If you want to create a function to Show SMS on your device check below simple example. Here I have created a ListAdapter, by using this class sms will be showing on list and in this I have also created a SmsFormat class In which I have set value data. Below code will clearly described you how to make function to show sms.

Step(1)-MainActivity-

public class MainActivity extends ListActivity {

        @Override
        protected void onDestroy() {
            super.onDestroy();
        }

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);

            List<SmsFormat> List = new ArrayList<SmsFormat>();

            Uri uri = Uri.parse("content://sms/inbox");
            Cursor cur = getContentResolver().query(uri, null, null, null, null);
            startManagingCursor(cur);

            if (cur.moveToFirst()) {
                for (int i = 0; i < cur.getCount(); i++) {
                    SmsFormat sms = new SmsFormat();
                    if (cur.getColumnIndexOrThrow("body") > -1) {
                        sms.setBody(cur
                                .getString(cur.getColumnIndexOrThrow("body"))
                                .toString());
                    }
                    if (cur.getColumnIndexOrThrow("address") > -1) {
                        sms.setNumber(cur.getString(
                                cur.getColumnIndexOrThrow("address")).toString());
                    }

                    String name = null;
                    name = Search(cur.getString(
                            cur.getColumnIndexOrThrow("address")).toString());

                    if (name != " ") {
                        sms.setName(name);
                        List.add(sms);
                    }
                    cur.moveToNext();
                }
            }
            cur.close();

            setListAdapter(new ListAdapter(this, List));

        }

        @Override
        protected void onListItemClick(ListView l, View v, int position, long id) {
            SmsFormat sms = (SmsFormat) getListAdapter().getItem(position);
            Log.i("MSG", sms.getBody());

        }

        public String Search(String number) {
            Uri uri = Uri.withAppendedPath(
                    ContactsContract.PhoneLookup.CONTENT_FILTER_URI,
                    Uri.encode(number));
            String name = " ";

            ContentResolver contentResolver = getContentResolver();
            Cursor contactLookup = contentResolver.query(uri, new String[] {
                            BaseColumns._ID, ContactsContract.PhoneLookup.DISPLAY_NAME },
                    null, null, null);

            try {
                if (contactLookup != null && contactLookup.getCount() > 0) {
                    contactLookup.moveToNext();
                    name = contactLookup.getString(contactLookup
                            .getColumnIndex(ContactsContract.Data.DISPLAY_NAME));
                }
            } finally {
                if (contactLookup != null) {
                    contactLookup.close();
                }
            }

            return name;
        }
    }

Step(2)-Create ListAdpter class-

public class ListAdapter extends ArrayAdapter<SmsFormat> {

    private final Context context;
    private final List<SmsFormat> smslist;

    public ListAdapter(Context context, List<SmsFormat> smsList) {
        super(context, R.layout.activity_main, smsList);
        this.context = context;
        this.smslist = smsList;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        LayoutInflater inflater = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);

        View rowView = inflater.inflate(R.layout.activity_main, parent, false);

        TextView senderNumber = (TextView) rowView.findViewById(R.id.textView1);

        senderNumber.setText(smslist.get(position).getName() + "\n"
                + smslist.get(position).getNumber() + "\n" + "\n"
                + smslist.get(position).getBody());

        return rowView;
    }

}

Step(3)-Create SmsFormat class-

public class SmsFormat {
    private String number;
    private String body;
    private String name;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getNumber() {
        return number;
    }

    public void setNumber(String number) {
        this.number = number;
    }

    public String getBody() {
        return body;
    }

    public void setBody(String body) {
        this.body = body;
    }

}

Step(4)Activity_Main layout-

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentRight="true"
        android:layout_alignParentTop="true"
        android:text="Medium Text"
        android:textAppearance="?android:attr/textAppearanceMedium" />

</RelativeLayout>