Does loadDataWithBaseUrl pick all .css and .js files from assets in order to load the page?

Question

so basically I am not understanding if in order for this method to load the page correctly as loadUrl(any_url), I must include all files required (css. js, etc) in the assets while calling:

webview.loadDataWithBaseURL("file:///assets/", htmlData, "text/html", "UTF-8", null);

I ask this because I needed to substitute/add only ONE .CSS file before loading the page, but it seems loadDataWithBaseURL uses only the files in "assets" and the html itself.