Merge remote-tracking branch 'origin/develop' into new-translations

app/build.gradle

@@ -226,20 +226,13 @@ android {
   testBuildType "debug"
 
   lintOptions {
-    // Treat lint seriously
     abortOnError true
-    // Hardcoded strings in xml
+    checkAllWarnings true
-    error "HardcodedText"
+    warningsAsErrors true
-    // Hardcoded strings in setText
+    ignore 'MissingTranslation' //TODO stop ignoring
-    error "SetTextI18n"
+    baseline file("lint-baseline.xml")
-    // Strings.xml issues
-    warning "ExtraTranslation"
-    warning "MissingTranslation"
-
-    // Warnings
-    warning "InvalidPackage"
-    warning "StringFormatInvalid"
   }
+
   testOptions {
     unitTests.returnDefaultValues = true
     unitTests.all {

app/objectbox-models/default.json.bak

@@ -218,7 +218,7 @@
         },
         {
           "id": "2:6862771806221961183",
-          "name": "zimID"
+          "name": "zimId"
         },
         {
           "id": "3:4312769031500860715",

app/src/main/java/org/kiwix/kiwixmobile/di/components/ActivityComponent.kt

@@ -23,6 +23,7 @@ import dagger.Subcomponent
 import org.kiwix.kiwixmobile.di.modules.ActivityModule
 import org.kiwix.kiwixmobile.downloader.DownloadFragment
 import org.kiwix.kiwixmobile.zim_manager.fileselect_view.ZimFileSelectFragment
+import org.kiwix.kiwixmobile.zim_manager.fileselect_view.effects.DeleteFiles
 import org.kiwix.kiwixmobile.zim_manager.library_view.LibraryFragment
 
 @Subcomponent(modules = [ActivityModule::class])
@@ -33,6 +34,8 @@ interface ActivityComponent {
 
   fun inject(zimFileSelectFragment: ZimFileSelectFragment)
 
+  fun inject(deleteFiles: DeleteFiles)
+
   @Subcomponent.Builder
   interface Builder {
 

app/src/main/java/org/kiwix/kiwixmobile/downloader/model/DownloadModel.kt

@@ -18,10 +18,13 @@
 package org.kiwix.kiwixmobile.downloader.model
 
 import org.kiwix.kiwixmobile.library.entity.LibraryNetworkEntity.Book
+import org.kiwix.kiwixmobile.utils.StorageUtils
 
 data class DownloadModel(
   val databaseId: Long? = null,
-  val downloadId: Long ,
+  val downloadId: Long,
   val book: Book
-)
+) {
+  val fileNameFromUrl: String get() = StorageUtils.getFileNameFromUrl(book.url)
+}
 

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

@@ -0,0 +1,43 @@
+package org.kiwix.kiwixmobile.extensions
+
+import android.app.Activity
+import android.view.ActionMode
+import android.view.ActionMode.Callback
+import android.view.Menu
+import android.view.MenuItem
+
+fun Activity.startActionMode(
+  menuId: Int,
+  idsToClickActions: Map<Int, () -> Any>,
+  onDestroyAction: () -> Unit
+): ActionMode? {
+  return startActionMode(object : Callback {
+    override fun onActionItemClicked(
+      mode: ActionMode,
+      item: MenuItem
+    ) = idsToClickActions[item.itemId]?.let {
+      it()
+      mode.finish()
+      true
+    } ?: false
+
+    override fun onCreateActionMode(
+      mode: ActionMode,
+      menu: Menu?
+    ): Boolean {
+      mode.getMenuInflater()
+          .inflate(menuId, menu)
+      return true
+    }
+
+    override fun onPrepareActionMode(
+      mode: ActionMode?,
+      menu: Menu?
+    ) = false
+
+    override fun onDestroyActionMode(mode: ActionMode?) {
+      onDestroyAction()
+    }
+
+  })
+}

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

@@ -37,7 +37,6 @@ import android.net.Uri;
 import android.os.Build;
 import android.os.Bundle;
 import android.os.CountDownTimer;
-import android.os.Environment;
 import android.os.Handler;
 import android.provider.Settings;
 import android.text.SpannableString;
@@ -84,10 +83,10 @@ import com.google.android.material.appbar.AppBarLayout;
 import com.google.android.material.floatingactionbutton.FloatingActionButton;
 import com.google.android.material.navigation.NavigationView;
 import com.google.android.material.snackbar.Snackbar;
+import io.reactivex.android.schedulers.AndroidSchedulers;
 import java.io.File;
 import java.text.SimpleDateFormat;
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.Date;
 import java.util.List;
 import java.util.Locale;
@@ -100,20 +99,18 @@ import org.kiwix.kiwixmobile.base.BaseActivity;
 import org.kiwix.kiwixmobile.bookmark.BookmarkItem;
 import org.kiwix.kiwixmobile.bookmark.BookmarksActivity;
 import org.kiwix.kiwixmobile.data.ZimContentProvider;
-import org.kiwix.kiwixmobile.data.local.entity.Bookmark;
 import org.kiwix.kiwixmobile.help.HelpActivity;
 import org.kiwix.kiwixmobile.history.HistoryActivity;
 import org.kiwix.kiwixmobile.history.HistoryListItem;
-import org.kiwix.kiwixmobile.library.entity.LibraryNetworkEntity;
 import org.kiwix.kiwixmobile.search.SearchActivity;
 import org.kiwix.kiwixmobile.settings.KiwixSettingsActivity;
 import org.kiwix.kiwixmobile.utils.DimenUtils;
 import org.kiwix.kiwixmobile.utils.LanguageUtils;
 import org.kiwix.kiwixmobile.utils.NetworkUtils;
 import org.kiwix.kiwixmobile.utils.StyleUtils;
-import org.kiwix.kiwixmobile.utils.files.FileSearch;
 import org.kiwix.kiwixmobile.utils.files.FileUtils;
 import org.kiwix.kiwixmobile.zim_manager.ZimManageActivity;
+import org.kiwix.kiwixmobile.zim_manager.fileselect_view.StorageObserver;
 import org.kiwix.kiwixmobile.zim_manager.fileselect_view.adapter.BookOnDiskDelegate;
 import org.kiwix.kiwixmobile.zim_manager.fileselect_view.adapter.BooksOnDiskAdapter;
 import org.kiwix.kiwixmobile.zim_manager.fileselect_view.adapter.BooksOnDiskListItem;
@@ -201,14 +198,18 @@ public class MainActivity extends BaseActivity implements WebViewCallback,
   ImageView bottomToolbarArrowBack;
   @BindView(R.id.bottom_toolbar_arrow_forward)
   ImageView bottomToolbarArrowForward;
-  @Inject
-  MainContract.Presenter presenter;
   @BindView(R.id.tab_switcher_recycler_view)
   RecyclerView tabRecyclerView;
   @BindView(R.id.activity_main_tab_switcher)
   View tabSwitcherRoot;
   @BindView(R.id.tab_switcher_close_all_tabs)
   FloatingActionButton closeAllTabsButton;
+
+  @Inject
+  MainContract.Presenter presenter;
+  @Inject
+  StorageObserver storageObserver;
+
   private CountDownTimer hideBackToTopTimer = new CountDownTimer(1200, 1200) {
     @Override
     public void onTick(long millisUntilFinished) {
@@ -274,21 +275,7 @@ public class MainActivity extends BaseActivity implements WebViewCallback,
       closeTab(viewHolder.getAdapterPosition());
     }
   };
-  private FileSearch fileSearch =
-      new FileSearch(this, Collections.emptyList(), new FileSearch.ResultListener() {
-        final List<BooksOnDiskListItem.BookOnDisk> newBooks = new ArrayList<>();
 
-        @Override public void onBookFound(BooksOnDiskListItem.BookOnDisk bookOnDisk) {
-          runOnUiThread(() -> {
-              newBooks.add(bookOnDisk);
-          });
-        }
-
-        @Override
-        public void onScanCompleted() {
-          presenter.saveBooks(newBooks);
-        }
-      });
 
   private static void updateWidgets(Context context) {
     Intent intent = new Intent(context.getApplicationContext(), KiwixSearchWidget.class);
@@ -377,6 +364,7 @@ public class MainActivity extends BaseActivity implements WebViewCallback,
              open(bookOnDiskItem);
              return Unit.INSTANCE;
            },
+           null,
            null),
         BookOnDiskDelegate.LanguageDelegate.INSTANCE
     );
@@ -739,7 +727,6 @@ public class MainActivity extends BaseActivity implements WebViewCallback,
     downloadBookButton = null;
     hideBackToTopTimer.cancel();
     hideBackToTopTimer = null;
-    fileSearch = null;
     // TODO create a base Activity class that class this.
     FileUtils.deleteCachedFiles(this);
     tts.shutdown();
@@ -1199,7 +1186,7 @@ public class MainActivity extends BaseActivity implements WebViewCallback,
       case REQUEST_READ_STORAGE_PERMISSION: {
         if (grantResults.length > 0
             && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
-          fileSearch.scan(sharedPreferenceUtil.getPrefStorage());
+          scanStorageForZims();
         } else {
           Snackbar.make(drawerLayout, R.string.request_storage, Snackbar.LENGTH_LONG)
               .setAction(R.string.menu_settings, view -> {
@@ -1228,6 +1215,13 @@ public class MainActivity extends BaseActivity implements WebViewCallback,
     }
   }
 
+  private void scanStorageForZims() {
+    storageObserver.getBooksOnFileSystem()
+        .take(1)
+        .observeOn(AndroidSchedulers.mainThread())
+        .subscribe(presenter::saveBooks, Throwable::printStackTrace);
+  }
+
   // Workaround for popup bottom menu on older devices
   private void StyleMenuButtons(Menu m) {
     // Find each menu item and set its text colour
@@ -2105,7 +2099,7 @@ public class MainActivity extends BaseActivity implements WebViewCallback,
 
