RecyclerView - notifyDataSetChanged() - not updating the new list items

[Debdeep Ganguly]

I am removing and adding same list items as required and updating the view. I know I should use

notifyItemInserted()

during adding new elements. When I have less list items on, it gets updated but when there are more items, no change occurs. Can't understand this. Help would be appreciated!

@OnClick(R.id.checkbox_physical_inventory)
    void includeZeroInventoryItems() {
        mItems.clear();
        if (!mZeroInventoryCheckBox.isChecked()) {
             mItems.addAll(queryListItems(false));
        } else {
            mItems.addAll(queryListItems(true));
        }
        setAdapter(mItems);
    }

Here's the adapter:

private void setAdapter(List<Item> items) {
        if (items != null && mPhysicalInventoryAdapter == null) {
            mPhysicalInventoryAdapter = new PhysicalInventoryAdapter(getContext(), items);
            mRecyclerView.setAdapter(mPhysicalInventoryAdapter);
        } else if (mPhysicalInventoryAdapter != null) {
                mPhysicalInventoryAdapter.notifyDataSetChanged();
        }
    }