Customizing RecyclerView with Headers and Footers

When working with RecyclerView, the need to display headers and footers often arises. This enhances the user experience by providing additional information or navigation elements.

Adding a Header

To add a header, inflate a custom layout and pass it to the LayoutManager using the addView() method. For instance, in the provided code snippet, the following lines add a header:

LayoutInflater inflater = (LayoutInflater) getActivity().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
headerPlaceHolder = inflater.inflate(R.layout.view_header_holder_medium, null, false);
layouManager.addView(headerPlaceHolder, 0);

However, in order for this to work, the LayoutManager must have an addView() method that takes two arguments: the view to add and its position within the RecyclerView. Therefore, this approach assumes you have a custom LayoutManager that supports adding headers.

Adding a Footer

A similar approach can be used to add a footer. However, instead of using addView(), you can use addFooterView() or create a custom adapter that handles the footer and normal items.

Using a Custom Adapter

An alternative solution is to create a custom adapter that handles both the header and footer. The adapter can then return the correct number of items, including the header and footer, and inflate the header and footer views in the onCreateViewHolder() method. An example implementation:

    // Define a constant for the footer view type
    private static final int FOOTER_VIEW = 1;

    // Override the onCreateViewHolder() method
    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        if (viewType == FOOTER_VIEW) {
            // Inflate the footer view
            View footerView = LayoutInflater.from(context).inflate(R.layout.list_item_footer, parent, false);
            return new FooterViewHolder(footerView);
        } else {
            // Inflate the normal view
            View normalView = LayoutInflater.from(context).inflate(R.layout.list_item_normal, parent, false);
            return new NormalViewHolder(normalView);
        }
    }

    // Override the getItemViewType() method
    @Override
    public int getItemViewType(int position) {
        if (position == data.size()) {
            // Return the FOOTER_VIEW type for the footer
            return FOOTER_VIEW;
        }
        return super.getItemViewType(position);
    }

Supporting Multiple Headers and Footers

The approaches described above can be adapted to support multiple headers and footers. You simply need to modify the adapter or custom LayoutManager to handle the additional headers and footers.

Handling GridLayoutManager

To support a GridLayoutManager, you can use a GridLayoutManager.SpanSizeLookup to specify the number of spans that each item should occupy. For example:

// Create a SpanSizeLookup
GridLayoutManager.SpanSizeLookup spanSizeLookup = new GridLayoutManager.SpanSizeLookup() {
    @Override
    public int getSpanSize(int position) {
        // Return 1 for normal items, and the number of columns for the footer
        if (position == data.size()) {
            return gridLayoutManager.getSpanCount();
        }
        return 1;
    }
};

// Set the SpanSizeLookup to the GridLayoutManager
gridLayoutManager.setSpanSizeLookup(spanSizeLookup);

This approach will ensure that the footer occupies the entire width of the RecyclerView.