android - Highlight search results in ListView

Question

I have a ListView with Strings. With the below code I can highlight search results, but the user must type the words to search case sensitive. How can I implement a none - case sensitive highlighting of search results for example like the native Android Contact search?

Here is my code for Highlighting. I extend the ArrayAdapter and implement customized filter to get the string to search. In the getView method I check if my String in ListView contains the prefixString and highlight it.

public class HighlightListAdapter extends ArrayAdapter {
    ArrayList<String> objects;
    final Object mLock =new Object();
    private ArrayList<String> mOriginalValues;
    private ArrayFilter filter;
    private String prefixString;
    public AuthorsListAdapter(Context context, int textViewResourceId,  ArrayList<String> objects) {
        super(context, textViewResourceId, objects);
        this.objects = objects;
    }



    class ViewHolder{
        TextView author;

    }

    public View getView(final int position, View convertView, ViewGroup parent){

        // assign the view we are converting to a local variable
        View v = convertView;
        ViewHolder holder = null;

        // first check to see if the view is null. if so, we have to inflate it.
        // to inflate it basically means to render, or show, the view.
        LayoutInflater inflater = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        if (v == null) {
            holder = new ViewHolder();
            v = inflater.inflate(R.layout.author_list_item, null);
            holder.author =(TextView) v.findViewById(R.id.author_list_item_text);
            v.setTag(holder);

        }else{
            holder = (ViewHolder) v.getTag();

        }


         final String author = objects.get(position);        
        if (author != null) {


        holder.author.setText(author);
        if(prefixString !=null && prefixString.length()>1){
            String s =  author;



        **if(s.contains(prefixString)){
            String rep = s.replace(prefixString,    "<b><font color=#2825A6>"+ prefixString+ "</font></b>");
            holder.author.setText(Html.fromHtml(rep));
        }** // higlight 



        }

            }

        return v;
    }
    @Override
    public int getCount() {
        // TODO Auto-generated method stub
        return objects.size();
    }



     @Override
    public Filter getFilter() {
        // TODO Auto-generated method stub
        if(filter == null){
            filter =new ArrayFilter();
        }
        return filter;
    }



    @Override
    public Object getItem(int position) {
        // TODO Auto-generated method stub
        return this.objects.get(position);
    }



    private class ArrayFilter extends Filter {
            @Override
            protected FilterResults performFiltering(CharSequence prefix) {
                FilterResults results = new FilterResults();

                if (mOriginalValues == null) {
                    synchronized (mLock) {
                        mOriginalValues = new ArrayList<String>(objects);
                    }
                }

                if (prefix == null || prefix.length() == 0) {
                    ArrayList<String> list;
                    synchronized (mLock) {
                        list = new ArrayList<String>(mOriginalValues);
                    }
                    results.values = list;
                    results.count = list.size();
                } else {
                    **prefixString = prefix.toString();** // get string to search

                    ArrayList<String> values;
                    synchronized (mLock) {
                        values = new ArrayList<String>(mOriginalValues);
                    }

                    final int count = values.size();
                    final ArrayList<String> newValues = new ArrayList<String>();

                    for (int i = 0; i < count; i++) {
                        final String value = values.get(i);
                        final String valueText = value.toString().toLowerCase();

                        // First match against the whole, non-splitted value
                        if (valueText.startsWith(prefixString)) {
                            newValues.add(value);
                        } else {
                            final String[] words = valueText.split(" ");
                            final int wordCount = words.length;

                            // Start at index 0, in case valueText starts with space(s)
                            for (int k = 0; k < wordCount; k++) {
                                if (words[k].startsWith(prefixString)) {
                                    newValues.add(value);
                                    break;
                                }
                            }
                        }
                    }

                    results.values = newValues;
                    results.count = newValues.size();
                }

                return results;
            }
            @SuppressWarnings("unchecked")
            @Override
            protected void publishResults(CharSequence constraint,  FilterResults results) {
                   objects = (ArrayList<String>) results.values;
                if (results.count > 0) {
                                   notifyDataSetChanged();
                               } else {
                                 notifyDataSetInvalidated();
                              }

            }

        };
    }

Answer 1

This what I use :

• Every occurence is replaced (not only prefix)
• Case and accent are ignored while searching but retained in the result.
• It uses directly SpannableString, which you can use in setText(). I believe it's more efficient than using an intermediate html step.

.

public static CharSequence highlight(String search, String originalText) {
    // ignore case and accents
    // the same thing should have been done for the search text
    String normalizedText = Normalizer.normalize(originalText, Normalizer.Form.NFD).replaceAll("\p{InCombiningDiacriticalMarks}+", "").toLowerCase();

    int start = normalizedText.indexOf(search);
    if (start < 0) {
        // not found, nothing to to
        return originalText;
    } else {
        // highlight each appearance in the original text
        // while searching in normalized text
        Spannable highlighted = new SpannableString(originalText);
        while (start >= 0) {
            int spanStart = Math.min(start, originalText.length());
            int spanEnd = Math.min(start + search.length(), originalText.length());

            highlighted.setSpan(new BackgroundColorSpan(<background_color>), spanStart, spanEnd, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);

            start = normalizedText.indexOf(search, spanEnd);
        }

        return highlighted;
    }
}