   @Override
   public void addBooks(List<BooksOnDiskListItem> books) {
-    booksAdapter.setItemList(books);
+    booksAdapter.setItems(books);
   }
 
   private void searchFiles() {
@@ -2116,7 +2110,7 @@ public class MainActivity extends BaseActivity implements WebViewCallback,
           new String[] { Manifest.permission.READ_EXTERNAL_STORAGE },
           REQUEST_READ_STORAGE_PERMISSION);
     } else {
-      fileSearch.scan(sharedPreferenceUtil.getPrefStorage());
+      scanStorageForZims();
     }
   }
 

app/src/main/java/org/kiwix/kiwixmobile/utils/files/FileSearch.java

@@ -1,296 +0,0 @@
-/*
- * Copyright 2013 Rashiq Ahmad <rashiq.z@gmail.com>
- *
- * 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
- * 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, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
- * MA 02110-1301, USA.
- */
-
-package org.kiwix.kiwixmobile.utils.files;
-
-import android.content.ContentResolver;
-import android.content.Context;
-import android.database.Cursor;
-import android.net.Uri;
-import android.os.Environment;
-import android.provider.MediaStore;
-import android.util.Log;
-import eu.mhutti1.utils.storage.StorageDevice;
-import eu.mhutti1.utils.storage.StorageDeviceUtils;
-import java.io.File;
-import java.io.FilenameFilter;
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.List;
-import java.util.Vector;
-import org.kiwix.kiwixmobile.data.ZimContentProvider;
-import org.kiwix.kiwixmobile.downloader.model.DownloadModel;
-import org.kiwix.kiwixmobile.library.entity.LibraryNetworkEntity;
-import org.kiwix.kiwixmobile.utils.StorageUtils;
-import org.kiwix.kiwixmobile.zim_manager.fileselect_view.adapter.BooksOnDiskListItem;
-
-import static org.kiwix.kiwixmobile.utils.Constants.TAG_KIWIX;
-
-public class FileSearch {
-
-  // Array of zim file extensions
-  public static final String[] zimFiles = { "zim", "zimaa" };
-
-  private final Context context;
-  private final List<DownloadModel> downloads;
-  private final ResultListener listener;
-
-  private boolean fileSystemScanCompleted = false;
-  private boolean mediaStoreScanCompleted = false;
-
-  public FileSearch(Context ctx, List<DownloadModel> downloads, ResultListener listener) {
-    this.context = ctx;
-    this.downloads = downloads;
-    this.listener = listener;
-  }
-
-  public static synchronized LibraryNetworkEntity.Book fileToBook(String filePath) {
-    LibraryNetworkEntity.Book book = null;
-
-    if (ZimContentProvider.zimFileName != null) {
-      ZimContentProvider.originalFileName = ZimContentProvider.zimFileName;
-    }
-    // Check a file isn't being opened and temporally use content provider to access details
-    // This is not a great solution as we shouldn't need to fully open our ZIM files to get their metadata
-    if (ZimContentProvider.canIterate) {
-      if (ZimContentProvider.setZimFile(filePath) != null) {
-        try {
-          book = new LibraryNetworkEntity.Book();
-          book.title = ZimContentProvider.getZimFileTitle();
-          book.id = ZimContentProvider.getId();
-          book.file = new File(filePath);
-          book.size = String.valueOf(ZimContentProvider.getFileSize());
-          book.favicon = ZimContentProvider.getFavicon();
-          book.creator = ZimContentProvider.getCreator();
-          book.publisher = ZimContentProvider.getPublisher();
-          book.date = ZimContentProvider.getDate();
-          book.description = ZimContentProvider.getDescription();
-          book.language = ZimContentProvider.getLanguage();
-        } catch (Exception e) {
-          // TODO 20171215 Consider more elegant approaches.
-          // This is to see if we can catch the exception at all!
-          Log.e("kiwix-filesearch", "Problem parsing a book entry from the library file. ", e);
-          return null;
-        }
-      }
-    }
-    // Return content provider to its previous state
-    if (!ZimContentProvider.originalFileName.equals("")) {
-      ZimContentProvider.setZimFile(ZimContentProvider.originalFileName);
-    }
-    ZimContentProvider.originalFileName = "";
-
-    return book;
-  }
-
-  public void scan(String defaultPath) {
-    // Start custom file search
-    new Thread(() -> {
-      scanFileSystem(defaultPath);
-      fileSystemScanCompleted = true;
-      checkCompleted();
-    }).start();
-
-    // Star mediastore search
-    new Thread(() -> {
-      scanMediaStore();
-      mediaStoreScanCompleted = true;
-      checkCompleted();
-    }).start();
-  }
-
-  // If both searches are complete callback
-  private synchronized void checkCompleted() {
-    if (mediaStoreScanCompleted && fileSystemScanCompleted) {
-      listener.onScanCompleted();
-    }
-  }
-
-  public void scanMediaStore() {
-    ContentResolver contentResolver = context.getContentResolver();
-    Uri uri = MediaStore.Files.getContentUri("external");
-
-    String[] projection = { MediaStore.MediaColumns.DATA };
-    String selection =
-        MediaStore.MediaColumns.DATA + " like ? or " + MediaStore.MediaColumns.DATA + " like ? ";
-
-    Cursor query = contentResolver.query(uri, projection, selection,
-        new String[] { "%." + zimFiles[0], "%." + zimFiles[1] }, null);
-
-    if (query == null) {
-      return;
-    }
-
-    try {
-      while (query.moveToNext()) {
-        File file = new File(query.getString(0));
-        if (file.canRead()) {
-          onFileFound(file.getAbsolutePath());
-        }
-      }
-    } finally {
-      query.close();
-    }
-  }
-
-  // Scan through the file system and find all the files with .zim and .zimaa extensions
-  public void scanFileSystem(String defaultPath) {
-    FilenameFilter[] filter = new FilenameFilter[zimFiles.length];
-
-    // Search all external directories that we can find.
-    final ArrayList<StorageDevice> storageDevices =
-        StorageDeviceUtils.getStorageDevices(context, false);
-    String[] tempRoots = new String[storageDevices.size() + 2];
-    int j = 0;
-    tempRoots[j++] = "/mnt";
-    tempRoots[j++] = defaultPath;
-    for (StorageDevice storageDevice : storageDevices) {
-      tempRoots[j++] = storageDevice.getName();
-    }
-
-    int i = 0;
-    for (final String extension : zimFiles) {
-      filter[i] = (dir, name) -> name.endsWith("." + extension);
-      i++;
-    }
-
-    String dirNamePrimary = new File(
-        Environment.getExternalStorageDirectory().getAbsolutePath()).toString();
-
-    for (final String dirName : tempRoots) {
-      if (dirNamePrimary.equals(dirName)) {
-        // We already got this directory from getExternalStorageDirectory().
-        continue;
-      }
-      File f = new File(dirName);
-      if (f.isDirectory()) {
-        scanDirectory(dirName, filter);
-      } else {
-        Log.i(TAG_KIWIX, "Skipping missing directory " + dirName);
-      }
-    }
-  }
-
-  // Iterate through the file system
-  private Collection<File> listFiles(File directory, FilenameFilter[] filter, int recurse) {
-
-    Vector<File> files = new Vector<>();
-
-    File[] entries = directory.listFiles();
-
-    if (entries != null) {
-      for (File entry : entries) {
-        for (FilenameFilter filefilter : filter) {
-          if (filter == null || filefilter.accept(directory, entry.getName())) {
-            files.add(entry);
-          }
-        }
-        if ((recurse <= -1) || (recurse > 0 && entry.isDirectory())) {
-          recurse--;
-          files.addAll(listFiles(entry, filter, recurse));
-          recurse++;
-        }
-      }
-    }
-    return files;
-  }
-
-  private File[] listFilesAsArray(File directory, FilenameFilter[] filter, int recurse) {
-    Collection<File> files = listFiles(directory, filter, recurse);
-
-    File[] arr = new File[files.size()];
-    return files.toArray(arr);
-  }
-
-  public static synchronized BooksOnDiskListItem.BookOnDisk fileToBookOnDisk(String filePath) {
-    LibraryNetworkEntity.Book book = null;
-
-    if (ZimContentProvider.zimFileName != null) {
-      ZimContentProvider.originalFileName = ZimContentProvider.zimFileName;
-    }
-    // Check a file isn't being opened and temporally use content provider to access details
-    // This is not a great solution as we shouldn't need to fully open our ZIM files to get their metadata
-    if (ZimContentProvider.canIterate) {
-      if (ZimContentProvider.setZimFile(filePath) != null) {
-        try {
-          book = new LibraryNetworkEntity.Book();
-          book.title = ZimContentProvider.getZimFileTitle();
-          book.id = ZimContentProvider.getId();
-          book.size = String.valueOf(ZimContentProvider.getFileSize());
-          book.favicon = ZimContentProvider.getFavicon();
-          book.creator = ZimContentProvider.getCreator();
-          book.publisher = ZimContentProvider.getPublisher();
-          book.date = ZimContentProvider.getDate();
-          book.description = ZimContentProvider.getDescription();
-          book.language = ZimContentProvider.getLanguage();
-        } catch (Exception e) {
-          // TODO 20171215 Consider more elegant approaches.
-          // This is to see if we can catch the exception at all!
-          Log.e("kiwix-filesearch", "Problem parsing a book entry from the library file. ", e);
-          return null;
-        }
-      }
-    }
-    // Return content provider to its previous state
-    if (!ZimContentProvider.originalFileName.equals("")) {
-      ZimContentProvider.setZimFile(ZimContentProvider.originalFileName);
-    }
-    ZimContentProvider.originalFileName = "";
-
-    return book == null ? null
-        : new BooksOnDiskListItem.BookOnDisk(null, book, new File(filePath),0L);
-  }
-
-  // Fill fileList with files found in the specific directory
-  private void scanDirectory(String directory, FilenameFilter[] filter) {
-    Log.d(TAG_KIWIX, "Searching directory " + directory);
-    File[] foundFiles = listFilesAsArray(new File(directory), filter, -1);
-    for (File f : foundFiles) {
-      Log.d(TAG_KIWIX, "Found " + f.getAbsolutePath());
-      onFileFound(f.getAbsolutePath());
-    }
-  }
-
-  // Callback that a new file has been found
-  public void onFileFound(String filePath) {
-    if (fileIsDownloading(filePath)) {
-      return;
-    }
-    BooksOnDiskListItem.BookOnDisk book = fileToBookOnDisk(filePath);
-
-    if (book != null) {
-      listener.onBookFound(book);
-    }
-  }
-
-  private boolean fileIsDownloading(String filePath) {
-    for (DownloadModel download : downloads) {
-      if (filePath.endsWith(StorageUtils.getFileNameFromUrl(download.getBook().getUrl()))) {
-        return true;
-      }
-    }
-    return false;
-  }
-
-  public interface ResultListener {
-    void onBookFound(BooksOnDiskListItem.BookOnDisk book);
-
-    void onScanCompleted();
-  }
-}

