No errors but the if statement isn't functioning how it's supposed to. I'm also unsure where the if statement should be located

Question

If item in the first combo box is selected then I want to be able to populate the second combo box with the associated items

   ChoiceBox cbDestination = new ChoiceBox(FXCollections.observableArrayList(
             "Krakow",
             "Ios",
             "Amsterdam"));

   ChoiceBox cbAccommodation = new ChoiceBox();

  if (cbDestination.getValue().ToString() == "Krakow" ) {
          cbAccommodation.setItems(FXCollections.observableArrayList(
        "Your Place",
        "Flames"));



  } else if (cbDestination.getValue().ToString() == "Ios" ) {
          cbAccommodation.setItems(FXCollections.observableArrayList(
        "Homers",
        "Marias"));
  }   else  {
          cbAccommodation.setItems(FXCollections.observableArrayList(
        "Old Quarter",
        "St.Christophers Inn"));

  }

Note: You should take a look at [How do I compare strings in Java?](https://stackoverflow.com/q/513832/8097737). — , Apr 11 '18 at 08:18

score 1 · Answer 1 · answered Apr 11 '18 at 08:19

You need to do this when the value changes instead of using the value initially assigned (null).

Furthermore you should not compare strings using == and the call to toString can be avoided by using a type parameter for ChoiceBox.

Also it's preferable to use a Map<String, ObservableList<String>> instead of doing a if/else if or using a switch:

ChoiceBox<String> cbDestination = new ChoiceBox<>(FXCollections.observableArrayList(
        "Krakow",
        "Ios",
        "Amsterdam"));

ChoiceBox<String> cbAccommodation = new ChoiceBox<>();
Map<String, ObservableList<String>> values = new HashMap<>();
values.put("Krakow", FXCollections.observableArrayList("Your Place", "Flames"));
values.put("Ios", FXCollections.observableArrayList("Homers", "Marias"));
values.put("Amsterdam", FXCollections.observableArrayList("Old Quarter", "St.Christophers Inn"));

cbDestination.valueProperty().addListener((o, oldVal, newVal) -> {
    ObservableList<String> items = values.get(newVal);
    cbAccommodation.setItems(items == null ? FXCollections.emptyObservableList() : items);
});

score 0 · Accepted Answer · answered Apr 11 '18 at 08:13

Since you want to do something when the selected item in the ChoiceBox is change you need to add a ChangeListener:

cbDestination.getSelectionModel().selectedItemProperty().addListener((observable, oldValue, newValue) -> {
        if ("Krakow".equals(newValue)) {
            cbAccommodation.setItems(FXCollections.observableArrayList("Your Place", "Flames"));
        } else if ("Ios".equals(newValue)) {
            cbAccommodation.setItems(FXCollections.observableArrayList("Homers", "Marias"));
        } else {
            cbAccommodation.setItems(FXCollections.observableArrayList("Old Quarter", "St.Christophers Inn"));
        }
    }
);

Thank you so much, really helpful! – Ciara Cooke Apr 11 '18 at 08:20 — Ciara Cooke, Apr 11 '18 at 08:20

No errors but the if statement isn't functioning how it's supposed to. I'm also unsure where the if statement should be located

2 Answers2