Suggest addresses in tooltip in GWT / Java

Question

I want to define SuggestBox , which behaves like a search string in Google Maps : when you start typing, real addresses, starting with typed letters.

I think I need to use the Geocoder.getLocations (String address, LocationCallback callback) method, but I have no idea how to relate this to the oracle, which is needed in the tooltip to present my suggestions.

Could you give me ideas on how to associate the getLocations method with SuggestOracle ?

Answer 1

I solved this by running a subclass of SuggestBox that has its SuggestOracle . AddressOracle used as a wrapper for the Google Maps service, for which the Geocoder class in the Google Maps API for GWT offers abstractions.

So here is my solution:

First we will implement a widget for a proposal with offers of Google Maps

 public class GoogleMapsSuggestBox extends SuggestBox { public GoogleMapsSuggestBox() { super(new AddressOracle()); } } 

Then we implement the sentence, which wraps the abstractions of the Geocoder asynchronous method:

 class AddressOracle extends SuggestOracle { // this instance is needed, to call the getLocations-Service private final Geocoder geocoder; public AddressOracle() { geocoder = new Geocoder(); } @Override public void requestSuggestions(final Request request, final Callback callback) { // this is the string, the user has typed so far String addressQuery = request.getQuery(); // look up for suggestions, only if at least 2 letters have been typed if (addressQuery.length() > 2) { geocoder.getLocations(addressQuery, new LocationCallback() { @Override public void onFailure(int statusCode) { // do nothing } @Override public void onSuccess(JsArray<Placemark> places) { // create an oracle response from the places, found by the // getLocations-Service Collection<Suggestion> result = new LinkedList<Suggestion>(); for (int i = 0; i < places.length(); i++) { String address = places.get(i).getAddress(); AddressSuggestion newSuggestion = new AddressSuggestion( address); result.add(newSuggestion); } Response response = new Response(result); callback.onSuggestionsReady(request, response); } }); } else { Response response = new Response( Collections.<Suggestion> emptyList()); callback.onSuggestionsReady(request, response); } } } 

And this is a special class for oracle sentences that simply represent a string with a given address.

 class AddressSuggestion implements SuggestOracle.Suggestion, Serializable { private static final long serialVersionUID = 1L; String address; public AddressSuggestion(String address) { this.address = address; } @Override public String getDisplayString() { return this.address; } @Override public String getReplacementString() { return this.address; } } 

Now you can bind the new widget to your web page by writing the following line in the onModuleLoad() method of your EntryPoint -class:

 RootPanel.get("hm-map").add(new GoogleMapsSuggestBox());