.title) }
+  }.distinct()
+    .toList()
+
+  private fun fullTextResults() = generateSequence {
+    zimReaderContainer.getNextResult()?.let { ZimSearchResultListItem(it.title) }
+  }.filter { it.value.isNotBlank() }
+    .toList()
+}

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

@@ -0,0 +1,156 @@
+/*
+ * 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.search.viewmodel
+
+import androidx.lifecycle.MutableLiveData
+import androidx.lifecycle.ViewModel
+import io.reactivex.Flowable
+import io.reactivex.disposables.CompositeDisposable
+import io.reactivex.functions.Function3
+import io.reactivex.processors.BehaviorProcessor
+import io.reactivex.processors.PublishProcessor
+import io.reactivex.schedulers.Schedulers
+import org.kiwix.kiwixmobile.core.R.string
+import org.kiwix.kiwixmobile.core.base.SideEffect
+import org.kiwix.kiwixmobile.core.dao.NewRecentSearchDao
+import org.kiwix.kiwixmobile.core.reader.ZimReaderContainer
+import org.kiwix.kiwixmobile.core.search.adapter.SearchListItem
+import org.kiwix.kiwixmobile.core.search.viewmodel.Action.ActivityResultReceived
+import org.kiwix.kiwixmobile.core.search.viewmodel.Action.ClickedSearchInText
+import org.kiwix.kiwixmobile.core.search.viewmodel.Action.ConfirmedDelete
+import org.kiwix.kiwixmobile.core.search.viewmodel.Action.CreatedWithIntent
+import org.kiwix.kiwixmobile.core.search.viewmodel.Action.ExitedSearch
+import org.kiwix.kiwixmobile.core.search.viewmodel.Action.Filter
+import org.kiwix.kiwixmobile.core.search.viewmodel.Action.OnItemClick
+import org.kiwix.kiwixmobile.core.search.viewmodel.Action.OnItemLongClick
+import org.kiwix.kiwixmobile.core.search.viewmodel.Action.ReceivedPromptForSpeechInput
+import org.kiwix.kiwixmobile.core.search.viewmodel.Action.StartSpechInputFailed
+import org.kiwix.kiwixmobile.core.search.viewmodel.State.Empty
+import org.kiwix.kiwixmobile.core.search.viewmodel.State.Initialising
+import org.kiwix.kiwixmobile.core.search.viewmodel.State.Results
+import org.kiwix.kiwixmobile.core.search.viewmodel.effects.DeleteRecentSearch
+import org.kiwix.kiwixmobile.core.search.viewmodel.effects.Finish
+import org.kiwix.kiwixmobile.core.search.viewmodel.effects.OpenSearchItem
+import org.kiwix.kiwixmobile.core.search.viewmodel.effects.ProcessActivityResult
+import org.kiwix.kiwixmobile.core.search.viewmodel.effects.SaveSearchToRecents
+import org.kiwix.kiwixmobile.core.search.viewmodel.effects.SearchInPreviousScreen
+import org.kiwix.kiwixmobile.core.search.viewmodel.effects.SearchIntentProcessing
+import org.kiwix.kiwixmobile.core.search.viewmodel.effects.ShowDeleteSearchDialog
+import org.kiwix.kiwixmobile.core.search.viewmodel.effects.ShowToast
+import org.kiwix.kiwixmobile.core.search.viewmodel.effects.StartSpeechInput
+import java.util.concurrent.TimeUnit.MILLISECONDS
+import javax.inject.Inject
+
+class SearchViewModel @Inject constructor(
+  val recentSearchDao: NewRecentSearchDao,
+  val zimReaderContainer: ZimReaderContainer,
+  private val searchResultGenerator: SearchResultGenerator
+) : ViewModel() {
+
+  val state = MutableLiveData<State>().apply { value = Initialising }
