how to solve change of background image when scroll the listview?

I have an application in which i use the listview which have two part one is section part and other part is item part. But i want to make the listview in group with rounded corner depending on sectioned information. Suppose the section part contain the character A, all the information regarding A are display under the sction A with rounded background again if the header contain B then all the information regarding B are display under B with rounded corner and so on. I will give you my adapter class where i want to make the rounded block according to the sectioned information.But i use two different custom view one is for section and second one is for section item. I write the condition in given code which display the block with rounded corner according to the section text. But rounded background shape display only first time when i move the listview it was remove from the background.

in my following code i was mention some condition.So what is do in the condition i explain it.

    **variables:**

    size- it indicate the how much data contain in a particular sectioned.
    index- it indicate the position of the array.
    arr- this is an array.
    counter- it indicate the position where i set the rounded shape.            


    This is my adapter class:  

        public class EntryAdapter extends ArrayAdapter {

            private Context context;
            public ArrayList items;
            private LayoutInflater  vi;
            public int arr[]=new int[26];
            public int sum=0,size,counter=0,index=0;
            public EntryAdapter(Context context,ArrayList items,int arr[],int size) {
                super(context,0, items);
                this.context = context;
                this.items = items;
                this.arr=arr;
                vi = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                this.size=size;
            }


            @Override
            public View getView(int position, View convertView, ViewGroup parent) {
                View v = convertView;
                ViewHolder1     holder1=new ViewHolder1();
                final Item i = (Item) items.get(position);
                if (i != null) {
                    if(i.isSection()){
                        SectionItem si = (SectionItem)i;
                        v = vi.inflate(R.layout.list_item_section, null);

                        v.setOnClickListener(null);
                        v.setOnLongClickListener(null);
                        v.setLongClickable(false);

                        holder1.sectionView = (TextView) v.findViewById(R.id.list_item_section_text);
                        holder1.sectionView.setText(si.getTitle());

                    }else{
                        EntryItem ei = (EntryItem)i;
                        if (v!=null) {
                            v = vi.inflate(R.layout.list_item_entry, null);
                            holder1.title = (TextView)v.findViewById(R.id.list_item_entry_title);
                            holder1.ll=(LinearLayout)v.findViewById(R.id.ll);
                        }

                        counter++;
                        holder1.title.setText(ei.title);
                        if(counter==arr[index])
                        {
                            counter=0;
                            if(index<size){
                                index++;
                            }   
                            holder1.ll.setBackgroundResource(R.drawable.list_rounded_corner_shape);
                            Log.v("LOG ", "if ");
                        }
                    }
                }
                return v;
            }



            class ViewHolder1{
                TextView sectionView,title;
                LinearLayout ll;
            }

        }