Custom Expandable ListView issue with child view

I have custom expandable list view ,in which parent view contains one text view and button.When click on parent button a custom child view appears and that contains another button and 3 edit texts.When click on first Edittext in child view a datepicker dialog will appear.My problem is I am not able to set the date picker values to the edit text , and also get the edit text values on child view button click didnt return any value. Can someone help me please?

Activity.java

private void prepareListData() { listDataHeader = new ArrayList(); listDataChild = new HashMap>();

    // Adding parent data
    listDataHeader.addAll(selectdMedicines);
    int count = listDataHeader.size();
    ArrayList<String> child=new ArrayList<String>();
    for (int i = 0; i < count; i++) {
        child.add("med"+i);
    }

    for (int i = 0; i < count; i++) {
    List<String> name = new ArrayList<String>();
    listDataChild.put(listDataHeader.get(i), name); 
     name.add("Medicine Info");
    }

    listAdapter = new ExpandableListAdapter(MyMedication.this,
            listDataHeader, listDataChild);

    // setting list adapter
    expListView.setAdapter(listAdapter);
}

ExpandableListAdapter.java

@Override public View getChildView(int groupPosition, final int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {

    child=convertView;
    final String childText = (String) getChild(groupPosition, childPosition);

    final int posi = groupPosition;
    if (convertView == null) {
        LayoutInflater infalInflater = (LayoutInflater) this._context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        convertView = infalInflater.inflate(R.layout.list_item, null);
    }

    TextView txtListChild = (TextView) convertView
            .findViewById(R.id.textEx);
    txtListChild.setText(childText);

    editMedDt = (EditText) convertView
            .findViewById(R.id.medstrdt);
     editDose = (EditText) convertView
            .findViewById(R.id.dose);
    editFreq = (EditText) convertView
            .findViewById(R.id.frequency);

    ImageView childSave = (ImageView) convertView
            .findViewById(R.id.imgSave);
    editMedDt.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View arg0) {
            // TODO Auto-generated method stub
            InputMethodManager imm = (InputMethodManager) _context.getSystemService(Context.INPUT_METHOD_SERVICE);
            imm.toggleSoftInput(InputMethodManager.HIDE_IMPLICIT_ONLY, 0);
            Toast.makeText(_context, "start dt", Toast.LENGTH_LONG).show();
        //  ((Activity) ExpandableListAdapter.this._context)
            //((Activity) ExpandableListAdapter.this._context).showDialog(1);
            showDtDialog();
        }
    });
    childSave.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View arg0) {
            // TODO Auto-generated method stub
        //  Toast.makeText(_context, "" + posi, Toast.LENGTH_LONG).show();
            medName=_listDataHeader.get(posi);
            medStrDt=editMedDt.getText().toString();
             dose=editDose.getText().toString();
            frequency=editFreq.getText().toString();
            Toast.makeText(_context, medName +"\n"+ medStrDt+"\n"+dose+"\n"+frequency, Toast.LENGTH_LONG).show();

        }
    });

    return convertView;
}