如何设置AutocompleteTextView一次仅执行一个过滤器搜索并设置开始过滤之前的延迟？

Question

I have this question related the AutocompleteTextView. Basically I have implemented a custom adapter with a custom Filter which filters a list of custom objects and all is working fine except that when I type in a fast way in the autocompleteTextView seems like a queue of worker filter threads starts and the typing and filtering itself becomes really slow. How can I set only ONE filter at a time based on the latest input of the user (thus cancel the previous filter thread if it actually runs) and set a small delay before starting the filtering so when the user types fast the autocomplete doesn't slow???

Thanks!

EDIT: I have this custom adapter with a Filter implementation:

public class MunicipalitySearchAdapter extends ArrayAdapter<Municipality> {

private ArrayList<Municipality> municipalities;
private ArrayList<Municipality> allMunicipalities;
private ArrayList<Municipality> suggestedMunicipalities;

private List<Trieable> triableList;

private Trie municipalityTrie;

private int viewResourceId;

@SuppressWarnings("unchecked")
public MunicipalitySearchAdapter(Context context, int viewResourceId, ArrayList<Municipality> municipalities) {
    super(context, viewResourceId, municipalities);
    this.municipalities = municipalities;
    this.allMunicipalities = (ArrayList<Municipality>) this.municipalities.clone();
    this.suggestedMunicipalities = new ArrayList<Municipality>();
    this.viewResourceId = viewResourceId;
    this.triableList = new ArrayList<Trieable>();
    for (Municipality mun : allMunicipalities) {
        triableList.add(mun);
    }
    municipalityTrie = new Trie(triableList, Locale.ITALY);
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    View v = convertView;
    if (v == null) {
        LayoutInflater inflater = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        v = inflater.inflate(this.viewResourceId, null);
    }
    Municipality municipality = municipalities.get(position);
    if (municipality != null) {
        TextView munNameTxtView = (TextView) v.findViewById(R.id.name);
        TextView proSignTxtView = (TextView) v.findViewById(R.id.sign);
        TextView regNameTxtView = (TextView) v.findViewById(R.id.regionName);

        if (munNameTxtView != null) {
            munNameTxtView.setText(municipality.getName());
        }
        if (proSignTxtView != null) {
            proSignTxtView.setText(municipality.getProvinceSign());
        }
        if (regNameTxtView != null) {
            regNameTxtView.setText(municipality.getRegionName());
        }
    }
    return v;
}

@Override 
public Filter getFilter() {
    return municipalityFilter;
}

Filter municipalityFilter = new Filter() {      
    CharSequence filterConstraint;
    @Override
    public String convertResultToString(Object resultValue) {
        String str = ((Municipality) (resultValue)).getName();
        return str;
    }

    @Override
    protected FilterResults performFiltering(CharSequence constraint) {
        FilterResults filterRes = new FilterResults();
        synchronized (filterRes) {
            if (this.filterConstraint == null) {
                this.filterConstraint = constraint;
            }

            if (constraint == null || constraint.length() == 0) {
                filterRes.values = allMunicipalities;
                filterRes.count = allMunicipalities.size();
            }

            else {
                String constraintString = constraint.toString().trim().toLowerCase(Locale.ITALY);
                suggestedMunicipalities.clear();

                List<Integer> wordsIndexesList = municipalityTrie.getWordsIndexes(municipalityTrie.getRootVertex(), constraintString);
                for (int index : wordsIndexesList) {
                    suggestedMunicipalities.add(allMunicipalities.get(index));
                }

                List<Integer> prefixesIndexesList = municipalityTrie.getPrefixesIndexes(municipalityTrie.getRootVertex(), constraintString);
                for (int index : prefixesIndexesList) {
                    suggestedMunicipalities.add(allMunicipalities.get(index));
                }

                filterRes.values = suggestedMunicipalities;
                filterRes.count = suggestedMunicipalities.size();                   
            }
        }

        return filterRes;

    }

    @Override
    protected void publishResults(CharSequence constraint, FilterResults results) {
        if (results != null && results.count > 0) {
            synchronized (results) {
                @SuppressWarnings("unchecked")
                ArrayList<Municipality> filteredMunicipalities = (ArrayList<Municipality>) results.values;
                ArrayList<Municipality> supportMunicipalitiesList = new ArrayList<Municipality>();

                clear();
                for (Municipality mun : filteredMunicipalities) {
                    supportMunicipalitiesList.add(mun);
                }
                Iterator<Municipality> municipalityIterator = supportMunicipalitiesList.iterator();
                while (municipalityIterator.hasNext()) {
                    Municipality municipality = municipalityIterator.next();
                    add(municipality);
                }
                notifyDataSetChanged();
            }
        }           
    }
};
}

How can I make a Loader manage this filter worker thread?

Answer 1

Best approach is to use Loader. On textinput change restart the loader to search for the current text. So if there is a loder with same Id is already running it will be restarted. This will make sure you will get the result of last input . I am using this approach in one of my app in play store.

   getLoaderManager().restartLoader(0, bundle, callback);
 // 0 - I'd
// pass the input text through bundle
// callback - loader callback

Note : you can call restart for the first search itself, it will be created if not exist.

Check this link if your not aware of loader http://developer.android.com/guide/components/loaders.html