为什么List <object>是空的？ （机器人）

Question

我试图在SQL Lite数据库中使用SearchView进行过滤，然后在ListView中显示。我正在使用2 List＆lt;对象＆gt;帮助我做到这一点。首先，我使用bd.buscar（）从SQL Lite中检索数据并传递给我的List＆lt; Produto＆GT; listp。然后我分配给List＆lt; Produto＆gt; Listaux从listp检索的值。 ListView显示数据库中的所有数据。然后我使用SearchView方法onQueryTextChange来做过滤器，ListView变空。 我使用Log来跟踪listp的大小，但是当filterProduto方法启动时，listp变为空。

public class ActivityListaProduto extends Activity {
//ListActivity
protected static final String MsnLog = "log-MeuSQLite";
private ListView my_List;
private ActivityListaProdutoAdapter Adapter;
private SearchView searchView;
private Crud crud;
private Button deletarBt;
List<Produto> listp;
List<Produto> Listaux;

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


    Log.i(MsnLog, " ");
    Log.i(MsnLog, "==========  ActivityListaProduto --- onCreate  ============= ");

    setContentView(R.layout.activity_lista_produto);

    //relate the listView from java to the one created in xml
    my_List = (ListView) findViewById(R.id.mylist);

    //prepare the SearchView
    searchView = new SearchView(this);
    searchView = (SearchView) findViewById(R.id.search);

    caregardb();

    Adapter = new ActivityListaProdutoAdapter(this, Listaux);
    my_List.setAdapter(Adapter);


    // Search
    searchView.setOnQueryTextListener(new Searchable());



    deletarBt = (Button) findViewById(R.id.btnBusca);
    deletarBt.setOnClickListener(new Button.OnClickListener() {
        @Override
        public void onClick(View v) {
            Log.i(MsnLog, " ");
            Log.i(MsnLog, "----------  ActivityListaProduto --- onClick ----------");

            // Search
            Searchable b;
            searchView.setOnQueryTextListener(new Searchable());

            Adapter.notifyDataSetChanged();
            /*
            SearchManager searchManager = (SearchManager) getSystemService(Context.SEARCH_SERVICE);
            SearchView searchView;
            searchView = (SearchView) findViewById(R.id.search);
            Log.i(MsnLog, "searchView =" + searchView);

            searchView.setSearchableInfo(searchManager.getSearchableInfo(getComponentName()));
            Log.i(MsnLog, "searchView =" + searchView.getClass().toString());
            searchView.setQueryHint(getResources().getString(R.string.search_hint));
            Log.i(MsnLog, " ---- > vai para a tela SearchableActivity ");

            //ActivityListaProdutoAdapter.this.notifyDataSetChanged();

            //Adapter.notifyDataSetChanged();
            //Log.i(MsnLog, " ---- > Adapter.notifyDataSetChanged()");
            */
        }
     });

}

public void caregardb(){
    Crud bd = new Crud(this);
    listp = bd.buscar();

    Log.i(MsnLog, "onCreate -- listp.size()= "+ listp.size());

    Listaux = listp;
    Log.i(MsnLog, "onCreate -- Listaux.size() 2= "+ Listaux.size());
    Log.i(MsnLog, "onCreate -- listp.size()= "+ listp.size());
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.menu_activity_lista_produto, menu);
    // test
    /*
    SearchManager searchManager = (SearchManager) getSystemService(Context.SEARCH_SERVICE);
    SearchView searchView = (SearchView) menu.findItem(R.id.menu_search).getActionView();
    searchView.setSearchableInfo(searchManager.getSearchableInfo(getComponentName()));
    searchView.setIconifiedByDefault(false);
    */
    // Search
    SearchManager searchManager = (SearchManager) getSystemService(Context.SEARCH_SERVICE);
    SearchView searchView;
    MenuItem item = menu.findItem(R.id.menu_search);
    if( Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB ){
        searchView = (SearchView) item.getActionView();
    }
    else{
        searchView = (SearchView) MenuItemCompat.getActionView(item);
    }
    searchView.setSearchableInfo( searchManager.getSearchableInfo( getComponentName() ) );
    searchView.setQueryHint( getResources().getString(R.string.search_hint) );


    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.

    switch (item.getItemId()) {
        case R.id.menu_search:
            onSearchRequested();
            return true;
        default:
            return false;
    }
    /*
    int id = item.getItemId();
    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
        return true;
    }
    */

    //return super.onOptionsItemSelected(item);
}

public class Searchable implements SearchView.OnQueryTextListener {

    @Override
    public boolean onQueryTextSubmit(String query) {
        Log.i(MsnLog, "----------  Searchable --- onQueryTextSubmit ----------");
        Log.i(MsnLog, "onQueryTextSubmit(String" + query + ") ");
        filterProduto(query);

        return false;
    }

    @Override
    public boolean onQueryTextChange(String newText) {
        Log.i(MsnLog, "----------  Searchable --- onQueryTextChange ----------");
        Log.i(MsnLog, "onQueryTextChange(String " + newText + " ) ");
        filterProduto(newText);
        return false;
    }

    public void filterProduto( String q ){
        Log.i(MsnLog, " ");
        Log.i(MsnLog, "----------  Searchable --- filterProduto ----------");
        Log.i(MsnLog, " String q = "+ q);

        Listaux.clear();
        Log.i(MsnLog, "filterProduto -- listp.size()= "+ listp.size());
        for( int i = 0, tamI = listp.size(); i < tamI; i++ ){
            Log.i(MsnLog, " int i = 0,"+ tamI +" = "+listp.size()+ "; "+ i + " < " +tamI+ "; "+i+"++ ");
            if( listp.get(i).getNmProduto().toLowerCase().startsWith( q.toLowerCase() ) ){
                Log.i(MsnLog, "listp.get(i) = "+ listp.get(i));
                Listaux.add( listp.get(i) );
                Log.i(MsnLog, "Listaux.add) = "+ listp.get(i));
            }
        }

        if( Listaux.isEmpty() ){
            Log.i(MsnLog, "Lista - Listaux Vasia");
        }
        Log.i(MsnLog, "Listaux " + Listaux.getClass());
        Adapter.notifyDataSetChanged();
    }
}

}