如何为AutoCompleteTextView实现HashMap

Question

Good day,

I have a following problem. In my Android application I have a list of entries in XML that contains bus stop name and ID. Those are put in a HashMap as IDs are unique, while stop names are not. The user interface of activity contains an AutoCompleteTextView and Spinner.

My objective is to populate auto-complete view with stop names and then pass the ID of selected stop to the other class that will display bus lines on that stop in spinner (via remote API).

So what the user will do is start typing stop name (eg Awesome Stop) and he will see two entries in auto-complete suggestions. Depending on which one he will select spinner will show different results.

My problem is that I can't figure out how to couple AutoCompleteTextView and HashMap. Auto-complete works well with ArrayAdapter<String> populated via ArrayList<String> but it's not terribly helpful because I can only get stop name back, and it's not very helpful since I actually need ID.

Many thanks for any tip.

Answer 1

OK, after a fair bit of time I figured it out, thanks to the tip from joaquin. It was indeed done by implementing custom adapter. And the HashMap was not very helpful in original goal. Below is the code, if someone stumbles upon a similar challenge.

Activity:

// Members
private long currentStopId;
protected Map<String,String> lineMap;
protected ArrayList<Stop> stopMap;
protected String previousUrl = null;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_add_line);

    // Get the list of stops from resourse XML
    getStopInformation();

    // Enable auto-complete
    stopInput = (AutoCompleteTextView) findViewById(R.id.inputStopName);
    final HashMapAdapter adapter = new HashMapAdapter(this,R.layout.stop_list,stopMap);
    stopInput.setAdapter(adapter);

    // Add listener for auto-complete selection
    stopInput.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        public void onItemClick(AdapterView<?> parent, View view, int position, long rowId) {
            String selection = (String)parent.getItemAtPosition(position);

            // There we get the ID.
            currentStopId = parent.getItemIdAtPosition(position);
        }
    });
}

Adapter implementation:

public class StopAdapter extends BaseAdapter implements Filterable {

private ArrayList<Stop> inputStopList;
private ArrayList<Stop> inputStopListClone;
private LayoutInflater lInflater;

/** Constructor */
public StopAdapter(Context context, int textViewResourceId, ArrayList<Stop> input) {
    lInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    inputStopList = input;
    inputStopListClone = inputStopList;
}

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

@Override
public Object getItem(int i) {
    Stop value = inputStopList.get(i);
    return value.getStopName();
}

@Override
public long getItemId(int i) {
    Stop stop = inputStopList.get(i);
    long value = Long.parseLong(stop.getStopCode());
    return value;
}

@Override
public View getView(int i, View view, ViewGroup viewGroup) {
    View myView = view;

    // R.layout.stop_list created in res/layout
    if(myView == null)
        myView = lInflater.inflate(R.layout.stop_list,viewGroup, false);

    ((TextView) myView.findViewById(R.id.textView)).setText(getItem(i).toString());

    return myView;
}

/** Required by AutoCompleteTextView to filter suggestions. */
@Override
public Filter getFilter() {
    Filter filter = new Filter() {
        @Override
        protected FilterResults performFiltering(CharSequence charSequence) {
            FilterResults filterResults = new FilterResults();

            if(charSequence == null || charSequence.length() == 0) {
                ArrayList<Stop> originalValues = new ArrayList<Stop>(inputStopList);
                filterResults.count = originalValues.size();
                filterResults.values = originalValues;
            }
            else {
                ArrayList<Stop> newValues = new ArrayList<Stop>();

                // Note the clone - original list gets stripped
                for(Stop stop : inputStopListClone)
                {
                    String lowercase = stop.getStopName().toLowerCase();
                    if(lowercase.startsWith(charSequence.toString().toLowerCase()))
                        newValues.add(stop);
                }

                filterResults.count = newValues.size();
                filterResults.values = newValues;
            }
            return filterResults;
        }

        @Override
        protected void publishResults(CharSequence charSequence, FilterResults filterResults) {

            if(filterResults != null && filterResults.count > 0) {
                inputStopList = (ArrayList<Stop>)filterResults.values;
                notifyDataSetChanged();
            }
            else notifyDataSetInvalidated();
        }
    };
    return filter;
}

}

Answer 2

You are using AutoCompleteTextView instead of MultiAutoCompleteTextView .

MultiAutoCompleteTextView is exactly what you need because it works exactly equal as AutoCompleteTextView with the difference that it can show more than one suggestion (if they exist) and lets the user choose only one of them.

Reference Image: http://i.stack.imgur.com/9wMAv.png

For a nice example check out Android Developers: http://developer.android.com/reference/android/widget/MultiAutoCompleteTextView.html