Android AlertDialog with custom view: get input data

I have an application with an AlertDialog that shows a single EditText. I followed the Android developers guide to do it, but I can't find how to get the data entered by the user.

The custom layout only has an EditText:

<EditText
    android:id="@+id/license_value"
    android:inputType="text"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:hint="@string/license" />

I'm using a DialogFragment to create the dialog. To get the data back when the user clicks the ok button I'm using an interface.

public class EditLicenseDialogFragment extends DialogFragment {

    public interface EditLicenseDialogListener {
        public void onDialogPositiveClick(DialogFragment dialog, String value);
    }

    private EditLicenseDialogListener mListener;

    // Override the Fragment.onAttach() method to instantiate the NoticeDialogListener
    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
        // Verify that the host activity implements the callback interface
        try {
            // Instantiate the NoticeDialogListener so we can send events to the host
            mListener = (EditLicenseDialogListener) activity;
        } catch (ClassCastException e) {
            // The activity doesn't implement the interface, throw exception
             throw new ClassCastException(activity.toString()
                    + " must implement NoticeDialogListener");
        }
    }

    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        // Use the Builder class for convenient dialog construction
        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());

        builder.setTitle(R.string.new_license);

        LayoutInflater inflater = getActivity().getLayoutInflater();

        builder.setView(inflater.inflate(R.layout.edit_license, null))

        .setPositiveButton(R.string.ok, new Dia