CursorLoader继承与AsycTaskLoader，内部自带ContentObserver。我们可以用它来读取数据库，并自动检测数据源的更新。

下面是读取短信的例子

public class LoadersActivity extends AppCompatActivity implements LoaderManager.LoaderCallbacks
    
      {    private ListView mListView;    private MyAdapter mAdapter;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_loaders);        mListView = (ListView) findViewById(R.id.lv);        LoaderManager loaderManager = getSupportLoaderManager();        loaderManager.initLoader(0, null, this);    }    @Override    public Loader onCreateLoader(int id, Bundle args) {        Uri CONTACT_URI = Uri.parse("content://sms/");        CursorLoader cursorLoader = new CursorLoader(this, CONTACT_URI, null,                null, null, null);        return cursorLoader;    }    @Override    public void onLoadFinished(Loader loader, Cursor data) {        data.moveToFirst();        mAdapter = new MyAdapter(this, data);        mListView.setAdapter(mAdapter);    }    @Override    public void onLoaderReset(Loader loader) {    }}class MyAdapter extends BaseAdapter {    private List
     
       mDataList;    private Context context;    private Cursor cursor;    private class ViewHolder {        TextView textView;    }    public MyAdapter(Context context, Cursor cursor) {        this.context = context;        this.cursor = cursor;    }    public void setDataList(List
      
        dataList) {        this.mDataList = dataList;    }    @Override    public int getCount() {        return cursor.getCount();    }    @Override    public Object getItem(int position) {        return null;    }    @Override    public long getItemId(int position) {        return position;    }    @Override    public View getView(int position, View convertView, ViewGroup parent) {        ViewHolder viewHolder;        View view = convertView;        if (view == null) {            view = LayoutInflater.from(context).inflate(R.layout.item_cursor_loader, null);            viewHolder = new ViewHolder();            viewHolder.textView = (TextView) view.findViewById(R.id.textview);            view.setTag(viewHolder);        } else {            viewHolder = (ViewHolder) view.getTag();        }        cursor.moveToPosition(position);        viewHolder.textView.setText(cursor.getString(2));        return view;    }}