I tried this:
Activity class:
public MyActivity extends Activity implements onClickListener {
     TextView item;
     public void onCreate(Bundle state) {
        super.onCreate(savedState);
        setContentView(R.layout.main);
        item = (TextView) findViewById(R.id.id_item);
        item .setOnClickListener(this);
     }
     public void onClick(View v) {
          new MyBuilder(this).show();
          updateUI();
     }
     private void updateUI() {
          item.setText(ItemMap.item);
     }
}

Builder class:

public class MyBuilder extends AlertDialog.Builder implements OnClickListener{

Context context;
String[] items = {"pen", "pencil", "ruler"};
public MyBuilder(Context context) {
    super(context);
    super.setTitle("Select Item");
    this.context = context;
    super.setSingleChoiceItems(items, 0, this);

}

@Override
public void onClick(DialogInterface dialog, int position) {
    ItemMap.item = items[position];
    dialog.dismiss();
}
}

Mapping class:

public class ItemMap {
    public static String item;
}

public MyActivity extends Activity implements onClickListener, AlertBuilderCallback {
     TextView item;
     public void onCreate(Bundle state) {
        super.onCreate(savedState);
        setContentView(R.layout.main);
        item = (TextView) findViewById(R.id.id_item);
        item .setOnClickListener(this);
     }
     public void onClick(View v) {
          new MyBuilder(this).addCallback(this).show();
          updateUI();
     }
     public void updateUI() {
          item.setText(ItemMap.item);
     }
}

public interface AlertBuilderCallback {
    public void updateUI();
}

public class MyBuilder extends AlertDialog.Builder implements OnClickListener{

    Context context;
    String[] items = {"pen", "pencil", "ruler"};
    public MyBuilder(Context context) {
        super(context);
        super.setTitle("Select Item");
        this.context = context;
        super.setSingleChoiceItems(items, 0, this);
    }

    public MyBuilder addCallback(AlertBuilderCallback callBack) {
        this.callBack = callBack;
        return this;
    }

    @Override
    public void onClick(DialogInterface dialog, int position) {
        ItemMap.item = items[position];
        if(this.callBack != null) {
            this.callBack.updateUI();
        }
        dialog.dismiss();
    }
}

public class ItemMap {
    public static String item;
}

@Override
public void onClick(DialogInterface dialog, int position) {
   ItemMap.item = items[position];
   updateUI();
   dialog.dismiss();