+  val effects = PublishProcessor.create<SideEffect<*>>()
+  val actions = PublishProcessor.create<Action>()
+  private val filter = BehaviorProcessor.createDefault("")
+
+  private val compositeDisposable = CompositeDisposable()
+
+  init {
+    compositeDisposable.addAll(
+      viewStateReducer(),
+      actionMapper()
+    )
+  }
+
+  override fun onCleared() {
+    compositeDisposable.clear()
+    super.onCleared()
+  }
+
+  private fun actionMapper() = actions.map {
+    when (it) {
+      ExitedSearch -> effects.offer(Finish)
+      is OnItemClick -> saveSearchAndOpenItem(it)
+      is OnItemLongClick -> showDeleteDialog(it)
+      is Filter -> filter.offer(it.term)
+      ClickedSearchInText -> searchPreviousScreenhenStateIsValid()
+      is ConfirmedDelete -> deleteItemAndShowToast(it)
+      is CreatedWithIntent -> effects.offer(SearchIntentProcessing(it.intent, actions))
+      ReceivedPromptForSpeechInput -> effects.offer(StartSpeechInput(actions))
+      StartSpechInputFailed -> effects.offer(ShowToast(string.speech_not_supported))
+      is ActivityResultReceived ->
+        effects.offer(ProcessActivityResult(it.requestCode, it.resultCode, it.data, actions))
+    }
+  }.subscribe(
+    {},
+    Throwable::printStackTrace
+  )
+
+  private fun deleteItemAndShowToast(it: ConfirmedDelete) {
+    effects.offer(DeleteRecentSearch(it.searchListItem, recentSearchDao))
+    effects.offer(ShowToast(string.delete_specific_search_toast))
+  }
+
+  private fun searchPreviousScreenhenStateIsValid(): Any =
+    when (val currentState = state.value) {
+      is Results -> effects.offer(SearchInPreviousScreen(currentState.searchString))
+      else -> Unit
+    }
+
+  private fun showDeleteDialog(longClick: OnItemLongClick) {
+    effects.offer(ShowDeleteSearchDialog(longClick.searchListItem, actions))
+  }
+
+  private fun saveSearchAndOpenItem(it: OnItemClick) {
+    effects.offer(
+      SaveSearchToRecents(recentSearchDao, it.searchListItem, zimReaderContainer.id)
+    )
+    effects.offer(
+      OpenSearchItem(it.searchListItem)
+    )
+  }
+
+  private fun viewStateReducer() =
+    Flowable.combineLatest(
+      recentSearchDao.recentSearches(zimReaderContainer.id),
+      searchResultsFromZimReader(),
+      filter,
+      Function3(this::reduce)
+    ).debounce(100, MILLISECONDS)
+      .subscribe(state::postValue, Throwable::printStackTrace)
+
+  private fun reduce(
+    recentSearchResults: List<SearchListItem>,
+    zimSearchResults: List<SearchListItem>,
+    searchString: String
+  ) = when {
+    searchString.isNotEmpty() && zimSearchResults.isNotEmpty() ->
+      Results(searchString, zimSearchResults)
+    searchString.isEmpty() && recentSearchResults.isNotEmpty() ->
+      Results(searchString, recentSearchResults)
+    else -> Empty
+  }
+
+  private fun searchResultsFromZimReader() = filter
+    .distinctUntilChanged()
+    .switchMap(::searchResults)
+
+  private fun searchResults(it: String) = Flowable.fromCallable {
+    searchResultGenerator.generateSearchResults(it)
+  }.subscribeOn(Schedulers.io())
+}

