android - AutoCompleteTextView 在适配器更改时隐藏和显示下拉列表

Question

我有一个 AutoCompleteTextView，它从带有 AsyncTask 的 API 获取建议。在 onPostExecute 中，我创建了一个新适配器，将其设置为 AutoCompleteTextView 并将数据集更改通知适配器。

我在 TextWatcher 中执行 AsyncTask。

除了每次更改适配器时都会关闭和显示下拉菜单外，一切正常。

如何在数据发生变化时保持下拉菜单打开？

searchText.addTextChangedListener(new TextWatcher() {
        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) {
            // TODO Auto-generated method stub

        }

        @Override
        public void beforeTextChanged(CharSequence s, int start, int count,
                int after) {
            // TODO Auto-generated method stub

        }

        @Override
        public void afterTextChanged(Editable s) {
            if (s.length() > 0) {
                searchPlacesTask.cancel(true);
                searchPlacesTask = new SearchPlacesTask();
                searchPlacesTask.execute(s.toString().replace(" ", "-"));
            } else {
                searchPlacesTask.cancel(true);
                searchPlacesTask = new SearchPlacesTask();
                searchPlacesTask.execute();
            }
        }
    });



private class SearchPlacesTask extends AsyncTask<String, Void, PlacesAPIResult> {

    @Override
    protected PlacesAPIResult doInBackground(String... params) {
        PlacesAPIResult result = new PlacesAPIResult();

        if (params.length > 0) {
            places = PlacesAPIRestMethod.placeAutocomplete(params[0], currentLocation.getLatitude(), currentLocation.getLongitude(), 
                    500, null, result);
        } else {
            places = PlacesAPIRestMethod.placeSearch(currentLocation.getLatitude(), currentLocation.getLongitude(), 0, true, result);
        }

        return result;
    }

    @Override
    protected void onPostExecute(PlacesAPIResult result) {
        if (result.getResult() == PlacesAPIResult.OK) {
            adapter = new PlaceAdapter(ChooseLocationActivity.this, R.layout.locationrow, places);
            searchText.setAdapter(adapter);
            adapter.notifyDataSetChanged();
        }
    }
}

Answer 1

在适配器中实现 Filterable，并添加此代码。

public class ListAdapter extends ArrayAdapter<String> implements Filterable{


    private List<String> listResult;

    ...
    @Override
    public Filter getFilter() {
        Filter filter = new Filter() {

            @Override
            protected FilterResults performFiltering(CharSequence constraint) {
                FilterResults filterResults = new FilterResults();
                if (constraint != null) {
                    // Assign the data to the FilterResults
                    filterResults.values = listResult;
                    filterResults.count = listResult.size();
                    }
                return filterResults;
                }

            @Override
            protected void publishResults(CharSequence constraint, FilterResults results) {
                if (results != null && results.count > 0) {
                    notifyDataSetChanged();
                }
                else {
                    notifyDataSetInvalidated();
                }
            }};
        return filter;
    }
}