Updating TextView in custom loading dialog

Question

I would like to update the content of the TextView from "Loading.." to "Getting ready" after three seconds. Any advice on how to achieve this?

Thats my Loading Dialog.

public class LoadingDialog {

    private Activity activity;
    private AlertDialog dialog;

    LoadingDialog(Activity activity) {
        this.activity = activity;
    }

    void startLoadingDialog() {
        AlertDialog.Builder builder = new AlertDialog.Builder(activity);
        LayoutInflater inflater = activity.getLayoutInflater();
        builder.setView(inflater.inflate(R.layout.document_request_loading, null));
        builder.setCancelable(false);

        dialog = builder.create();
        dialog.show();
        
    }

    void dismissStartLoadingDialog(){
        dialog.dismiss();
    }
}