Enhancement #779 : Add menu to share ZIM files (#866)

* Add issue#779.txt containing enhancement specifications

* UI Changes (Long click response - Contextual action bar)

* Fix Bug: List item selection bug, Add: Selected item highlighting

* Shift delete ZIM file functionality to CAB

* Add: Share ZIM file functionality to CAB (Cleanup to be done)

* Code clean up & comments

* Remove extra file

* Remove extra comment

* Update due to merge with master and pull request review

* Fix Bug: Share ZIM file on removable storage media (SD Card, USB Drive)

app/src/main/AndroidManifest.xml

@@ -186,7 +186,7 @@
 
     <provider
       android:name="android.support.v4.content.FileProvider"
-      android:authorities="${applicationId}.provider"
+      android:authorities="${applicationId}.fileprovider"
       android:exported="false"
       android:grantUriPermissions="true">
       <meta-data

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

@@ -17,21 +17,33 @@
  * MA 02110-1301, USA.
  */
 
+/**
+ * Fragment for list of downloaded ZIM files
+ */
+
 package org.kiwix.kiwixmobile.zim_manager.fileselect_view;
 
 import android.Manifest;
 import android.content.Context;
+import android.content.Intent;
 import android.content.pm.PackageManager;
+import android.net.Uri;
 import android.os.Build;
 import android.os.Bundle;
 import android.support.annotation.NonNull;
 import android.support.v4.content.ContextCompat;
+import android.support.v4.content.FileProvider;
 import android.support.v4.widget.SwipeRefreshLayout;
 import android.support.v7.app.AlertDialog;
 import android.util.Log;
+import android.view.ActionMode;
 import android.view.LayoutInflater;
+import android.view.Menu;
+import android.view.MenuInflater;
+import android.view.MenuItem;
 import android.view.View;
 import android.view.ViewGroup;
+import android.widget.AbsListView;
 import android.widget.AdapterView;
 import android.widget.AdapterView.OnItemClickListener;
 import android.widget.ArrayAdapter;
@@ -41,6 +53,7 @@ import android.widget.RelativeLayout;
 import android.widget.TextView;
 import android.widget.Toast;
 
+import org.kiwix.kiwixmobile.BuildConfig;
 import org.kiwix.kiwixmobile.KiwixApplication;
 import org.kiwix.kiwixmobile.R;
 import org.kiwix.kiwixmobile.base.BaseFragment;
@@ -113,7 +126,122 @@ public class ZimFileSelectFragment extends BaseFragment
 
