getFlightAreaList 报错修改

Backend/sample/src/main/java/com/dji/sample/map/service/impl/FlightAreaServiceImpl.java

@@ -92,7 +92,7 @@ public class FlightAreaServiceImpl extends AbstractFlightAreaService implements
     public List<FlightAreaDTO> getFlightAreaList(String workspaceId) {
         Optional<List<GetMapElementsResponse>> elementsOpt = groupService.getGroupByWorkspaceId(workspaceId,GroupTypeEnum.CUSTOM)
                 .map(group -> workspaceElementService.getAllGroupsByWorkspaceId(workspaceId, group.getId(), null));
-        if (elementsOpt.isEmpty()) {
+        if (elementsOpt.isEmpty() || elementsOpt.get().isEmpty()) {
             return Collections.emptyList();
         }
         List<MapGroupElement> elements = elementsOpt.get().get(0).getElements();