Android get sms from inbox, optimized way to read all messages and group them

Hi am implementing a SMS App, now am able to retrieve all messages with their respective contact info like display name, photo uri.. and am displaying them in a custom list where on item click takes you to respective discussion. Here my issues is the time taking to sync all these messages,

1. I need to optimize this time.
2. Each time i send a new message in the discussion view and go back to recent chats i need to only update the particular item, not the whole list.

Here's my code:

ReadSMS.java:

public class ReadSMS {

    ArrayList<HashMap<Contact, ArrayList<OneComment>>> recentChats;

    Application _context;

    public ReadSMS(Application context) {
        this._context = context;
        this.recentChats = ((ChatApplication) _context).getChats();
    }

    public ArrayList<HashMap<Contact, ArrayList<OneComment>>> getSMS() {

        // Init
        ArrayList<SmsMsg> smsMsgs = new ArrayList<SmsMsg>();
        TreeSet<Integer> threadIds = new TreeSet<Integer>();

        Uri mSmsinboxQueryUri = Uri.parse("content://sms");
        Cursor cursor = _context.getContentResolver().query(
                mSmsinboxQueryUri,
                new String[] { "_id", "thread_id", "address", "date", "body",
                        "type" }, null, null, null);

        String[] columns = new String[] { "address", "thread_id", "date",
                "body", "type" };
        if (cursor.getCount() > 0) {

            while (cursor.moveToNext()) {

                SmsMsg smsMsg = new SmsMsg();

                String address = null, displayName = null, date = null, msg = null, type = null, threadId = null;
                Uri photoUri = null;

                threadId = cursor.getString(cursor.getColumnIndex(columns[1]));

                type = cursor.getString(cursor.getColumnIndex(columns[4]));

                if (Integer.parseInt(type) == 1 || Intege