app/src/main/java/org/kiwix/kiwixmobile/utils/files/FileSearch.kt

@@ -0,0 +1,86 @@
+/*
+ * Copyright 2013 Rashiq Ahmad <rashiq.z@gmail.com>
+ *
+ * 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
+ * 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301, USA.
+ */
+
+package org.kiwix.kiwixmobile.utils.files
+
+import android.content.Context
+import android.os.Environment
+import android.provider.MediaStore.Files
+import android.provider.MediaStore.MediaColumns
+import eu.mhutti1.utils.storage.StorageDeviceUtils
+import io.reactivex.Flowable
+import io.reactivex.functions.BiFunction
+import org.kiwix.kiwixmobile.extensions.forEachRow
+import org.kiwix.kiwixmobile.extensions.get
+import java.io.File
+import javax.inject.Inject
+
+class FileSearch @Inject constructor(private val context: Context) {
+
+  val zimFileExtensions = arrayOf("zim", "zimaa")
+
+  fun scan(defaultPath: String) =
+    Flowable.combineLatest(
+        Flowable.fromCallable { scanFileSystem(defaultPath) },
+        Flowable.fromCallable(this::scanMediaStore),
+        BiFunction<List<File>, List<File>, List<File>> { filesSystemFiles, mediaStoreFiles ->
+          filesSystemFiles + mediaStoreFiles
+        }
+    )
+
+  private fun scanMediaStore() = mutableListOf<File>().apply {
+    queryMediaStore()
+        ?.forEachRow { cursor ->
+          File(cursor.get<String>(MediaColumns.DATA)).takeIf(File::canRead)
+              ?.also { add(it) }
+        }
+  }
+
+  private fun queryMediaStore() = context.contentResolver
+      .query(
+          Files.getContentUri("external"),
+          arrayOf(MediaColumns.DATA),
+          MediaColumns.DATA + " like ? or " + MediaColumns.DATA + " like ? ",
+          arrayOf("%." + zimFileExtensions[0], "%." + zimFileExtensions[1]),
+          null
+      )
+
+  private fun scanFileSystem(defaultPath: String) =
+    directoryRoots(defaultPath)
+        .minus(Environment.getExternalStorageDirectory().absolutePath)
+        .fold(mutableListOf<File>(), { acc, root ->
+          acc.apply { addAll(scanDirectory(root)) }
+        })
+
+  private fun directoryRoots(defaultPath: String) = listOf(
+      "/mnt",
+      defaultPath,
+      *StorageDeviceUtils.getStorageDevices(context, false).map { it.name }.toTypedArray()
+  )
+
+  private fun scanDirectory(directory: String) = filesMatchingExtensions(directory) ?: emptyList()
+
+  private fun filesMatchingExtensions(directory: String) = File(directory)
+      .listFiles { _, name -> name.endsWithAny(*zimFileExtensions) }
+      ?.toList()
+
+}
+
+private fun String.endsWithAny(vararg suffixes: String) =
+  suffixes.fold(false, { acc, s -> acc or endsWith(s) })

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

@@ -52,9 +52,24 @@ import org.kiwix.kiwixmobile.zim_manager.Fat32Checker.FileSystemState.CanWrite4G
 import org.kiwix.kiwixmobile.zim_manager.Fat32Checker.FileSystemState.CannotWrite4GbFile
 import org.kiwix.kiwixmobile.zim_manager.Fat32Checker.FileSystemState.NotEnoughSpaceFor4GbFile
 import org.kiwix.kiwixmobile.zim_manager.NetworkState.CONNECTED
+import org.kiwix.kiwixmobile.zim_manager.ZimManageViewModel.FileSelectActions.MultiModeFinished
+import org.kiwix.kiwixmobile.zim_manager.ZimManageViewModel.FileSelectActions.RequestDeleteMultiSelection
+import org.kiwix.kiwixmobile.zim_manager.ZimManageViewModel.FileSelectActions.RequestMultiSelection
+import org.kiwix.kiwixmobile.zim_manager.ZimManageViewModel.FileSelectActions.RequestOpen
+import org.kiwix.kiwixmobile.zim_manager.ZimManageViewModel.FileSelectActions.RequestSelect
+import org.kiwix.kiwixmobile.zim_manager.ZimManageViewModel.FileSelectActions.RequestShareMultiSelection
+import org.kiwix.kiwixmobile.zim_manager.fileselect_view.FileSelectListState
+import org.kiwix.kiwixmobile.zim_manager.fileselect_view.SelectionMode.MULTI
+import org.kiwix.kiwixmobile.zim_manager.fileselect_view.SelectionMode.NORMAL
 import org.kiwix.kiwixmobile.zim_manager.fileselect_view.StorageObserver
 import org.kiwix.kiwixmobile.zim_manager.fileselect_view.adapter.BooksOnDiskListItem
 import org.kiwix.kiwixmobile.zim_manager.fileselect_view.adapter.BooksOnDiskListItem.BookOnDisk
+import org.kiwix.kiwixmobile.zim_manager.fileselect_view.effects.DeleteFiles
+import org.kiwix.kiwixmobile.zim_manager.fileselect_view.effects.None
+import org.kiwix.kiwixmobile.zim_manager.fileselect_view.effects.OpenFile
+import org.kiwix.kiwixmobile.zim_manager.fileselect_view.effects.ShareFiles
+import org.kiwix.kiwixmobile.zim_manager.fileselect_view.effects.SideEffect
+import org.kiwix.kiwixmobile.zim_manager.fileselect_view.effects.StartMultiSelection
 import org.kiwix.kiwixmobile.zim_manager.library_view.adapter.LibraryListItem
 import org.kiwix.kiwixmobile.zim_manager.library_view.adapter.LibraryListItem.BookItem
 import org.kiwix.kiwixmobile.zim_manager.library_view.adapter.LibraryListItem.DividerItem
@@ -79,16 +94,26 @@ class ZimManageViewModel @Inject constructor(
   private val defaultLanguageProvider: DefaultLanguageProvider,
   private val dataSource: DataSource
 ) : ViewModel() {
+  sealed class FileSelectActions {
+    data class RequestOpen(val bookOnDisk: BookOnDisk) : FileSelectActions()
+    data class RequestSelect(val bookOnDisk: BookOnDisk) : FileSelectActions()
+    data class RequestMultiSelection(val bookOnDisk: BookOnDisk) : FileSelectActions()
+    object RequestDeleteMultiSelection : FileSelectActions()
+    object RequestShareMultiSelection : FileSelectActions()
+    object MultiModeFinished : FileSelectActions()
+  }
 
+  val sideEffects = PublishProcessor.create<SideEffect<out Any?>>()
   val libraryItems: MutableLiveData<List<LibraryListItem>> = MutableLiveData()
   val downloadItems: MutableLiveData<List<DownloadItem>> = MutableLiveData()
-  val bookItems: MutableLiveData<List<BooksOnDiskListItem>> = MutableLiveData()
+  val fileSelectListStates: MutableLiveData<FileSelectListState> = MutableLiveData()
   val deviceListIsRefreshing = MutableLiveData<Boolean>()
   val libraryListIsRefreshing = MutableLiveData<Boolean>()
   val networkStates = MutableLiveData<NetworkState>()
   val languageItems = MutableLiveData<List<Language>>()
 
   val requestFileSystemCheck = PublishProcessor.create<Unit>()
+  val fileSelectActions = PublishProcessor.create<FileSelectActions>()
   val requestDownloadLibrary = BehaviorProcessor.createDefault<Unit>(Unit)
   val requestFiltering = BehaviorProcessor.createDefault<String>("")
   val requestLanguagesDialog = PublishProcessor.create<Unit>()
@@ -127,10 +152,74 @@ class ZimManageViewModel @Inject constructor(
         updateLanguagesInDao(networkLibrary, languages),
         updateNetworkStates(),
         updateLanguageItemsForDialog(languages),
-        requestsAndConnectivtyChangesToLibraryRequests(networkLibrary)
+        requestsAndConnectivtyChangesToLibraryRequests(networkLibrary),
+        fileSelectActions()
     )
   }
 
+  private fun fileSelectActions() = fileSelectActions.subscribe({
+    sideEffects.offer(
+        when (it) {
+          is RequestOpen -> OpenFile(it.bookOnDisk)
+          is RequestMultiSelection -> startMultiSelectionAndSelectBook(it.bookOnDisk)
+          RequestDeleteMultiSelection -> DeleteFiles(selectionsFromState())
+          RequestShareMultiSelection -> ShareFiles(selectionsFromState())
+          MultiModeFinished -> noSideEffectAndClearSelectionState()
+          is RequestSelect -> noSideEffectSelectBook(it.bookOnDisk)
+        }
+    )
+  }, Throwable::printStackTrace)
+
+  private fun startMultiSelectionAndSelectBook(
+    bookOnDisk: BookOnDisk
+  ): StartMultiSelection {
+    fileSelectListStates.value?.let {
+      fileSelectListStates.postValue(
+          it.copy(
+              bookOnDiskListItems = selectBook(it, bookOnDisk),
+              selectionMode = MULTI
+          )
+      )
+    }
+    return StartMultiSelection(bookOnDisk, fileSelectActions)
+  }
+
+  private fun selectBook(
+    it: FileSelectListState,
+    bookOnDisk: BookOnDisk
+  ): List<BooksOnDiskListItem> {
+    return it.bookOnDiskListItems.map { listItem ->
+      if (listItem.id == bookOnDisk.id) listItem.apply { isSelected = !isSelected }
+      else listItem
+    }
+  }
+
+  private fun noSideEffectSelectBook(bookOnDisk: BookOnDisk): SideEffect<Unit> {
+    fileSelectListStates.value?.let {
+      fileSelectListStates.postValue(
+          it.copy(bookOnDiskListItems = it.bookOnDiskListItems.map { listItem ->
+            if (listItem.id == bookOnDisk.id) listItem.apply { isSelected = !isSelected }
+            else listItem
+          })
+      )
+    }
+    return None
+  }
+
+  private fun selectionsFromState() = fileSelectListStates.value?.selectedBooks ?: emptyList()
+
+  private fun noSideEffectAndClearSelectionState(): SideEffect<Unit> {
+    fileSelectListStates.value?.let {
+      fileSelectListStates.postValue(
+          it.copy(
+              bookOnDiskListItems = it.bookOnDiskListItems.map { it.apply { isSelected = false } },
+              selectionMode = NORMAL
+          )
+      )
+    }
+    return None
+  }
+
   private fun requestsAndConnectivtyChangesToLibraryRequests(library: PublishProcessor<LibraryNetworkEntity>) =
     Flowable.combineLatest(
         requestDownloadLibrary,
@@ -411,10 +500,27 @@ class ZimManageViewModel @Inject constructor(
   private fun updateBookItems() =
     dataSource.booksOnDiskAsListItems()
         .subscribe(
-            bookItems::postValue,
+            { newList ->
+              fileSelectListStates.postValue(
+                  fileSelectListStates.value?.let { inheritSelections(it, newList) }
+                      ?: FileSelectListState(newList)
+              )
+            },
             Throwable::printStackTrace
         )
 
