@Override
 protected void initView() {
   super.initView();
   ExpandableListView expandableListView =
       (ExpandableListView) findViewById(R.id.elv_explandablelist);
   expandableListView.setAdapter(mAdapter);
 }
 @Override
 protected void assignView() {
   super.assignView();
   List<String> headerNames = new ArrayList<>();
   headerNames.add(STICKY_HEADER);
   headerNames.add(NORMAL_HEADER);
   headerNames.add(BOTTOM);
   mAdapter = new ListPostInSectionAdapter(this, headerNames, null, this);
 }
 @Override
 public void onRefresh() {
   super.onRefresh();
   new Handler()
       .postDelayed(
           new Runnable() {
             @Override
             public void run() {
               mRefreshLayout.setRefreshing(false);
             }
           },
           1000);
 }