private void doSearch(String keyword) {
   mProgressBar.setVisibility(View.VISIBLE);
   mAdapter.clearItems();
   Book.searchBooks(
       keyword,
       new Book.IBookResponse<List<Book>>() {
         @Override
         public void onData(List<Book> books) {
           mProgressBar.setVisibility(View.GONE);
           startFABAnimation();
           mAdapter.updateItems(books, true);
         }
       });
 }