Search controls in a separate class from the main activity

Question

I need to search the controls to change values in the layout. But passing the context by parameter to the class it does not find the controls declared in xml returning null for each cast made.

The class where I am trying to recover this data extends Asynctask:

public class WSCatalogo91 extends AsyncTask<Void, ProgressAux, Boolean> 

private ProgressBar mProgressBar;
private TextView mProgressText;

public WSCatalogo91(WSCatalogo91Listener listener) throws SQLException {
        this.listener = listener;
        dh = new DatabaseHelper((Activity) listener);
        confDao = new ConfiguracaoDao(dh.getConnectionSource());
        pDao = new ProdutoDao(dh.getConnectionSource());

        mProgressBar = (ProgressBar) ((Activity) listener).findViewById(R.id.progressBar);
        mProgressText = (TextView) ((Activity) listener).findViewById(R.id.progressBarTextView);
        auxProgresso = new ProgressAux();
    }

mProgressBar and mProgressText are null, but my context there is not null, so much so that it is being used on the top lines perfectly. Follow the xml code where I declare the ids.

<TextView android:text="@string/progressBar" android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        android:id="@+id/progressBarTextView"
        android:maxWidth="400dp"
        android:maxHeight="400dp"/>

    <ProgressBar
        style="?android:attr/progressBarStyleHorizontal"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/progressBar"
        android:indeterminate="false"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="165dp"
        android:minWidth="300dp" />