@Override
 public void removeMember(User user) {
   service.removeMember(memberGroup, user, null);
   mMembers.remove(user);
   deleteMemberList.remove(user);
   user.isShowDelete = false;
   adapter.notifyDataSetChanged();
 }
 @Override
 public void onBackPressed() {
   if (isInDeleteMode) {
     isInDeleteMode = false;
     mInvitationButton.setText(R.string.crowd_members_invitation);
     for (int i = 0; i < deleteMemberList.size(); i++) {
       User user = deleteMemberList.get(i);
       int index = mMembers.indexOf(user);
       if (index != -1) {
         User search = mMembers.get(index);
         search.isShowDelete = false;
       }
     }
     deleteMemberList.clear();
     adapter.notifyDataSetChanged();
     return;
   }
   super.onBackPressed();
 }