Remove checkbox selected multiple items from listview android using custom arrayadapter

I have custom arrayadapter for displaying items for listview. I have two textview and one checkbox in item_list.xml file. I want to delete checked items from listview. But problem is when checked multiple items then not properly deleted from position. Below is my source code.

public class MainActivity extends Activity {

    ListView listView;
    Button btnDelete;
    ArrayList<String> items = new ArrayList<String>();
    ArrayList<Integer> ids = new ArrayList<Integer>();
    CustomAdapter adapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        listView = (ListView) findViewById(R.id.listView1);
        btnDelete = (Button) findViewById(R.id.btnDelete);

        for (int i = 0; i < 20; i++) {
            items.add("Chk " + i);
        }

        adapter = new CustomAdapter(MainActivity.this, R.layout.custome_list,
                items);
        listView.setAdapter(adapter);

        btnDelete.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {

                if (ids.size() > 0) {
                    for (int i = 0; i < ids.size(); i++) {
                        items.remove(items.get(ids.get(i)));
//                      items.remove(items.get(adapter.getItemViewType(ids.get(i))));
//                      items.remove(adapter.getItemViewType(ids.get(i)));
                    }

                    adapter.notifyDataSetChanged();
                }
            }
        });
    }

    public class CustomAdapter extends ArrayAdapter<String> {

        List<String> items;
        int resource;

        public CustomAdapter(Context context, int resource, List<String> items) {
            super(context, resource, items);
            this.items = items;
            this.resource = resource;
        }

        @Override
        public View getView(final int position, View convertView, ViewGroup parent) {
            final int pos = position;

            ViewHolder holder = null;

            if (convertView == null) {
                holder = new ViewHolder();
                LayoutInflater inflater = getLayoutInflater();

                convertView = inflater.inflate(resource, null);

                holder.chk = (CheckBox) convertView.findViewById(R.id.chk);
                holder.txt = (TextView) convertView.findViewById(R.id.txt);
                convertView.setTag(holder);
            } else {
                holder = (ViewHolder) convertView.getTag();
            }

            holder.txt.setText(items.get(position));

            // you have to reload the check states
            holder.chk.setOnCheckedChangeListener(null);
            holder.chk.setChecked(ids.contains(position));

            holder.chk
                    .setOnCheckedChangeListener(new OnCheckedChangeListener() {

                        @Override
                        public void onCheckedChanged(CompoundButton buttonView,
                                boolean isChecked) {

                            if (isChecked) {
                                ids.add(position);
                                System.out.println("IDS A: " + ids.toString());
                            } else {
                                if (ids.contains(position)) {
                                    int i = ids.indexOf(position);
                                    ids.remove(i);
                                    System.out.println("IDS R: "
                                            + ids.toString());
                                }
                            }

                        }
                    });
            return convertView;
        }
    }

    public class ViewHolder {
        CheckBox chk;
        TextView txt;
    }
}