+  private fun inheritSelections(
+    oldState: FileSelectListState,
+    newList: MutableList<BooksOnDiskListItem>
+  ): FileSelectListState {
+    return oldState.copy(
+        bookOnDiskListItems = newList.map { newBookOnDisk ->
+          val firstOrNull =
+            oldState.bookOnDiskListItems.firstOrNull { oldBookOnDisk -> oldBookOnDisk.id == newBookOnDisk.id }
+          newBookOnDisk.apply { isSelected = firstOrNull?.isSelected ?: false }
+        })
+  }
+
   private fun removeCompletedDownloadsFromDb(downloadStatuses: Flowable<List<DownloadStatus>>) =
     downloadStatuses
         .observeOn(Schedulers.io())

app/src/main/java/org/kiwix/kiwixmobile/zim_manager/fileselect_view/FileSelectListState.kt

@@ -0,0 +1,37 @@
+/*
+ * Kiwix Android
+ * Copyright (C) 2018  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.zim_manager.fileselect_view
+
+import org.kiwix.kiwixmobile.zim_manager.fileselect_view.SelectionMode.NORMAL
+import org.kiwix.kiwixmobile.zim_manager.fileselect_view.adapter.BooksOnDiskListItem
+import org.kiwix.kiwixmobile.zim_manager.fileselect_view.adapter.BooksOnDiskListItem.BookOnDisk
+
+data class FileSelectListState(
+  val bookOnDiskListItems: List<BooksOnDiskListItem>,
+  val selectionMode: SelectionMode = NORMAL
+) {
+  val selectedBooks by lazy {
+    bookOnDiskListItems.filter { it.isSelected }.filterIsInstance(BookOnDisk::class.java)
+  }
+
+}
+
+enum class SelectionMode {
+  NORMAL,
+  MULTI
+}

app/src/main/java/org/kiwix/kiwixmobile/zim_manager/fileselect_view/StorageObserver.kt

@@ -1,45 +1,80 @@
 package org.kiwix.kiwixmobile.zim_manager.fileselect_view
 
-import android.content.Context
+import io.reactivex.functions.BiFunction
-import android.util.Log
-import io.reactivex.processors.PublishProcessor
 import io.reactivex.schedulers.Schedulers
+import org.kiwix.kiwixmobile.data.ZimContentProvider
 import org.kiwix.kiwixmobile.database.newdb.dao.NewDownloadDao
 import org.kiwix.kiwixmobile.downloader.model.DownloadModel
+import org.kiwix.kiwixmobile.library.entity.LibraryNetworkEntity.Book
 import org.kiwix.kiwixmobile.utils.SharedPreferenceUtil
 import org.kiwix.kiwixmobile.utils.files.FileSearch
-import org.kiwix.kiwixmobile.utils.files.FileSearch.ResultListener
 import org.kiwix.kiwixmobile.zim_manager.fileselect_view.adapter.BooksOnDiskListItem.BookOnDisk
+import java.io.File
 import javax.inject.Inject
 
 class StorageObserver @Inject constructor(
-  private val context: Context,
   private val sharedPreferenceUtil: SharedPreferenceUtil,
-  private val downloadDao: NewDownloadDao
+  downloadDao: NewDownloadDao,
+  private val fileSearch: FileSearch
 ) {
 
-  private val _booksOnFileSystem = PublishProcessor.create<List<BookOnDisk>>()
+  val booksOnFileSystem = scanFiles()
-  val booksOnFileSystem = _booksOnFileSystem.distinctUntilChanged()
+      .withLatestFrom(
-      .doOnSubscribe {
+          downloadDao.downloads(),
-        downloadDao.downloads()
+          BiFunction(this::toFilesThatAreNotDownloading)
-            .subscribeOn(Schedulers.io())
+      )
-            .take(1)
+      .map {
-            .subscribe(this::scanFiles, Throwable::printStackTrace)
+        it.mapNotNull { file -> convertToBookOnDisk(file) }
       }
 
-  private fun scanFiles(downloads: List<DownloadModel>) {
+  private fun toFilesThatAreNotDownloading(
-    FileSearch(context, downloads, object : ResultListener {
+    files: List<File>,
-      val foundBooks = mutableSetOf<BookOnDisk>()
+    downloads: List<DownloadModel>
+  ) = files.filter { fileHasNoMatchingDownload(downloads, it) }
 
-      override fun onBookFound(book: BookOnDisk) {
+  private fun fileHasNoMatchingDownload(
-        foundBooks.add(book)
+    downloads: List<DownloadModel>,
-        Log.i("Scanner", "File Search: Found Book " + book.book.title)
+    file: File
-      }
+  ) = downloads.firstOrNull {
+    file.absolutePath.endsWith(it.fileNameFromUrl)
+  } == null
 
-      override fun onScanCompleted() {
+  private fun scanFiles() = fileSearch.scan(sharedPreferenceUtil.prefStorage)
-        _booksOnFileSystem.onNext(foundBooks.toList())
+      .subscribeOn(Schedulers.io())
 
-      }
+  private fun convertToBookOnDisk(file: File): BookOnDisk? {
-    }).scan(sharedPreferenceUtil.prefStorage)
+    configureZimContentProvider()
+    var bookOnDisk: BookOnDisk? = null
+    if (ZimContentProvider.canIterate && ZimContentProvider.setZimFile(file.absolutePath) != null) {
+      bookOnDisk = BookOnDisk(book = bookFromZimContentProvider(), file = file)
+    }
+    resetZimContentProvider()
+    return bookOnDisk
+  }
+
+  private fun bookFromZimContentProvider() = Book().apply {
+    title = ZimContentProvider.getZimFileTitle()
+    id = ZimContentProvider.getId()
+    size = ZimContentProvider.getFileSize()
+        .toString()
+    favicon = ZimContentProvider.getFavicon()
+    creator = ZimContentProvider.getCreator()
+    publisher = ZimContentProvider.getPublisher()
+    date = ZimContentProvider.getDate()
+    description = ZimContentProvider.getDescription()
+    language = ZimContentProvider.getLanguage()
+  }
+
+  private fun configureZimContentProvider() {
+    if (ZimContentProvider.zimFileName != null) {
+      ZimContentProvider.originalFileName = ZimContentProvider.zimFileName
+    }
+  }
+
+  private fun resetZimContentProvider() {
+    if (ZimContentProvider.originalFileName != "") {
+      ZimContentProvider.setZimFile(ZimContentProvider.originalFileName)
+    }
+    ZimContentProvider.originalFileName = ""
   }
 }

app/src/main/java/org/kiwix/kiwixmobile/zim_manager/fileselect_view/ZimFileSelectFragment.kt

@@ -21,8 +21,8 @@ package org.kiwix.kiwixmobile.zim_manager.fileselect_view
 
 import android.Manifest
 import android.content.pm.PackageManager
-import android.os.Build
 import android.os.Bundle
+import android.view.ActionMode
 import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
@@ -32,49 +32,49 @@ import androidx.lifecycle.ViewModelProvider
 import androidx.lifecycle.ViewModelProviders
 import androidx.recyclerview.widget.LinearLayoutManager
 import androidx.recyclerview.widget.RecyclerView
+import io.reactivex.disposables.CompositeDisposable
 import kotlinx.android.synthetic.main.zim_list.file_management_no_files
 import kotlinx.android.synthetic.main.zim_list.zim_swiperefresh
 import kotlinx.android.synthetic.main.zim_list.zimfilelist
 import org.kiwix.kiwixmobile.R
-import org.kiwix.kiwixmobile.R.string
 import org.kiwix.kiwixmobile.base.BaseFragment
-import org.kiwix.kiwixmobile.data.ZimContentProvider
-import org.kiwix.kiwixmobile.database.newdb.dao.NewBookDao
 import org.kiwix.kiwixmobile.di.components.ActivityComponent
 import org.kiwix.kiwixmobile.extensions.toast
-import org.kiwix.kiwixmobile.utils.BookUtils
 import org.kiwix.kiwixmobile.utils.Constants.REQUEST_STORAGE_PERMISSION
-import org.kiwix.kiwixmobile.utils.DialogShower
-import org.kiwix.kiwixmobile.utils.KiwixDialog.DeleteZim
 import org.kiwix.kiwixmobile.utils.LanguageUtils
 import org.kiwix.kiwixmobile.utils.SharedPreferenceUtil
-import org.kiwix.kiwixmobile.utils.files.FileUtils
-import org.kiwix.kiwixmobile.zim_manager.ZimManageActivity
 import org.kiwix.kiwixmobile.zim_manager.ZimManageViewModel
+import org.kiwix.kiwixmobile.zim_manager.ZimManageViewModel.FileSelectActions
+import org.kiwix.kiwixmobile.zim_manager.ZimManageViewModel.FileSelectActions.RequestMultiSelection
+import org.kiwix.kiwixmobile.zim_manager.ZimManageViewModel.FileSelectActions.RequestOpen
+import org.kiwix.kiwixmobile.zim_manager.ZimManageViewModel.FileSelectActions.RequestSelect
 import org.kiwix.kiwixmobile.zim_manager.fileselect_view.adapter.BookOnDiskDelegate.BookDelegate
 import org.kiwix.kiwixmobile.zim_manager.fileselect_view.adapter.BookOnDiskDelegate.LanguageDelegate
 import org.kiwix.kiwixmobile.zim_manager.fileselect_view.adapter.BooksOnDiskAdapter
-import org.kiwix.kiwixmobile.zim_manager.fileselect_view.adapter.BooksOnDiskListItem.BookOnDisk
 import javax.inject.Inject
 
