registerContentObserver() on raw SQLite Cursor

All of the examples I've seen of using registerContentObserver() do so through a ContentProvider interface. But Cursor has a registerContentObserver() call, so I figured maybe the Android folks have put together some deep magic that would allow for getting updates on a SQLite cursor when one of the rows from an active result set changed. Either I'm doing it wrong, or there is no such magic. Here's the code I'm working with, the expectation being that when I click on the button to update the value in row #1 I would get an onChange() callback. Any ideas?

public class MainActivity extends Activity {
    private static final String DATABASE_NAME = "test.db";
    public static final String TAG = "dbtest";

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        Button make = (Button)findViewById(R.id.btn_make_record);
        make.setOnClickListener(new OnClickListener() {
            public void onClick(View v) {
                MyOpenHelper oh = new MyOpenHelper(v.getContext());
                SQLiteDatabase wdb = oh.getWritableDatabase();
                ContentValues cv = new ContentValues();
                cv.put("value", String.valueOf(System.currentTimeMillis()));
                if (wdb.insert(MyOpenHelper.TABLE_NAME, null, cv) == -1) {
                    Log.d(TAG, "Unable to insert row");
                } else {
                    Log.d(TAG, "Inserted row ");
                }
                wdb.close();
            }
        });

        Button update = (Button)findViewById(R.id.btn_update_record);
        update.setOnClickListener(new OnClickListener() {   
            public void onClick(View v) {
                MyOpenHelper oh = new MyOpenHelper(v.getContext());
                SQLiteDatabase wdb = oh.getWritable