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

@@ -0,0 +1,27 @@
+/*
+ * 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.search.viewmodel
+
+import org.kiwix.kiwixmobile.core.search.adapter.SearchListItem
+
+sealed class State {
+  data class Results(val searchString: String, val values: List<SearchListItem>) : State()
+  object Empty : State()
+  object Initialising : State()
+}

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

@@ -0,0 +1,33 @@
+/*
+ * 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.search.viewmodel.effects
+
+import androidx.appcompat.app.AppCompatActivity
+import org.kiwix.kiwixmobile.core.base.SideEffect
+import org.kiwix.kiwixmobile.core.dao.NewRecentSearchDao
+import org.kiwix.kiwixmobile.core.search.adapter.SearchListItem
+
+data class DeleteRecentSearch(
+  val searchListItem: SearchListItem,
+  val recentSearchDao: NewRecentSearchDao
+) : SideEffect<Unit> {
+  override fun invokeWith(activity: AppCompatActivity) {
+    recentSearchDao.deleteSearchString(searchListItem.value)
+  }
+}

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

@@ -1,6 +1,6 @@
 /*
  * Kiwix Android
- * Copyright (c) 2019 Kiwix <android.kiwix.org>
+ * 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
@@ -15,15 +15,14 @@
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  *
  */
-package org.kiwix.kiwixmobile.core.search;
 
-import java.util.List;
-import org.kiwix.kiwixmobile.core.base.BaseContract;
+package org.kiwix.kiwixmobile.core.search.viewmodel.effects
 
-/**
- * Created by srv_twry on 14/2/18.
- */
+import androidx.appcompat.app.AppCompatActivity
+import org.kiwix.kiwixmobile.core.base.SideEffect
 
-public interface SearchViewCallback extends BaseContract.View {
-  void addRecentSearches(List<String> recentSearches);
+object Finish : SideEffect<Unit> {
+  override fun invokeWith(activity: AppCompatActivity) {
+    activity.finish()
+  }
 }

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

@@ -0,0 +1,36 @@
+/*
+ * 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.search.viewmodel.effects
+
+import android.app.Activity
+import android.content.Intent
+import androidx.appcompat.app.AppCompatActivity
+import org.kiwix.kiwixmobile.core.base.SideEffect
+import org.kiwix.kiwixmobile.core.search.adapter.SearchListItem
+import org.kiwix.kiwixmobile.core.utils.Constants
+
+class OpenSearchItem(private val searchListItem: SearchListItem) : SideEffect<Unit> {
+  override fun invokeWith(activity: AppCompatActivity) {
+    activity.setResult(
+      Activity.RESULT_OK,
+      Intent().putExtra(Constants.TAG_FILE_SEARCHED, searchListItem.value)
+    )
+    activity.finish()
+  }
+}

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

@@ -0,0 +1,44 @@
+/*
+ * 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.search.viewmodel.effects
+
+import android.app.Activity
+import android.content.Intent
+import android.speech.RecognizerIntent
+import androidx.appcompat.app.AppCompatActivity
+import io.reactivex.processors.PublishProcessor
+import org.kiwix.kiwixmobile.core.base.SideEffect
+import org.kiwix.kiwixmobile.core.search.viewmodel.Action
+import org.kiwix.kiwixmobile.core.search.viewmodel.Action.Filter
+
+data class ProcessActivityResult(
+  val requestCode: Int,
+  val resultCode: Int,
+  val data: Intent?,
+  val actions: PublishProcessor<Action>
+) : SideEffect<Unit> {
+  override fun invokeWith(activity: AppCompatActivity) {
+    if (requestCode == StartSpeechInput.REQ_CODE_SPEECH_INPUT &&
+      resultCode == Activity.RESULT_OK &&
+      data != null
+    ) {
+      actions.offer(Filter(data.getStringArrayListExtra(RecognizerIntent.EXTRA_RESULTS)[0]))
+    }
+  }
+}

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

@@ -0,0 +1,34 @@
+/*
+ * 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.search.viewmodel.effects
+
+import androidx.appcompat.app.AppCompatActivity
+import org.kiwix.kiwixmobile.core.base.SideEffect
+import org.kiwix.kiwixmobile.core.dao.NewRecentSearchDao
+import org.kiwix.kiwixmobile.core.search.adapter.SearchListItem
+
+class SaveSearchToRecents(
+  private val recentSearchDao: NewRecentSearchDao,
+  private val searchListItem: SearchListItem,
+  private val id: String?
+) : SideEffect<Unit> {
+  override fun invokeWith(activity: AppCompatActivity) {
+    id?.let { recentSearchDao.saveSearch(searchListItem.value, it) }
+  }
+}

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

@@ -0,0 +1,42 @@
+/*
+ * 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.search.viewmodel.effects
+
+import android.app.Activity
+import android.content.Intent
+import androidx.appcompat.app.AppCompatActivity
+import org.kiwix.kiwixmobile.core.base.SideEffect
+import org.kiwix.kiwixmobile.core.utils.Constants
+
+data class SearchInPreviousScreen(val searchString: String) : SideEffect<Unit> {
+  override fun invokeWith(activity: AppCompatActivity) {
+    activity.setResult(
+      Activity.RESULT_OK,
+      Intent().apply {
+        putExtra(EXTRA_SEARCH_IN_TEXT, true)
+        putExtra(Constants.TAG_FILE_SEARCHED, searchString)
+      }
+    )
+    activity.finish()
+  }
+
+  companion object {
+    const val EXTRA_SEARCH_IN_TEXT = "bool_searchintext"
+  }
+}