 class ZimFileSelectFragment : BaseFragment() {
 
   @Inject lateinit var sharedPreferenceUtil: SharedPreferenceUtil
-  @Inject lateinit var bookDao: NewBookDao
-  @Inject lateinit var dialogShower: DialogShower
   @Inject lateinit var viewModelFactory: ViewModelProvider.Factory
-  @Inject lateinit var bookUtils: BookUtils
+
+  private var actionMode: ActionMode? = null
+  val disposable = CompositeDisposable()
 
   private val zimManageViewModel: ZimManageViewModel by lazy {
     ViewModelProviders.of(activity!!, viewModelFactory)
         .get(ZimManageViewModel::class.java)
   }
 
+  private val bookDelegate: BookDelegate by lazy {
+    BookDelegate(sharedPreferenceUtil,
+        { offerAction(RequestOpen(it)) },
+        { offerAction(RequestMultiSelection(it)) },
+        { offerAction(RequestSelect(it)) })
+  }
+
   private val booksOnDiskAdapter: BooksOnDiskAdapter by lazy {
-    BooksOnDiskAdapter(
+    BooksOnDiskAdapter(bookDelegate, LanguageDelegate)
-        BookDelegate(sharedPreferenceUtil, this::openOnClick, this::deleteOnLongClick),
-        LanguageDelegate
-    )
   }
 
   override fun inject(activityComponent: ActivityComponent) {
@@ -101,31 +101,51 @@ class ZimFileSelectFragment : BaseFragment() {
       layoutManager = LinearLayoutManager(context, RecyclerView.VERTICAL, false)
       setHasFixedSize(true)
     }
-    zimManageViewModel.bookItems.observe(this, Observer {
+    zimManageViewModel.fileSelectListStates.observe(this, Observer { render(it) })
-      booksOnDiskAdapter.itemList = it!!
+    disposable.add(sideEffects())
-      checkEmpty(it)
-    })
     zimManageViewModel.deviceListIsRefreshing.observe(this, Observer {
       zim_swiperefresh.isRefreshing = it!!
     })
   }
 
+  private fun sideEffects() = zimManageViewModel.sideEffects.subscribe(
+      {
+        val effectResult = it.invokeWith(activity!!)
+        if (effectResult is ActionMode) {
+          actionMode = effectResult
+        }
+      }, Throwable::printStackTrace
+  )
+
+  private fun render(state: FileSelectListState) {
+    val items = state.bookOnDiskListItems
+    bookDelegate.selectionMode = state.selectionMode
+    booksOnDiskAdapter.items = items
+    actionMode?.title = String.format("%d", state.selectedBooks.size)
+    file_management_no_files.visibility = if (items.isEmpty()) View.VISIBLE else View.GONE
+  }
+
   override fun onResume() {
     super.onResume()
     checkPermissions()
   }
 
-  private fun checkEmpty(books: List<Any>) {
+  override fun onDestroy() {
-    file_management_no_files.visibility =
+    super.onDestroy()
-      if (books.isEmpty()) View.VISIBLE
+    disposable.clear()
-      else View.GONE
+  }
+
+  private fun offerAction(
+    action: FileSelectActions
+  ) {
+    zimManageViewModel.fileSelectActions.offer(action)
   }
 
   private fun checkPermissions() {
     if (ContextCompat.checkSelfPermission(
             activity!!,
             Manifest.permission.WRITE_EXTERNAL_STORAGE
-        ) != PackageManager.PERMISSION_GRANTED && Build.VERSION.SDK_INT > 18
+        ) != PackageManager.PERMISSION_GRANTED
     ) {
       context.toast(R.string.request_storage)
       requestPermissions(
@@ -140,34 +160,4 @@ class ZimFileSelectFragment : BaseFragment() {
   private fun requestFileSystemCheck() {
     zimManageViewModel.requestFileSystemCheck.onNext(Unit)
   }
-
-  private fun openOnClick(it: BookOnDisk) {
-    val file = it.file
-    ZimContentProvider.canIterate = false
-    if (!file.canRead()) {
-      context.toast(string.error_filenotfound)
-    } else {
-      (activity as ZimManageActivity).finishResult(file.path)
-    }
-  }
-
-  private fun deleteOnLongClick(it: BookOnDisk) {
-    dialogShower.show(DeleteZim, {
-      if (deleteSpecificZimFile(it)) {
-        context.toast(string.delete_specific_zim_toast)
-      } else {
-        context.toast(string.delete_zim_failed)
-      }
-    })
-  }
-
-  private fun deleteSpecificZimFile(book: BookOnDisk): Boolean {
-    val file = book.file
-    FileUtils.deleteZimFile(file.path)
-    if (file.exists()) {
-      return false
-    }
-    bookDao.delete(book.databaseId!!)
-    return true
-  }
 }

app/src/main/java/org/kiwix/kiwixmobile/zim_manager/fileselect_view/adapter/BookOnDiskDelegate.kt

@@ -18,11 +18,13 @@
 package org.kiwix.kiwixmobile.zim_manager.fileselect_view.adapter
 
 import android.view.ViewGroup
+import androidx.recyclerview.widget.RecyclerView.ViewHolder
 import org.kiwix.kiwixmobile.R
 import org.kiwix.kiwixmobile.extensions.inflate
 import org.kiwix.kiwixmobile.utils.SharedPreferenceUtil
+import org.kiwix.kiwixmobile.zim_manager.fileselect_view.SelectionMode
+import org.kiwix.kiwixmobile.zim_manager.fileselect_view.SelectionMode.NORMAL
 import org.kiwix.kiwixmobile.zim_manager.fileselect_view.adapter.BookOnDiskViewHolder.BookViewHolder
-import org.kiwix.kiwixmobile.zim_manager.fileselect_view.adapter.BookOnDiskViewHolder.LanguageItemViewHolder
 import org.kiwix.kiwixmobile.zim_manager.fileselect_view.adapter.BooksOnDiskListItem.BookOnDisk
 import org.kiwix.kiwixmobile.zim_manager.fileselect_view.adapter.BooksOnDiskListItem.LanguageItem
 import org.kiwix.kiwixmobile.zim_manager.library_view.adapter.base.AbsDelegateAdapter
@@ -33,17 +35,28 @@ sealed class BookOnDiskDelegate<I : BooksOnDiskListItem, VH : BookOnDiskViewHold
   class BookDelegate(
     val sharedPreferenceUtil: SharedPreferenceUtil,
     val clickAction: (BookOnDisk) -> Unit,
-    val longClickAction: ((BookOnDisk) -> Unit)? = null
+    val longClickAction: ((BookOnDisk) -> Unit)? = null,
+    val multiSelectAction: ((BookOnDisk) -> Unit)? = null
   ) : BookOnDiskDelegate<BookOnDisk, BookViewHolder>() {
 
     override val itemClass = BookOnDisk::class.java
 
+    var selectionMode: SelectionMode = NORMAL
+
+    override fun bind(
+      viewHolder: ViewHolder,
+      itemToBind: BooksOnDiskListItem
+    ) {
+      (viewHolder as BookOnDiskViewHolder.BookViewHolder).bind((itemToBind as BookOnDisk), selectionMode)
+    }
+
     override fun createViewHolder(parent: ViewGroup) =
       BookViewHolder(
           parent.inflate(R.layout.item_book, false),
           sharedPreferenceUtil,
           clickAction,
-          longClickAction
+          longClickAction,
+          multiSelectAction
       )
   }
 

app/src/main/java/org/kiwix/kiwixmobile/zim_manager/fileselect_view/adapter/BooksOnDiskAdapter.kt

@@ -1,7 +1,6 @@
 package org.kiwix.kiwixmobile.zim_manager.fileselect_view.adapter
 
 import org.kiwix.kiwixmobile.zim_manager.library_view.adapter.base.AdapterDelegate
-import org.kiwix.kiwixmobile.zim_manager.library_view.adapter.base.AdapterDelegateManager
 import org.kiwix.kiwixmobile.zim_manager.library_view.adapter.base.BaseDelegateAdapter
 
 class BooksOnDiskAdapter(

app/src/main/java/org/kiwix/kiwixmobile/zim_manager/fileselect_view/adapter/BooksOnDiskListItem.kt

@@ -6,6 +6,7 @@ import java.io.File
 import java.util.Locale
 
 sealed class BooksOnDiskListItem {
+  var isSelected: Boolean = false
   abstract val id: Long
 
   data class LanguageItem constructor(

app/src/main/java/org/kiwix/kiwixmobile/zim_manager/fileselect_view/adapter/BooksOnDiskViewHolder.kt

