Question

我创建了FiltersQueryAdapter作为mainAdapter，它已传递给setupPhotoFilters方法，其中mainadapter被辅助到setAdapter。有可能因为parseGeoPointfromLocation不在FiltersQueryApdapter的范围内，它返回的null是我在这种情况下做的云吗？

  /*
  * Helper method to get the Parse GEO point representation of a location
  */
    public ParseGeoPoint geoPointFromLocation(Location loc) {
        return new ParseGeoPoint(loc.getLatitude(), loc.getLongitude());
    }


    FiltersQueryAdapter mainAdapter = new FiltersQueryAdapter(this, PhotoFiltersAdapter.class
            , new ParseRecyclerQueryAdapter.QueryFactory() {
        public ParseQuery create() {
            Location myLoc = (currentLocation == null) ? lastLocation : currentLocation;
            ParseQuery query = ParseQuery.getQuery("PlaceFilters");
            //query.include("user");
            query.orderByAscending("GeoArea");
            query.whereWithinKilometers("GeoArea", geoPointFromLocation(myLoc), radius);
            query.setLimit(6);
            return query;
        }
    });


    private void setupPhotoFilters() {
        rvFilters.setHasFixedSize(true);
        rvFilters.setAdapter(mainAdapter);
        rvFilters.setLayoutManager(new LinearLayoutManager(this, LinearLayoutManager.HORIZONTAL, false));
    }

Answer 1

您假设此行始终返回非空值：

currentBestLocation = locationManager
    .getLastKnownLocation(LocationManager.NETWORK_PROVIDER);

javadoc表示它可以为null，因此您应该在使用它之前检查它。您通过getCurrentLocation（）传播该值，因此请在那里进行检查。

double getLatitude（）上的NullPointException

1 个答案: