Android多层expandablelistview

Question

这里我创建了一个可扩展的列表视图，包括成功的子项和父项。现在我想再添加一个中间孩子到我的程序中

parent1
     middlechild11
                child111
                child112  
      middlechild12
                child121
                child122  
  parent2

同样，请帮我以这种方式更新我的代码。这是我的完整代码

  expandableListView = (ExpandableListView) findViewById(R.id.list);
  expandableListDetail =getData();
  expandableListTitle = new ArrayList(expandableListDetail.keySet());
  expandableListAdapter = new com.example.janamytri.ExpandableListAdapter(this, expandableListTitle, expandableListDetail);
  expandableListView.setAdapter(expandableListAdapter);

  expandableListView.setOnGroupExpandListener(new OnGroupExpandListener() {

      @Override
      public void onGroupExpand(int groupPosition) {

          alert();
          Toast.makeText(getApplicationContext(),
                  expandableListTitle.get(groupPosition) + " List Expanded.",
                  Toast.LENGTH_SHORT).show();
      }


  expandableListView.setOnGroupCollapseListener(new OnGroupCollapseListener() {

      @Override
      public void onGroupCollapse(int groupPosition) {
          Toast.makeText(getApplicationContext(),
                  expandableListTitle.get(groupPosition) + " List Collapsed.",
                  Toast.LENGTH_SHORT).show();

      }
  });

  expandableListView.setOnChildClickListener(new OnChildClickListener() {
      @Override
      public boolean onChildClick(ExpandableListView parent, View v,
                                  int groupPosition, int childPosition, long id) {
          Toast.makeText(
                  getApplicationContext(),
                  expandableListTitle.get(groupPosition)
                          + " -> "
                          + expandableListDetail.get(expandableListTitle.get(childPosition)), Toast.LENGTH_SHORT
          )
                  .show();
          return false;
      }
  });   

  public static HashMap getData() {
        HashMap expandableListDetail = new HashMap();

        List technology = new ArrayList();
        technology.add(arrayString);




        List entertainment = new ArrayList();

        technology.add(arrayString1);

        List science = new ArrayList();

        science.add("list1");


        expandableListDetail.put("PALAKKAD", technology);
        expandableListDetail.put("THRISSUR", entertainment);
        expandableListDetail.put("ERNAMKULAM", science);
        expandableListDetail.put("CALICUT", technology);
        expandableListDetail.put("TRIVANDRUM", entertainment);

        return expandableListDetail;
    }

这是我的ExpandableListAdapter.class

 public class ExpandableListAdapter extends BaseExpandableListAdapter {

 private Context context;
    private List<String> expandableListTitle;
    private HashMap<String, List<String>> expandableListDetail;

    public ExpandableListAdapter(Context context, List<String> expandableListTitle,
                                 HashMap<String, List<String>> expandableListDetail) {
        this.context = context;
        this.expandableListTitle = expandableListTitle;
        this.expandableListDetail = expandableListDetail;
    }

    @Override
    public Object getChild(int listPosition, int expandedListPosition) {
        return this.expandableListDetail.get(this.expandableListTitle.get(listPosition))
                .get(expandedListPosition);
    }

    @Override
    public long getChildId(int listPosition, int expandedListPosition) {
        return expandedListPosition;
    }

    @Override
    public View getChildView(int listPosition, final int expandedListPosition,
                             boolean isLastChild, View convertView, ViewGroup parent) {
        final String expandedListText = (String) getChild(listPosition, expandedListPosition);
        if (convertView == null) {
            LayoutInflater layoutInflater = (LayoutInflater) this.context
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = layoutInflater.inflate(R.layout.child, null);
        }
        TextView expandedListTextView = (TextView) convertView
                .findViewById(R.id.childtxt);
        expandedListTextView.setText(expandedListText);
        return convertView;
    }

    @Override
    public int getChildrenCount(int listPosition) {
        return this.expandableListDetail.get(this.expandableListTitle.get(listPosition))
                .size();
    }

    @Override
    public Object getGroup(int listPosition) {
        return this.expandableListTitle.get(listPosition);
    }

    @Override
    public int getGroupCount() {
        return this.expandableListTitle.size();
    }

    @Override
    public long getGroupId(int listPosition) {
        return listPosition;
    }

    @Override
    public View getGroupView(int listPosition, boolean isExpanded,
                             View convertView, ViewGroup parent) {
        String listTitle = (String) getGroup(listPosition);
        if (convertView == null) {
            LayoutInflater layoutInflater = (LayoutInflater) this.context.
                    getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = layoutInflater.inflate(R.layout.parent, null);
        }
        TextView listTitleTextView = (TextView) convertView
                .findViewById(R.id.parenttxt);
        listTitleTextView.setTypeface(null, Typeface.BOLD);
        listTitleTextView.setText(listTitle);
        return convertView;
    }

    @Override
    public boolean hasStableIds() {
        return false;
    }

    @Override
    public boolean isChildSelectable(int listPosition, int expandedListPosition) {
        return true;
    }

   }