@@ -3,6 +3,7 @@ package org.kiwix.kiwixmobile.zim_manager.fileselect_view.adapter
 import android.graphics.ColorMatrixColorFilter
 import android.view.View
 import kotlinx.android.synthetic.main.header_language.header_language
+import kotlinx.android.synthetic.main.item_book.itemBookCheckbox
 import kotlinx.android.synthetic.main.item_book.item_book_article_count
 import kotlinx.android.synthetic.main.item_book.item_book_date
 import kotlinx.android.synthetic.main.item_book.item_book_description
@@ -17,6 +18,9 @@ import org.kiwix.kiwixmobile.main.KiwixWebView
 import org.kiwix.kiwixmobile.utils.SharedPreferenceUtil
 import org.kiwix.kiwixmobile.zim_manager.KiloByte
 import org.kiwix.kiwixmobile.zim_manager.fileselect_view.ArticleCount
+import org.kiwix.kiwixmobile.zim_manager.fileselect_view.SelectionMode
+import org.kiwix.kiwixmobile.zim_manager.fileselect_view.SelectionMode.MULTI
+import org.kiwix.kiwixmobile.zim_manager.fileselect_view.SelectionMode.NORMAL
 import org.kiwix.kiwixmobile.zim_manager.fileselect_view.adapter.BooksOnDiskListItem.BookOnDisk
 import org.kiwix.kiwixmobile.zim_manager.fileselect_view.adapter.BooksOnDiskListItem.LanguageItem
 import org.kiwix.kiwixmobile.zim_manager.library_view.adapter.base.BaseViewHolder
@@ -28,10 +32,17 @@ sealed class BookOnDiskViewHolder<T : BooksOnDiskListItem>(containerView: View)
     containerView: View,
     private val sharedPreferenceUtil: SharedPreferenceUtil,
     private val clickAction: (BookOnDisk) -> Unit,
-    private val longClickAction: ((BookOnDisk) -> Unit)?
+    private val longClickAction: ((BookOnDisk) -> Unit)?,
+    private val multiSelectAction: ((BookOnDisk) -> Unit)?
   ) : BookOnDiskViewHolder<BookOnDisk>(containerView) {
 
     override fun bind(item: BookOnDisk) {
+    }
+
+    fun bind(
+      item: BookOnDisk,
+      selectionMode: SelectionMode
+    ) {
       val book = item.book
       item_book_title.text = book.getTitle()
       item_book_date.text = book.getDate()
@@ -59,24 +70,30 @@ sealed class BookOnDiskViewHolder<T : BooksOnDiskListItem>(containerView: View)
         item_book_label_video.visibility = View.GONE
       }
 
-      containerView.setOnClickListener {
+      itemBookCheckbox.isChecked = item.isSelected
-        clickAction.invoke(item)
+      when (selectionMode) {
-      }
+        MULTI -> {
-      containerView.setOnLongClickListener {
+          itemBookCheckbox.visibility = View.VISIBLE
-        longClickAction?.invoke(item)
+          containerView.setOnClickListener { multiSelectAction?.invoke(item) }
-        return@setOnLongClickListener true
+          containerView.setOnLongClickListener(null)
+        }
+        NORMAL -> {
+          itemBookCheckbox.visibility = View.GONE
+          containerView.setOnClickListener { clickAction.invoke(item) }
+          containerView.setOnLongClickListener {
+            longClickAction?.invoke(item)
+            return@setOnLongClickListener true
+          }
+        }
       }
     }
   }
-
-  class LanguageItemViewHolder(containerView: View) :
-      BookOnDiskViewHolder<LanguageItem>(containerView) {
-
-    override fun bind(item: LanguageItem) {
-      header_language.text = item.text
-    }
-  }
-
 }
 
+class LanguageItemViewHolder(containerView: View) :
+    BookOnDiskViewHolder<LanguageItem>(containerView) {
 
+  override fun bind(item: LanguageItem) {
+    header_language.text = item.text
+  }
+}

app/src/main/java/org/kiwix/kiwixmobile/zim_manager/fileselect_view/effects/DeleteFiles.kt

@@ -0,0 +1,42 @@
+package org.kiwix.kiwixmobile.zim_manager.fileselect_view.effects
+
+import android.app.Activity
+import org.kiwix.kiwixmobile.R.string
+import org.kiwix.kiwixmobile.database.newdb.dao.NewBookDao
+import org.kiwix.kiwixmobile.extensions.toast
+import org.kiwix.kiwixmobile.utils.DialogShower
+import org.kiwix.kiwixmobile.utils.KiwixDialog.DeleteZim
+import org.kiwix.kiwixmobile.utils.files.FileUtils
+import org.kiwix.kiwixmobile.zim_manager.fileselect_view.adapter.BooksOnDiskListItem.BookOnDisk
+import javax.inject.Inject
+
+class DeleteFiles(val booksOnDiskListItem: List<BookOnDisk>) :
+    SideEffect<Unit> {
+
+  @Inject lateinit var dialogShower: DialogShower
+  @Inject lateinit var newBookDao: NewBookDao
+
+  override fun invokeWith(activity: Activity) {
+    activityComponent(activity).inject(this)
+    booksOnDiskListItem.forEach {
+      dialogShower.show(DeleteZim, {
+        if (deleteSpecificZimFile(it)) {
+          activity.toast(string.delete_specific_zim_toast)
+        } else {
+          activity.toast(string.delete_zim_failed)
+        }
+      })
+    }
+  }
+
+  private fun deleteSpecificZimFile(book: BookOnDisk): Boolean {
+    val file = book.file
+    FileUtils.deleteZimFile(file.path)
+    if (file.exists()) {
+      return false
+    }
+    newBookDao.delete(book.databaseId!!)
+    return true
+  }
+
+}

app/src/main/java/org/kiwix/kiwixmobile/zim_manager/fileselect_view/effects/None.kt

@@ -0,0 +1,8 @@
+package org.kiwix.kiwixmobile.zim_manager.fileselect_view.effects
+
+import android.app.Activity
+
+object None : SideEffect<Unit> {
+  override fun invokeWith(activity: Activity) {
+  }
+}

app/src/main/java/org/kiwix/kiwixmobile/zim_manager/fileselect_view/effects/OpenFile.kt

@@ -0,0 +1,38 @@
+/*
+ * Kiwix Android
+ * Copyright (C) 2018  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.zim_manager.fileselect_view.effects
+
+import android.app.Activity
+import org.kiwix.kiwixmobile.R
+import org.kiwix.kiwixmobile.data.ZimContentProvider
+import org.kiwix.kiwixmobile.extensions.toast
+import org.kiwix.kiwixmobile.zim_manager.ZimManageActivity
+import org.kiwix.kiwixmobile.zim_manager.fileselect_view.adapter.BooksOnDiskListItem.BookOnDisk
+
+class OpenFile(val bookOnDisk: BookOnDisk): SideEffect<Unit> {
+
+  override fun invokeWith(activity: Activity) {
+    val file = bookOnDisk.file
+    ZimContentProvider.canIterate = false
+    if (!file.canRead()) {
+      activity.toast(R.string.error_filenotfound)
+    } else {
+      (activity as ZimManageActivity).finishResult(file.path)
+    }
+  }
+}

app/src/main/java/org/kiwix/kiwixmobile/zim_manager/fileselect_view/effects/ShareFiles.kt

@@ -0,0 +1,42 @@
+package org.kiwix.kiwixmobile.zim_manager.fileselect_view.effects
+
+import android.app.Activity
+import android.content.Intent
+import android.net.Uri
+import android.os.Build
+import androidx.core.content.FileProvider
+import org.kiwix.kiwixmobile.BuildConfig
+import org.kiwix.kiwixmobile.R
+import org.kiwix.kiwixmobile.zim_manager.fileselect_view.adapter.BooksOnDiskListItem.BookOnDisk
+
+class ShareFiles(val selectedBooks: List<BookOnDisk>) : SideEffect<Unit> {
+  override fun invokeWith(activity: Activity) {
+    val selectedFileShareIntent = Intent()
+    selectedFileShareIntent.action = Intent.ACTION_SEND_MULTIPLE
+    selectedFileShareIntent.type = "application/octet-stream"
+    val selectedFileContentURIs = selectedBooks.mapNotNull {
+      if (Build.VERSION.SDK_INT >= 24) {
+        FileProvider.getUriForFile(
+            activity,
+            BuildConfig.APPLICATION_ID + ".fileprovider",
+            it.file
+        )
+      } else {
+        Uri.fromFile(it.file)
+      }
+    }
+    selectedFileShareIntent.putParcelableArrayListExtra(
+        Intent.EXTRA_STREAM,
+        ArrayList(selectedFileContentURIs)
+    )
+    selectedFileShareIntent.flags = Intent.FLAG_GRANT_READ_URI_PERMISSION
+    val shareChooserIntent = Intent.createChooser(
+        selectedFileShareIntent,
+        activity.getString(R.string.selected_file_cab_app_chooser_title)
+    )
+    if (shareChooserIntent.resolveActivity(activity.getPackageManager()) != null) {
+      activity.startActivity(shareChooserIntent)  // Open the app chooser dialog
+    }
+  }
+
+}

app/src/main/java/org/kiwix/kiwixmobile/zim_manager/fileselect_view/effects/SideEffect.kt

@@ -0,0 +1,28 @@
+/*
+ * Kiwix Android
+ * Copyright (C) 2018  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.zim_manager.fileselect_view.effects
+
+import android.app.Activity
+import org.kiwix.kiwixmobile.KiwixApplication
+
+interface SideEffect<T:Any?> {
+  fun invokeWith(activity: Activity):T
+  fun activityComponent(activity: Activity) =
+    KiwixApplication.getApplicationComponent().activityComponent().activity(activity).build()
+}
+

app/src/main/java/org/kiwix/kiwixmobile/zim_manager/fileselect_view/effects/StartMultiSelection.kt

@@ -0,0 +1,27 @@
+package org.kiwix.kiwixmobile.zim_manager.fileselect_view.effects
+
+import android.app.Activity
+import android.view.ActionMode
+import io.reactivex.processors.PublishProcessor
+import org.kiwix.kiwixmobile.R
+import org.kiwix.kiwixmobile.extensions.startActionMode
+import org.kiwix.kiwixmobile.zim_manager.ZimManageViewModel.FileSelectActions
+import org.kiwix.kiwixmobile.zim_manager.ZimManageViewModel.FileSelectActions.RequestDeleteMultiSelection
+import org.kiwix.kiwixmobile.zim_manager.ZimManageViewModel.FileSelectActions.RequestShareMultiSelection
+import org.kiwix.kiwixmobile.zim_manager.fileselect_view.adapter.BooksOnDiskListItem
+
+data class StartMultiSelection(
+  val bookOnDisk: BooksOnDiskListItem.BookOnDisk,
+  val fileSelectActions: PublishProcessor<FileSelectActions>
+) : SideEffect<ActionMode?> {
+  override fun invokeWith(activity: Activity) =
+    activity.startActionMode(
+        R.menu.menu_zim_files_contextual,
+        mapOf(
+            R.id.zim_file_delete_item to { fileSelectActions.offer(RequestDeleteMultiSelection) },
+            R.id.zim_file_share_item to { fileSelectActions.offer(RequestShareMultiSelection) }
+        ),
+        { fileSelectActions.offer(FileSelectActions.MultiModeFinished) }
+    )
+
+}

app/src/main/java/org/kiwix/kiwixmobile/zim_manager/library_view/LibraryFragment.kt

