javalistcollectionspagination

How to implement pagination on a list?


Is there any library that can be used to implement paging for a list?

Let' assume I have a space of 10 lines, and the user can select if he wants to scroll forward or backward by page (thus +- 10 items). This might eg be controlled by -1, 0, +1.

This is probably much work to build a class that prevents scrolling backward/forward if there are not enough items to display, and to self-save the state on which page the user is currently.

So is there anything?


Solution

  • I've solved this before. I made a static getPages method that breaks a generic collection into a list of pages (which are also lists). I've provided the code below.

    public static <T> List<List<T>> getPages(Collection<T> c, Integer pageSize) {
        if (c == null)
            return Collections.emptyList();
        List<T> list = new ArrayList<T>(c);
        if (pageSize == null || pageSize <= 0 || pageSize > list.size())
            pageSize = list.size();
        int numPages = (int) Math.ceil((double)list.size() / (double)pageSize);
        List<List<T>> pages = new ArrayList<List<T>>(numPages);
        for (int pageNum = 0; pageNum < numPages;)
            pages.add(list.subList(pageNum * pageSize, Math.min(++pageNum * pageSize, list.size())));
        return pages;
    }