Question

I’m working with Flex 4 invoking webservices from JVM 1.6

I’m trying to make asynchronous calls to java to populate three comboboxes that will display country, states and cities, these three are related (master-slave relationship) but sometimes the calls are not met, or they are not completed, and I think this is because they are asynchronous, how can I be sure that I’m making the call to fill the next combobox when the master combobox (country) is filled?

protected function comboCountry_changeHandler(idCombo:String):void
{

            selectedComboCountry= idCombo;
            var countryId:String; 
            if(selectedComboCountry == comboCountry.id){
                countryId = String(comboCountry.selectedItem.countryId);                
            }else if(selectedCombocountry == combocountrySuc.id){
                countryId = String(comboCountrySuc.selectedItem.countryId);
            }



            obtainStatesResult.token = wsfacturas.obtainStates(countryId);


        }

protected function obtainStatesResult_resultHandler(event:ResultEvent):void
{
var StateListVo:ArrayCollection = obtainStatesResult.token.result as ArrayCollection;

            if(selectedComboCountry == "comboCountrySuc"){

                StateListsSuc.removeAll();
                CityListsSuc.removeAll();
                for (var d:int = 0; d < StateListVo.length; d++){
                    var estSuc:State = StateListVo[d];
                    StateListsSuc.addItem(estSuc);                                          
                }       

                comboStateSuc.dataProvider = StateListsSuc;
            }
            else if(selectedCombocountry == "combocountry"){
                StateListsEmp.removeAll();
                CityListsEmp.removeAll();
                for (var i:int = 0; i < StateListVo.length; i++){
                    var estEmp:State = StateListVo[i];
                    StateListsEmp.addItem(estEmp);      
                }                   
                comboState.dataProvider = StateListsEmp;
            } else {

                for (var f:int = 0; f < StateListVo.length; f++){
                    var est:State = StateListVo[f];
                    StateListsSuc.addItem(est); 
                    StateListsEmp.addItem(est); 
                }                           
                comboState.dataProvider = StateListsEmp;
                comboStateSuc.dataProvider = StateListsSuc;

            }
        } 

Answer 1

Wouldn’t it mean that you probably need to load the country and wait for change event on the country combobox to update state and so on? If you do that, you dont have to worry about asynchronicity of your requests? Otherwise, you might be able to use DataProviders and they might provide Event:Complete..
I am not sure though, I definitely am not an expert.. 🙂