@@ -140,7 +140,7 @@ class LibraryFragment : BaseFragment() {
   }
 
   private fun onLibraryItemsChange(it: List<LibraryListItem>?) {
-    libraryAdapter.itemList = it!!
+    libraryAdapter.items = it!!
     if (it.isEmpty()) {
       libraryErrorText.setText(
           if (isNotConnected) R.string.no_network_connection

app/src/main/java/org/kiwix/kiwixmobile/zim_manager/library_view/adapter/base/BaseDelegateAdapter.kt

@@ -30,7 +30,7 @@ abstract class BaseDelegateAdapter<ITEM>(
     setHasStableIds(true)
   }
 
-  var itemList: List<ITEM> = mutableListOf()
+  var items: List<ITEM> = mutableListOf()
     set(value) {
       field = value
       notifyDataSetChanged()
@@ -41,19 +41,19 @@ abstract class BaseDelegateAdapter<ITEM>(
     viewType: Int
   ) = delegateManager.createViewHolder(parent, viewType)
 
-  override fun getItemCount() = itemList.size
+  override fun getItemCount() = items.size
   override fun onBindViewHolder(
     holder: ViewHolder,
     position: Int
   ) {
-    delegateManager.onBindViewHolder(itemList[position], holder)
+    delegateManager.onBindViewHolder(items[position], holder)
   }
 
   override fun getItemViewType(position: Int) =
-    delegateManager.getViewTypeFor(itemList[position])
+    delegateManager.getViewTypeFor(items[position])
 
   override fun getItemId(position: Int): Long {
-    return getIdFor(itemList[position])
+    return getIdFor(items[position])
   }
 
   abstract fun getIdFor(item:ITEM):Long

app/src/main/res/layout/item_book.xml

@@ -4,7 +4,7 @@
     xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
-    android:background="?attr/selectableItemBackground"
+    android:background="?android:attr/selectableItemBackground"
     android:paddingEnd="0dp"
     android:paddingLeft="0dp"
     android:paddingRight="0dp"
@@ -12,13 +12,25 @@
     android:paddingTop="@dimen/activity_vertical_margin"
     >
 
+  <CheckBox
+      android:id="@+id/itemBookCheckbox"
+      android:layout_width="wrap_content"
+      android:layout_height="wrap_content"
+      android:visibility="gone"
+      android:paddingRight="10dp"
+      android:paddingEnd="10dp"
+      app:layout_constraintBottom_toBottomOf="parent"
+      app:layout_constraintStart_toStartOf="parent"
+      app:layout_constraintTop_toTopOf="parent"
+      />
+
   <ImageView
       android:id="@+id/item_book_icon"
       android:layout_width="40dp"
       android:layout_height="40dp"
       android:contentDescription="@string/favicon"
       app:layout_constraintBottom_toBottomOf="parent"
-      app:layout_constraintStart_toStartOf="parent"
+      app:layout_constraintStart_toEndOf="@id/itemBookCheckbox"
       app:layout_constraintTop_toTopOf="parent"
       tools:src="@mipmap/kiwix_icon_round"
       />

app/src/main/res/values-in

@@ -1 +0,0 @@
-values-id

app/src/main/res/values-iw

@@ -1 +0,0 @@
-values-he

app/src/main/res/values-ji

@@ -1 +0,0 @@
-values-yi

app/src/test/java/org/kiwix/kiwixmobile/TestModelFunctions.kt

@@ -27,11 +27,31 @@ import java.io.File
 
 fun bookOnDisk(
   book: Book = book(),
-  databaseId: Long = 0L,
+  databaseId: Long? = 0L,
   file: File = File("")
 ) = BookOnDisk(databaseId, book, file)
 
-fun book(id: String = "0") = Book().apply { this.id = id }
+fun book(
+  id: String = "0",
+  title: String = "",
+  size: String = "",
+  favicon: String = "",
+  creator: String = "",
+  publisher: String = "",
+  date: String = "",
+  description: String = "",
+  language: String = ""
+) = Book().apply {
+  this.id = id
+  this.title = title
+  this.size = size
+  this.favicon = favicon
+  this.creator = creator
+  this.publisher = publisher
+  this.date = date
+  this.description = description
+  this.language = language
+}
 
 fun downloadStatus(
   downloadId: Long = 0L,

app/src/test/java/org/kiwix/kiwixmobile/TestUtilitiyFunctions.kt

@@ -0,0 +1,34 @@
+/*
+ * Kiwix Android
+ * Copyright (C) 2018  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
+
+import io.reactivex.Scheduler
+import io.reactivex.android.plugins.RxAndroidPlugins
+import io.reactivex.plugins.RxJavaPlugins
+
+fun setScheduler(replacementScheduler: Scheduler) {
+  RxJavaPlugins.setIoSchedulerHandler { scheduler -> replacementScheduler }
+  RxJavaPlugins.setComputationSchedulerHandler { scheduler -> replacementScheduler }
+  RxJavaPlugins.setNewThreadSchedulerHandler { scheduler -> replacementScheduler }
+  RxAndroidPlugins.setInitMainThreadSchedulerHandler { scheduler -> replacementScheduler }
+}
+
+fun resetSchedulers() {
+  RxJavaPlugins.reset()
+  RxAndroidPlugins.reset()
+}

app/src/test/java/org/kiwix/kiwixmobile/utils/files/FileSearchTest.kt

@@ -0,0 +1,139 @@
+/*
+ * Kiwix Android
+ * Copyright (C) 2018  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.utils.files
+
+import android.content.ContentResolver
+import android.content.Context
+import android.database.Cursor
+import android.os.Environment
+import android.provider.MediaStore.MediaColumns
+import eu.mhutti1.utils.storage.StorageDevice
+import eu.mhutti1.utils.storage.StorageDeviceUtils
+import io.mockk.clearMocks
+import io.mockk.every
+import io.mockk.mockk
+import io.mockk.mockkStatic
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.AfterAll
+import org.junit.jupiter.api.BeforeEach
+import org.junit.jupiter.api.Nested
+import org.junit.jupiter.api.Test
+import java.io.File
+
+class FileSearchTest {
+
+  private val context: Context = mockk()
+  private lateinit var fileSearch: FileSearch
+
+  private val externalStorageDirectory: File = mockk()
+  private val contentResolver: ContentResolver = mockk()
+  private val storageDevice: StorageDevice = mockk()
+
+  private val unitTestTempDirectoryPath = "unittest${File.separator}"
+
+  @BeforeEach
+  fun init() {
+    clearMocks(context, externalStorageDirectory, contentResolver, storageDevice)
+    deleteTempDirectory()
+    mockkStatic(StorageDeviceUtils::class)
+    mockkStatic(Environment::class)
+    every { Environment.getExternalStorageDirectory() } returns externalStorageDirectory
+    every { externalStorageDirectory.absolutePath } returns "/externalStorageDirectory"
+    every { context.contentResolver } returns contentResolver
+    every { StorageDeviceUtils.getStorageDevices(context, false) } returns arrayListOf(
+        storageDevice
+    )
+    every { storageDevice.name } returns "/deviceDir"
+    fileSearch = FileSearch(context)
+  }
+
+  @AfterAll
+  fun teardown() {
+    deleteTempDirectory()
+  }
+
+  @Nested
+  inner class FileSystem {
+
+    @Test
+    fun `scan of directory that doesn't exist returns nothing`() {
+      every { contentResolver.query(any(), any(), any(), any(), any()) } returns null
+      fileSearch.scan("doesNotExist")
+          .test()
+          .assertValue(listOf())
+    }
+
+    @Test
+    fun `scan of directory that has files returns files`() {
+      val zimFile = File.createTempFile("${unitTestTempDirectoryPath}fileToFind", ".zim")
+      val zimaaFile = File.createTempFile("${unitTestTempDirectoryPath}fileToFind2", ".zimaa")
+      File.createTempFile("${unitTestTempDirectoryPath}willNotFind", ".txt")
+      every { contentResolver.query(any(), any(), any(), any(), any()) } returns null
+      val fileList = fileSearch.scan(zimFile.parent)
+          .test()
+          .values()[0]
+      assertThat(fileList).containsExactlyInAnyOrder(zimFile, zimaaFile)
+    }
+  }
+
+  @Nested
+  inner class MediaStore {
+
+    @Test
+    fun `scan media store, if files are readable they are returned`() {
+      val fileToFind = File.createTempFile("${unitTestTempDirectoryPath}fileToFind", ".zim")
+      expectFromMediaStore(fileToFind)
+      fileSearch.scan("")
+          .test()
+          .assertValue(listOf(fileToFind))
+    }
+
+    @Test
+    fun `scan media store, if files are not readable they are not returned`() {
+      val unreadableFile = File.createTempFile("${unitTestTempDirectoryPath}fileToFind", ".zim")
+      expectFromMediaStore(unreadableFile)
+      unreadableFile.delete()
+      fileSearch.scan("")
+          .test()
+          .assertValue(listOf())
+    }
+
+    private fun expectFromMediaStore(fileToFind: File) {
+      val cursor = mockk<Cursor>()
+      every {
+        contentResolver.query(
+            null,
+            arrayOf(MediaColumns.DATA),
+            MediaColumns.DATA + " like ? or " + MediaColumns.DATA + " like ? ",
+            arrayOf("%." + "zim", "%." + "zimaa"),
+            null
+        )
+      } returns cursor
+      every { cursor.moveToNext() } returnsMany listOf(true, false)
+      every { cursor.columnNames } returns arrayOf(MediaColumns.DATA)
+      every { cursor.getColumnIndex(MediaColumns.DATA) } returns 0
+      every { cursor.getString(0) } returns fileToFind.absolutePath
+    }
+  }
+
+  private fun deleteTempDirectory() {
+    File.createTempFile("${unitTestTempDirectoryPath}temp", ".txt")
+        .parentFile.deleteRecursively()
+  }
+}