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

@@ -0,0 +1,48 @@
+/*
+ * 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.search.viewmodel.effects
+
+import android.content.Intent
+import android.os.Build.VERSION
+import android.os.Build.VERSION_CODES
+import androidx.appcompat.app.AppCompatActivity
+import io.reactivex.processors.PublishProcessor
+import org.kiwix.kiwixmobile.core.base.SideEffect
+import org.kiwix.kiwixmobile.core.search.viewmodel.Action
+import org.kiwix.kiwixmobile.core.search.viewmodel.Action.Filter
+import org.kiwix.kiwixmobile.core.utils.Constants
+
+data class SearchIntentProcessing(
+  val intent: Intent?,
+  val actions: PublishProcessor<Action>
+) : SideEffect<Unit> {
+  override fun invokeWith(activity: AppCompatActivity) {
+    if (intent != null) {
+      if (VERSION.SDK_INT >= VERSION_CODES.M && intent.hasExtra(Intent.EXTRA_PROCESS_TEXT)) {
+        actions.offer(Filter(intent.getStringExtra(Intent.EXTRA_PROCESS_TEXT)))
+      }
+      if (intent.hasExtra(Constants.EXTRA_SEARCH)) {
+        actions.offer(Filter(intent.getStringExtra(Constants.EXTRA_SEARCH)))
+      }
+      if (intent.getBooleanExtra(Constants.EXTRA_IS_WIDGET_VOICE, false)) {
+        actions.offer(Action.ReceivedPromptForSpeechInput)
+      }
+    }
+  }
+}

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

@@ -0,0 +1,42 @@
+/*
+ * 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.search.viewmodel.effects
+
+import androidx.appcompat.app.AppCompatActivity
+import io.reactivex.processors.PublishProcessor
+import org.kiwix.kiwixmobile.core.base.SideEffect
+import org.kiwix.kiwixmobile.core.search.SearchActivity
+import org.kiwix.kiwixmobile.core.search.adapter.SearchListItem
+import org.kiwix.kiwixmobile.core.search.viewmodel.Action
+import org.kiwix.kiwixmobile.core.utils.DialogShower
+import org.kiwix.kiwixmobile.core.utils.KiwixDialog.DeleteSearch
+import javax.inject.Inject
+
+data class ShowDeleteSearchDialog(
+  val searchListItem: SearchListItem,
+  val actions: PublishProcessor<Action>
+) : SideEffect<Unit> {
+
+  @Inject lateinit var dialogShower: DialogShower
+
+  override fun invokeWith(activity: AppCompatActivity) {
+    (activity as SearchActivity).activityComponent.inject(this)
+    dialogShower.show(DeleteSearch, { actions.offer(Action.ConfirmedDelete(searchListItem)) })
+  }
+}

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

@@ -0,0 +1,31 @@
+/*
+ * 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.search.viewmodel.effects
+
+import android.widget.Toast
+import androidx.annotation.StringRes
+import androidx.appcompat.app.AppCompatActivity
+import org.kiwix.kiwixmobile.core.base.SideEffect
+import org.kiwix.kiwixmobile.core.extensions.toast
+
+data class ShowToast(@StringRes val stringId: Int) : SideEffect<Unit> {
+  override fun invokeWith(activity: AppCompatActivity) {
+    activity.toast(stringId, Toast.LENGTH_SHORT)
+  }
+}