     // Allow temporary use of ZimContentProvider to query books
     ZimContentProvider.canIterate = true;
-    return llLayout; // We must return the loaded Layout
+
+    // Setting up Contextual Action Mode in response to selection of ZIM files in the ListView
+    mZimFileList.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE_MODAL);
+    mZimFileList.setMultiChoiceModeListener(new AbsListView.MultiChoiceModeListener() {
+
+      // Holds positions corresponding to every selected list item in the ListView
+      private ArrayList<Integer> selectedViewPosition = new ArrayList<Integer>();
+
+      @Override
+      public void onItemCheckedStateChanged(ActionMode mode, int position, long id, boolean checked) {
+
+        if(checked) { // If the item was selected
+          selectedViewPosition.add(position);
+          mode.setTitle("" + selectedViewPosition.size()); // Update title of the CAB
+        }
+        else {  // If the item was deselected
+          selectedViewPosition.remove(Integer.valueOf(position));
+          mode.setTitle("" + selectedViewPosition.size()); // Update title of the CAB
+        }
+
+      }
+
+      @Override
+      public boolean onCreateActionMode(ActionMode mode, Menu menu) {
+        // Inflate and setup the Contextual Action Bar (CAB)
+        MenuInflater inflater = mode.getMenuInflater();
+        inflater.inflate(R.menu.menu_zim_files_contextual, menu);
+
+        return true;
+      }
+
+      @Override
+      public boolean onPrepareActionMode(ActionMode mode, Menu menu) {  // Leave the default implementation as is
+        return false;
+      }
+
+      @Override
+      public boolean onActionItemClicked(ActionMode mode, MenuItem item) {
+
+        switch(item.getItemId()) {  // Determine the action item clicked on in the CAB, and respond accordingly
+
+          // Initiate file deletion functionality for each selected list item (file)
+          case R.id.zim_file_delete_item :
+
+            for(int i = 0; i < selectedViewPosition.size(); i++)
+              deleteSpecificZimDialog(selectedViewPosition.get(i)); // Individually confirm & initiate deletion for each selected file
+
+            mode.finish(); // Action performed, so close CAB
+            return true;
+
+
+          // Initiate file sharing functionality for each selected list item (file)
+          case R.id.zim_file_share_item :
+
+            // Create an implicit intent for sharing multiple selected files
+            Intent selectedFileShareIntent = new Intent();
+            selectedFileShareIntent.setAction(Intent.ACTION_SEND_MULTIPLE);
+            selectedFileShareIntent.setType("application/octet-stream");  // ZIM files are binary data without an Android-predefined subtype
+
+            ArrayList<Uri> selectedFileContentURIs = new ArrayList<Uri>(); // Store Content URIs for all selected files being shared
+
+            for(int i = 0; i < selectedViewPosition.size(); i++) {
+
+              LibraryNetworkEntity.Book data = (LibraryNetworkEntity.Book) mZimFileList.getItemAtPosition(selectedViewPosition.get(i));
+              String shareFilePath = data.file.getPath(); //Returns path to file in device storage
+
+              /**
+               * Using 'file:///' URIs directly is unsafe as it grants the intent receiving application
+               * the same file system permissions as the intent creating app.
+               *
+               * FileProvider instead offers 'content://' URIs for sharing files, which offer temporary
+               * access permissions to the file being shared (to the intent receiving application), which
+               * is fundamentally safer.
+                */
+
+              File shareFile = new File(shareFilePath);
+              Uri shareContentUri = FileProvider.getUriForFile(getContext(), BuildConfig.APPLICATION_ID + ".fileprovider", shareFile);
+
+              if(shareContentUri != null)
+                selectedFileContentURIs.add(shareContentUri);  // Populate with the selected file content URIs
+            }
+
+            selectedFileShareIntent.putParcelableArrayListExtra(Intent.EXTRA_STREAM, selectedFileContentURIs); // Intent Extra for storing the array list of selected file content URIs
+
+            if(selectedFileContentURIs != null) {  // Grant temporary access permission to the intent receiver for the content URIs
+              selectedFileShareIntent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
+            }
+
+            /**
+             * Since a different app may be used for sharing everytime (E-mail, Cloud Upload, Wifi Sharing, etc.),
+             * so force an app chooser dialog every time some selected files are to be shared.
+              */
+            Intent shareChooserIntent = Intent.createChooser(selectedFileShareIntent, getResources().getString(R.string.selected_file_cab_app_chooser_title));
+
+            if(shareChooserIntent.resolveActivity(getActivity().getPackageManager()) != null)
+              startActivity(shareChooserIntent);  // Open the app chooser dialog
+
+            mode.finish(); // Action performed, so close CAB
+            return true;
+
+
+          default :
+            return false;
+
+        }
+      }
+
+      @Override
+      public void onDestroyActionMode(ActionMode mode) {
+        // Upon closure of the CAB, empty the array list of selected list item positions
+        selectedViewPosition.clear();
+      }
+
+    });
+
+    return llLayout; // Return the loaded Layout
   }
 
   @Override
@@ -129,8 +257,8 @@ public class ZimFileSelectFragment extends BaseFragment
     if (mZimFileList == null)
       return;
 
+    // Long click response is the Contextual Action Bar (Selected file deletion & sharing)
     mZimFileList.setOnItemClickListener(this);
-    mZimFileList.setOnItemLongClickListener(this);
     Collections.sort(books, new FileComparator());
     mFiles.clear();
     mFiles.addAll(books);
@@ -267,14 +395,14 @@ public class ZimFileSelectFragment extends BaseFragment
 
