在JavaFX中将ChoiceBox项设置得太慢

Question

i have a problem with setting item in ChoiceBox , so basicly i must load data from a database i do it in another thread :

final Service<ObservableList<Country>> countryService = new Service<ObservableList<Country>>() {

            @Override
            protected Task<ObservableList<Country>> createTask() {
                return new Task<ObservableList<Country>>() {

                    @Override
                    protected ObservableList<Country> call() throws Exception {
                        Dao<Country, Integer> countriesDao = null;
                        List<Country> result = null;

                        try {
                            countriesDao = DaoManager.createDao(Connection.getNewInstance(), Country.class);
                            System.out.println("getting data");
                            result = countriesDao.queryForAll();
                            System.out.println("got data");
                        } catch (SQLException ex) {
                            Logger.getLogger(ListClientsController.class.getName()).log(Level.SEVERE, null, ex);
                        }

                        return FXCollections.observableArrayList(result);

                    }
                };
            }
        };

        countryService.setOnSucceeded(new EventHandler<WorkerStateEvent>() {

            @Override
            public void handle(WorkerStateEvent event) {
                  // taking a lot of time here like 4-5 second and freeze
                  // the gui(normal because it executed in Javafx Application Thread

                 // but why its take so much time??
                 cbSearchCountry.setItems(countryService.getValue());
            }
        });


        countryService.start();

Normally database access should take a time longer that setting a list to a ChoiceBox, but no here fetching 150 record from my database is instantaneous but settings observable list to my ChoiceBox take about 5 seconds why? because i have too much Node in my current Scene??

Answer 1

仅当您有<10个项目时才使用ChoiceBox，否则请使用ComboBox