app/src/test/java/org/kiwix/kiwixmobile/zim_manager/ZimManageViewModelTest.kt

@@ -20,16 +20,12 @@ package org.kiwix.kiwixmobile.zim_manager
 
 import android.app.Application
 import com.jraska.livedata.test
-import io.mockk.clearMocks
+import io.mockk.clearAllMocks
 import io.mockk.every
 import io.mockk.mockk
 import io.mockk.verify
-import io.reactivex.Scheduler
 import io.reactivex.Single
-import io.reactivex.android.plugins.RxAndroidPlugins
-import io.reactivex.plugins.RxJavaPlugins
 import io.reactivex.processors.PublishProcessor
-import io.reactivex.schedulers.Schedulers
 import io.reactivex.schedulers.TestScheduler
 import org.junit.jupiter.api.AfterAll
 import org.junit.jupiter.api.BeforeEach
@@ -55,12 +51,15 @@ import org.kiwix.kiwixmobile.downloader.model.DownloadStatus
 import org.kiwix.kiwixmobile.downloader.model.UriToFileConverter
 import org.kiwix.kiwixmobile.library.entity.LibraryNetworkEntity
 import org.kiwix.kiwixmobile.library.entity.LibraryNetworkEntity.Book
+import org.kiwix.kiwixmobile.resetSchedulers
+import org.kiwix.kiwixmobile.setScheduler
 import org.kiwix.kiwixmobile.utils.BookUtils
 import org.kiwix.kiwixmobile.zim_manager.Fat32Checker.FileSystemState
 import org.kiwix.kiwixmobile.zim_manager.Fat32Checker.FileSystemState.CanWrite4GbFile
 import org.kiwix.kiwixmobile.zim_manager.Fat32Checker.FileSystemState.CannotWrite4GbFile
 import org.kiwix.kiwixmobile.zim_manager.NetworkState.CONNECTED
 import org.kiwix.kiwixmobile.zim_manager.NetworkState.NOT_CONNECTED
+import org.kiwix.kiwixmobile.zim_manager.fileselect_view.FileSelectListState
 import org.kiwix.kiwixmobile.zim_manager.fileselect_view.StorageObserver
 import org.kiwix.kiwixmobile.zim_manager.fileselect_view.adapter.BooksOnDiskListItem
 import org.kiwix.kiwixmobile.zim_manager.fileselect_view.adapter.BooksOnDiskListItem.BookOnDisk
@@ -104,26 +103,14 @@ class ZimManageViewModelTest {
     setScheduler(testScheduler)
   }
 
-  private fun setScheduler(replacementScheduler: Scheduler) {
-    RxJavaPlugins.setIoSchedulerHandler { scheduler -> replacementScheduler }
-    RxJavaPlugins.setComputationSchedulerHandler { scheduler -> replacementScheduler }
-    RxJavaPlugins.setNewThreadSchedulerHandler { scheduler -> replacementScheduler }
-    RxAndroidPlugins.setInitMainThreadSchedulerHandler { scheduler -> Schedulers.trampoline() }
-  }
-
   @AfterAll
   fun teardown() {
-    RxJavaPlugins.reset()
+    resetSchedulers()
-    RxAndroidPlugins.reset()
   }
 
   @BeforeEach
   fun init() {
-    clearMocks(
+    clearAllMocks()
-        newDownloadDao, newBookDao, newLanguagesDao, downloader,
-        storageObserver, kiwixService, application, connectivityBroadcastReceiver, bookUtils,
-        fat32Checker, uriToFileConverter, defaultLanguageProvider, dataSource
-    )
     every { connectivityBroadcastReceiver.action } returns "test"
     every { newDownloadDao.downloads() } returns downloads
     every { newBookDao.books() } returns books
@@ -235,8 +222,8 @@ class ZimManageViewModelTest {
       val expectedList = listOf(bookOnDisk())
       booksOnDiskListItems.onNext(expectedList)
       testScheduler.triggerActions()
-      viewModel.bookItems.test()
+      viewModel.fileSelectListStates.test()
-          .assertValue(expectedList)
+          .assertValue(FileSelectListState(expectedList))
     }
 
     @Test

app/src/test/java/org/kiwix/kiwixmobile/zim_manager/fileselect_view/StorageObserverTest.kt

@@ -0,0 +1,149 @@
+package org.kiwix.kiwixmobile.zim_manager.fileselect_view
+
+/*
+ * Kiwix Android
+ * Copyright (C) 2018  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/>.
+ */
+
+import io.mockk.clearAllMocks
+import io.mockk.every
+import io.mockk.mockk
+import io.mockk.mockkStatic
+import io.mockk.verify
+import io.reactivex.processors.PublishProcessor
+import io.reactivex.schedulers.Schedulers
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.AfterAll
+import org.junit.jupiter.api.BeforeEach
+import org.junit.jupiter.api.Test
+import org.kiwix.kiwixmobile.book
+import org.kiwix.kiwixmobile.bookOnDisk
+import org.kiwix.kiwixmobile.data.ZimContentProvider
+import org.kiwix.kiwixmobile.database.newdb.dao.NewDownloadDao
+import org.kiwix.kiwixmobile.downloader.model.DownloadModel
+import org.kiwix.kiwixmobile.library.entity.LibraryNetworkEntity.Book
+import org.kiwix.kiwixmobile.resetSchedulers
+import org.kiwix.kiwixmobile.setScheduler
+import org.kiwix.kiwixmobile.utils.SharedPreferenceUtil
+import org.kiwix.kiwixmobile.utils.files.FileSearch
+import java.io.File
+
+class StorageObserverTest {
+
+  private val sharedPreferenceUtil: SharedPreferenceUtil = mockk()
+  private val newDownloadDao: NewDownloadDao = mockk()
+  private val fileSearch: FileSearch = mockk()
+  private val downloadModel = mockk<DownloadModel>()
+  private val file = mockk<File>()
+
+  private val files: PublishProcessor<List<File>> = PublishProcessor.create()
+  private val downloads: PublishProcessor<List<DownloadModel>> = PublishProcessor.create()
+
+  private lateinit var storageObserver: StorageObserver
+
+  init {
+    setScheduler(Schedulers.trampoline())
+  }
+
+  @AfterAll
+  fun teardown() {
+    resetSchedulers()
+  }
+
+  @BeforeEach fun init() {
+    clearAllMocks()
+    every { sharedPreferenceUtil.prefStorage } returns "a"
+    every { fileSearch.scan("a") } returns files
+    every { newDownloadDao.downloads() } returns downloads
+    storageObserver = StorageObserver(sharedPreferenceUtil, newDownloadDao, fileSearch)
+  }
+
+  @Test
+  fun `books from disk are filtered by current downloads`() {
+    withFiltering()
+    booksOnFileSystem().assertValues(listOf())
+  }
+
+  @Test
+  fun `null books from ZimContentProvider are filtered out`() {
+    withNoFiltering()
+    booksOnFileSystem().assertValues(listOf())
+  }
+
+  @Test
+  fun `iterable ZimContentProvider with zim file produces a book`() {
+    val expectedBook = book(
+        "id", "title", "1", "favicon", "creator", "publisher", "date",
+        "description", "language"
+    )
+    mockkStatic(ZimContentProvider::class)
+    withNoFiltering()
+    every { ZimContentProvider.setZimFile("This won't match") } returns ""
+    expect(expectedBook)
+    booksOnFileSystem().assertValues(
+        listOf(
+            bookOnDisk(book = expectedBook, file = file, databaseId = null)
+        )
+    )
+    assertThat(ZimContentProvider.originalFileName).isEqualTo("")
+  }
+
+  @Test
+  fun `zim provider sets zim file to original file name if it exists`() {
+    withNoFiltering()
+    mockkStatic(ZimContentProvider::class)
+    every { ZimContentProvider.setZimFile(any()) } returns null
+    ZimContentProvider.zimFileName = "myZimFileName"
+    booksOnFileSystem().assertValues(listOf())
+    verify { ZimContentProvider.setZimFile("myZimFileName") }
+  }
+
+  @Test
+  fun `zim provider does not read book if it can not iterate`() {
+    withNoFiltering()
+    ZimContentProvider.canIterate = false
+    booksOnFileSystem().assertValues(listOf())
+  }
+
+  private fun booksOnFileSystem() = storageObserver.booksOnFileSystem
+      .test()
+      .also {
+        downloads.offer(listOf(downloadModel))
+        files.offer(listOf(file))
+      }
+
+  private fun expect(expectedBook: Book) {
+    every { ZimContentProvider.getZimFileTitle() } returns expectedBook.title
+    every { ZimContentProvider.getId() } returns expectedBook.id
+    every { ZimContentProvider.getFileSize() } returns expectedBook.size.toInt()
+    every { ZimContentProvider.getFavicon() } returns expectedBook.favicon
+    every { ZimContentProvider.getCreator() } returns expectedBook.creator
+    every { ZimContentProvider.getPublisher() } returns expectedBook.publisher
+    every { ZimContentProvider.getDate() } returns expectedBook.date
+    every { ZimContentProvider.getDescription() } returns expectedBook.description
+    every { ZimContentProvider.getLanguage() } returns expectedBook.language
+  }
+
+  private fun withFiltering() {
+    every { downloadModel.fileNameFromUrl } returns "test"
+    every { file.absolutePath } returns "This is a test"
+  }
+
+  private fun withNoFiltering() {
+    every { downloadModel.fileNameFromUrl } returns "test"
+    every { file.absolutePath } returns "This won't match"
+  }
+}

build.gradle.kts

@@ -35,7 +35,7 @@ ext {
   set("powerMockVersion", "1.6.6")
   set("powerMockJUnitVersion", "1.7.4")
   set("baristaVersion", "2.7.1")
-  set("kotlinVersion", "1.3.31")
+  set("kotlinVersion", "1.3.40")
   set("objectboxVersion", "2.3.4")
 }