Custom Grid View with Row span and Column span

Question

i am trying to implement a grid view which has the Graphical view as follows. I have gone through various blogs and S.O questions, and unfortunately i am not able to provide

Answer 1

This is a particular solution for 3 column grids with featured items that span 2x2 grids.

public class GridAdapter extends ArrayAdapter {
    public GridAdapter(Context context, int itemViewResId, List things) {
        super(context, itemViewResId, buildGridItems(things));
    }

    /**
     * Assumes 3 column layout. A list of indices that shows a large
     * item on the right of 1st row, then alternating on every 3rd row 
     * to the left and then right. The large item should occupy a 2x2 grid.
     *
     *   X O O
     *   X O O
     *   X X X
     *   X X X
     *   O O X
     *   O O X
     *   X X X
     *   X X X
     *   X O O
     *   X O O
     *   X X X
     *
     * The indices where the large featured items are in item list is 
     * 1, 9, 19, 27, 37, 45, 55, ...         
     */
    protected static List getFeaturedIndex(int total) {
        int pos = 1;
        ArrayList index = new ArrayList();
        if (pos + 1 < total) {
            index.add(pos);
        }
        for (int i = 0; pos < total; i++) {
            int inc = i % 2 == 0 ? 8 : 10;
            pos += inc;
            if (pos + 1 < total) {
                index.add(pos);
            }
        }
        return index;
    }

    protected static List buildGridItems(List things) {
        ArrayList items = new ArrayList();
        List featuredIndex = getFeaturedIndex(things.size());
        ArrayList featured = new ArrayList();
        for (int i = 0, k = things.size(); i < k; i++) {
            GridItem item = new GridItem(things.get(i));
            if (featuredIndex.contains(i)) {
                item.feature = true;
                featured.add(item);
            }
            items.add(item);
        }
        for (GridItem feature : featured) {
            int index = items.indexOf(feature);
            GridItem shim = new GridItem(feature.getModel());
            shim.shim = true;
            items.add(index + 1, shim);
            items.add(index + 3, shim);
            items.add(index + 4, shim);
        }
        return items;
    }

    @Override
    public int getItemViewType(int position) {
        return getItem(position).shim ? 0 : 1;
    }

    @Override
    public int getViewTypeCount() {
        return 2;
    }

    public View getView(int position, View convertView, ViewGroup parent) {
        if (convertView == null) {
            convertView = new View(getContext());
        }
        GridItem item = getItem(position);
        if (item.feature) {
            convertView.setLayoutParams(new LayoutParams(400,300));
        } else {
            convertView.setLayoutParams(new LayoutParams(200,150));
        }
        if (item.shim) {
            convertView.setVisibility(View.GONE);
        }
        return convertView;
    }

    public static class GridItem {
        private String mItem;
        private boolean shim = false;
        private boolean feature = false;

        public GridItem(String item) {
            mItem = item;
        }
    }
}

The idea is to wrap the item list with GridItem with a feature and shim flags that determine how the views should behave.

The method getFeaturedIndex() calculates which items in the original list should be featured. Then in the buildGridItems() we take 2 steps. First, flag all the items that are featured (and keep a list of these items). Afterwards, for each of these featured items, add 3 shims (+1, +3 and +4) relative to the featured item.

In the getView() for featured items, we set the appropriate dimensions as 2x2 of the normal items. For shim items, set the visibility to GONE.