How to Ensure Accurate Search Text Highlighting in RecyclerView with ListAdapter?

Fixing Search Text Highlighting in RecyclerView with ListAdapter

When using a SearchView with a RecyclerView powered by a ListAdapter, it's crucial to properly highlight search results. However, a common issue arises where the first CardView in the list or others below may not highlight the search text, or highlighting occurs inconsistently.

The reason for this behavior lies in the background thread used by ListAdapter to update views, potentially causing the dataset to be unavailable during initial rendering. To resolve this, consider the following measures:

• Use item diffing: Ensure that submitted lists are compared to determine which items have changed, triggering the appropriate view updates.
• Modify the Card model: Introduce a searchString property to the Card model. When filtering, create new Card instances with updated search strings. This triggers a complete data change, forcing ListAdapter to call onBindViewHolder() for each existing item.

Example Code

// In the ListAdapter
public class CardRVAdapter extends ListAdapter<Card, CardRVAdapter.ViewHolder> {

    private String searchString = "";

    public void setFilter(List<Card> newSearchList, String searchText) {
        if (newSearchList != null && !newSearchList.isEmpty()) {
            this.searchString = searchText;
            List<Card> filteredList = new ArrayList<>();
            for (Card card : newSearchList) {
                Card newCard = new Card(card);
                newCard.setSearchString(searchText);
                filteredList.add(newCard);
            }
            submitList(filteredList);
        }
    }

    @Override
    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
        final Card card = getCardAt(position);
        if (card != null) {
            holder.bindData(card, position);
        }
    }
}

// In the Card model
public class Card {

    private String searchString;

    public Card(String todo, String searchString) {
        // Constructor with both original todo and search string
    }

    public String getSearchString() {
        return searchString;
    }

    public void setSearchString(String searchString) {
        this.searchString = searchString;
    }
}

By implementing these changes, you can accurately highlight search text in RecyclerView with ListAdapter, regardless of scrolling or initial rendering.

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