android - Autocomplete textbox highlighting the typed character in the suggestion list

Question

I have been working on AutoCompleteTextView. I was able to get the suggestion and all in the drop down list as we type.

My question is: Can we highlight the typed character in the suggestion drop down list?

Answer 1

I have achieved the functionality. The solution is as follows:

AutoCompleteAdapter.java

public class AutoCompleteAdapter extends ArrayAdapter<String> implements
        Filterable {

    private ArrayList<String> fullList;
    private ArrayList<String> mOriginalValues;
    private ArrayFilter mFilter;
    LayoutInflater inflater;
    String text = "";

    public AutoCompleteAdapter(Context context, int resource,
            int textViewResourceId, List<String> objects) {

        super(context, resource, textViewResourceId, objects);
        fullList = (ArrayList<String>) objects;
        mOriginalValues = new ArrayList<String>(fullList);
        inflater = LayoutInflater.from(context);

    }

    @Override
    public int getCount() {
        return fullList.size();
    }

    @Override
    public String getItem(int position) {
        return fullList.get(position);
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        View view = convertView;
        // tvViewResourceId = (TextView) view.findViewById(android.R.id.text1);
        String item = getItem(position);
        Log.d("item", "" + item);
        if (convertView == null) {
            convertView = view = inflater.inflate(
                    android.R.layout.simple_dropdown_item_1line, null);
        }
        // Lookup view for data population
        TextView myTv = (TextView) convertView.findViewById(android.R.id.text1);
        myTv.setText(highlight(text, item));
        return view;
    }

    @Override
    public Filter getFilter() {
        if (mFilter == null) {
            mFilter = new ArrayFilter();
        }
        return mFilter;
    }

    private class ArrayFilter extends Filter {
        private Object lock;

        @Override
        protected FilterResults performFiltering(CharSequence prefix) {
            FilterResults results = new FilterResults();
            if (prefix != null) {
                text = prefix.toString();
            }
            if (mOriginalValues == null) {
                synchronized (lock) {
                    mOriginalValues = new ArrayList<String>(fullList);
                }
            }

            if (prefix == null || prefix.length() == 0) {
                synchronized (lock) {
                    ArrayList<String> list = new ArrayList<String>(
                            mOriginalValues);
                    results.values = list;
                    results.count = list.size();
                }
            } else {
                final String prefixString = prefix.toString().toLowerCase();
                ArrayList<String> values = mOriginalValues;
                int count = values.size();

                ArrayList<String> newValues = new ArrayList<String>(count);

                for (int i = 0; i < count; i++) {
                    String item = values.get(i);
                    if (item.toLowerCase().contains(prefixString)) {
                        newValues.add(item);
                    }

                }

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

            return results;
        }

        @SuppressWarnings("unchecked")
        @Override
        protected void publishResults(CharSequence constraint,
                FilterResults results) {

            if (results.values != null) {
                fullList = (ArrayList<String>) results.values;
            } else {
                fullList = new ArrayList<String>();
            }
            if (results.count > 0) {
                notifyDataSetChanged();
            } else {
                notifyDataSetInvalidated();
            }
        }

    }

    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(Locale.ENGLISH);

        int start = normalizedText.indexOf(search.toLowerCase(Locale.ENGLISH));
        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 ForegroundColorSpan(Color.BLUE),
                        spanStart, spanEnd, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);

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

            return highlighted;
        }
    }
}

MainActivity.java

public class MainActivity extends Activity {

    String[] languages = { "C", "C++", "Java", "C#", "PHP", "JavaScript",
            "jQuery", "AJAX", "JSON" };

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);


        List<String> wordList = new ArrayList<String>(); 
        Collections.addAll(wordList, languages); 
        AutoCompleteAdapter adapter = new AutoCompleteAdapter(this,
                android.R.layout.simple_dropdown_item_1line,
                android.R.id.text1,wordList);
        AutoCompleteTextView acTextView = (AutoCompleteTextView) findViewById(R.id.languages);
        acTextView.setThreshold(1);
        acTextView.setAdapter(adapter);
    }
}

Working like charm!

Enjoy!