问存储在类扩展应用程序中的数据返回null

EN

public class CharacterSheet extends Application {
private HashMap<PointOfInterest, Date> coolDowns = new HashMap<>();

    public HashMap GetAllCoolDowns() { return coolDowns; } //dev only?
    public Date GetCoolDown(PointOfInterest poi) {return coolDowns.get(poi);}
    public Date PutCoolDown(PointOfInterest poi, Date date) {return coolDowns.put(poi, date);}}

    @Override
public void onPoiClick(final PointOfInterest poi) {

    //POI Cool Down
    Date currentTime = Calendar.getInstance().getTime();
    Date lastTime = ((CharacterSheet) this.getApplication()).GetCoolDown(poi);//this ONLY returns null??

    if (lastTime != null){
        int timeDiff = currentTime.compareTo(lastTime);
        makeToast("Time Since last visit: " + timeDiff );
    } else { makeToast("First");
        }

    ((CharacterSheet) this.getApplication()).PutCoolDown(poi, currentTime);
    makeToast("This?" + ((CharacterSheet) this.getApplication()).GetCoolDown(poi));}

        PlacesClient placesClient = Places.createClient(this);
    String placeId = poi.placeId;
    List<Place.Field> placeFields = Arrays.asList(Place.Field.ID, Place.Field.TYPES);
    FetchPlaceRequest request = FetchPlaceRequest.newInstance(placeId, placeFields);

    placesClient.fetchPlace(request).addOnSuccessListener(new OnSuccessListener<FetchPlaceResponse>() {
        @Override
        public void onSuccess(FetchPlaceResponse fetchPlaceResponse) {
            Place place = fetchPlaceResponse.getPlace();
            PlaceDataHolder holder = new PlaceDataHolder(place);
            String placeName = poi.name;
            makeLootFragment(holder,placeName);