Ensuring that bookmark export failures are handled

app/src/main/java/acr/browser/lightning/fragment/BookmarkSettingsFragment.java

@@ -211,6 +211,17 @@ public class BookmarkSettingsFragment extends PreferenceFragment implements Pref
                                                             + ' ' + exportFile.getPath());
                                                     }
                                                 }
+
+                                                @Override
+                                                public void onError(@NonNull Throwable throwable) {
+                                                    Log.e(TAG, "onError: exporting bookmarks", throwable);
+                                                    Activity activity = getActivity();
+                                                    if (activity != null) {
+                                                        Utils.createInformativeDialog(activity, R.string.title_error, R.string.bookmark_export_failure);
+                                                    } else {
+                                                        Utils.showToast(mApplication, R.string.bookmark_export_failure);
+                                                    }
+                                                }
                                             });
                                     }
                                 });

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

@@ -176,6 +176,7 @@
     <string name="export_bookmarks">Export bookmarks to backup</string>
     <string name="import_backup">Import bookmarks from backup</string>
     <string name="bookmark_export_path">Bookmarks exported to</string>
+    <string name="bookmark_export_failure">Sorry, bookmarks could not be exported!</string>
     <string name="bookmark_settings">Bookmark Settings</string>
     <string name="import_bookmark_error">Could not import bookmarks from file</string>
     <string name="title_chooser">Choose a file</string>