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

@@ -0,0 +1,54 @@
+/*
+ * 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.search.viewmodel.effects
+
+import android.content.ActivityNotFoundException
+import android.content.Intent
+import android.speech.RecognizerIntent
+import androidx.appcompat.app.AppCompatActivity
+import io.reactivex.processors.PublishProcessor
+import org.kiwix.kiwixmobile.core.R
+import org.kiwix.kiwixmobile.core.base.SideEffect
+import org.kiwix.kiwixmobile.core.search.viewmodel.Action
+import java.util.Locale
+
+data class StartSpeechInput(val actions: PublishProcessor<Action>) : SideEffect<Unit> {
+
+  override fun invokeWith(activity: AppCompatActivity) {
+    try {
+      activity.startActivityForResult(
+        Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH).apply {
+          putExtra(RecognizerIntent.EXTRA_LANGUAGE_MODEL, RecognizerIntent.LANGUAGE_MODEL_FREE_FORM)
+          putExtra(RecognizerIntent.EXTRA_LANGUAGE, Locale.getDefault())
+          putExtra(
+            RecognizerIntent.EXTRA_PROMPT,
+            activity.getString(R.string.speech_prompt_text, activity.getString(R.string.app_name))
+          )
+        },
+        REQ_CODE_SPEECH_INPUT
+      )
+    } catch (a: ActivityNotFoundException) {
+      actions.offer(Action.StartSpechInputFailed)
+    }
+  }
+
+  companion object {
+    const val REQ_CODE_SPEECH_INPUT = 100
+  }
+}

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

@@ -99,6 +99,10 @@ sealed class KiwixDialog(
     constructor(selectedPeerDeviceName: String) : this(listOf(selectedPeerDeviceName))
   }
 
+  object DeleteSearch : KiwixDialog(
+    null, R.string.delete_recent_search_item, R.string.delete, R.string.no
+  )
+
   open class YesNoDialog(
     title: Int,
     message: Int

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

@@ -1,6 +1,6 @@
 /*
  * Kiwix Android
- * Copyright (c) 2019 Kiwix <android.kiwix.org>
+ * 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
@@ -16,7 +16,7 @@
  *
  */
 
-package org.kiwix.kiwixmobile.zim_manager
+package org.kiwix.kiwixmobile.core.utils
 
 import androidx.appcompat.widget.SearchView.OnQueryTextListener
 

core/src/main/res/layout/activity_search.xml

@@ -1,9 +1,7 @@
 <androidx.coordinatorlayout.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
-  xmlns:app="http://schemas.android.com/apk/res-auto"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   android:fitsSystemWindows="true"
-  android:layoutDirection="ltr"
   android:orientation="vertical">
 
   <LinearLayout
@@ -18,10 +16,25 @@
       <include layout="@layout/layout_toolbar" />
     </RelativeLayout>
 
-    <ListView
-      android:id="@+id/search_list"
+    <ViewAnimator
+      android:id="@+id/searchViewAnimator"
       android:layout_width="match_parent"
-      android:layout_height="match_parent" />
+      android:layout_height="match_parent"
+      android:animateLayoutChanges="true">
+
+      <androidx.recyclerview.widget.RecyclerView
+        android:id="@+id/search_list"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent" />
+
+      <TextView
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_gravity="center"
+        android:text="@string/no_results"
+        android:textAppearance="?textAppearanceHeadline6" />
+
+    </ViewAnimator>
 
   </LinearLayout>
 

core/src/main/res/layout/layout_toolbar.xml

@@ -9,5 +9,5 @@
     android:layout_height="wrap_content"
     app:popupTheme="@style/KiwixTheme"
     app:theme="@style/ThemeOverlay.MaterialComponents.Dark.ActionBar"
-    tools:showIn="@layout/search" />
+    tools:showIn="@layout/activity_search" />
 </merge>

core/src/main/res/values/strings.xml

@@ -292,6 +292,7 @@
   <string name="storage_permission_denied">Storage Permission Denied</string>
   <string name="grant_read_storage_permission">This app requires the ability to read storage to function. Please grant the permission in your settings</string>
   <string name="go_to_permissions">Go to Settings</string>
+  <string name="no_results">No Results</string>
   <string-array name="pref_night_modes_entries">
     <item>On</item>
     <item>Off</item>

custom/src/main/java/org/kiwix/kiwixmobile/custom/CustomViewModelFactory.java

@@ -1,6 +1,6 @@
 /*
  * Kiwix Android
- * Copyright (c) 2019 Kiwix <android.kiwix.org>
+ * 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
@@ -27,7 +27,6 @@ import org.kiwix.kiwixmobile.custom.di.CustomScope;
 
 @CustomScope
 public class CustomViewModelFactory extends ViewModelFactory {
-
   @Inject
   public CustomViewModelFactory(Map<Class<? extends ViewModel>, Provider<ViewModel>> creators) {
     super(creators);