   @Override
   public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
-    deleteSpecificZimDialog(position);
-    return true;
+    return false;
   }
 
   public void deleteSpecificZimDialog(int position) {
     new AlertDialog.Builder(zimManageActivity, dialogStyle())
-        .setMessage(getString(R.string.delete_specific_zim))
+        .setMessage(mFiles.get(position).getTitle() + ": " + getString(R.string.delete_specific_zim))
         .setPositiveButton(getResources().getString(R.string.delete), (dialog, which) -> {
+          // Toast messages updated for coherence with the new manner of file deletion (from CAB)
           if (deleteSpecificZimFile(position)) {
             Toast.makeText(zimManageActivity, getResources().getString(R.string.delete_specific_zim_toast), Toast.LENGTH_SHORT).show();
           } else {

app/src/main/res/drawable/baseline_share_24.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="24dp"
+        android:height="24dp"
+        android:viewportWidth="24.0"
+        android:viewportHeight="24.0">
+    <path
+        android:fillColor="@android:color/white"
+        android:pathData="M18,16.08c-0.76,0 -1.44,0.3 -1.96,0.77L8.91,12.7c0.05,-0.23 0.09,-0.46 0.09,-0.7s-0.04,-0.47 -0.09,-0.7l7.05,-4.11c0.54,0.5 1.25,0.81 2.04,0.81 1.66,0 3,-1.34 3,-3s-1.34,-3 -3,-3 -3,1.34 -3,3c0,0.24 0.04,0.47 0.09,0.7L8.04,9.81C7.5,9.31 6.79,9 6,9c-1.66,0 -3,1.34 -3,3s1.34,3 3,3c0.79,0 1.5,-0.31 2.04,-0.81l7.12,4.16c-0.05,0.21 -0.08,0.43 -0.08,0.65 0,1.61 1.31,2.92 2.92,2.92 1.61,0 2.92,-1.31 2.92,-2.92s-1.31,-2.92 -2.92,-2.92z"/>
+</vector>

app/src/main/res/drawable/highlight.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<selector xmlns:android="http://schemas.android.com/apk/res/android">
+    <item
+        android:state_activated="true"
+        android:drawable="@color/greyed_out_selected"/>
+</selector>

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

@@ -8,7 +8,8 @@
   android:paddingBottom="@dimen/activity_vertical_margin"
   android:paddingLeft="@dimen/activity_horizontal_margin"
   android:paddingRight="@dimen/activity_horizontal_margin"
-  android:paddingTop="@dimen/activity_vertical_margin">
+  android:paddingTop="@dimen/activity_vertical_margin"
+  android:background="@drawable/highlight">
 
   <ImageView
     android:id="@+id/favicon"

app/src/main/res/menu/menu_zim_files_contextual.xml

@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="utf-8"?>
+<menu xmlns:android="http://schemas.android.com/apk/res/android"
+	xmlns:app="http://schemas.android.com/apk/res-auto">
+
+	<item
+		android:id="@+id/zim_file_delete_item"
+		android:icon="@drawable/ic_delete_white_24dp"
+		android:title="@string/delete"
+		android:visible="true"
+		app:iconifiedByDefault="true"
+		app:showAsAction="always" />
+
+	<item
+		android:id="@+id/zim_file_share_item"
+		android:icon="@drawable/baseline_share_24"
+		android:title="@string/share"
+		android:visible="true"
+		app:iconifiedByDefault="true"
+		app:showAsAction="always"/>
+
+</menu>
+
+	<!-- Menu layout for Contextual Action Bar in response to file selection in the library (ZimFileSelectFragment.java) -->

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

@@ -56,6 +56,8 @@
   <string name="pref_clear_all_history_summary">Clear recent searches and tabs history</string>
   <string name="all_history_cleared_toast">All History Cleared</string>
   <string name="clear_all_history_dialog_title">Clear All History</string>
+  <string name="share">Share</string>
+  <string name="selected_file_cab_app_chooser_title">Share ZIM files with:</string>
   <string name="delete">Delete</string>
   <string name="delete_specific_search_toast">Recent search removed</string>
   <string name="hint_contents_drawer_message">You can swipe left to view the contents of this article</string>

app/src/main/res/xml/provider_paths.xml

@@ -1,4 +1,9 @@
 <?xml version="1.0" encoding="utf-8"?>
 <paths>
-    <external-path name="external_files" path="."/>
+    <external-path
+        name="external_files"
+        path="." />
+    <root-path
+        name="external_files"
+        path="/storage/" />
 </paths>