Question

Is it possible to create a callback function ArrayList add/remove method.

ArrayList will contain image urls and I would like to run my code (update UI) as soon as I add/remove new element.

Answer 1

Encapsulate the list in your own object, and do whatever you want before or after adding an element into the list:

public class UrlContainer {

    private List<String> urls = new ArrayList<String>();

    public void add(String url) {
        doSomething();
        urls.add(url);
        doSomethingElse();
    }

    ...
}