Can't bind JavaFX TextField to ListView value - javafx

Question

I have a JavaFX ListView. When I click on an item in the list, I would like like two...edit controls, a ComboBox and a TextField, to be populated by the appropriate values from the model.
First, my model:
public class Recipient {
private final SimpleStringProperty type = new SimpleStringProperty();
private final SimpleStringProperty address = new SimpleStringProperty();
// property getters
}
In my controller, I have:
public class Controller implements Initializable {
#FXML
private ComboBox type;
#FXML
private TextField address;
#FXML
private ListView<Recipient> recipList;
private final ObservableList<String> types = FXCollections.observableArrayList("SMS", "Email");
private final ObservableList<Recipient> recips = FXCollections.observableArrayList(Recipient.DUMMYDATA);
private final ObjectProperty<Recipient> recipient = new SimpleObjectProperty<>();
#Override
public void initialize(URL url, ResourceBundle rb) {
type.setItems(types);
recipList.setItems(recips);
recipList.setCellFactory((ListView<Recipient> p) -> new ListCell<Recipient>() {
#Override
public void updateItem(Recipient recip, boolean empty) {
super.updateItem(recip, empty);
final int index = p.getItems().indexOf(recip);
if (index > -1) {
setText(String.format("%s - %s", recip.typeProperty().get(), recip.addressProperty().get()));
} else {
setText(null);
}
}
});
recipient.setValue(new Recipient());
recipList.setOnMouseClicked(event -> recipClicked(event));
type.valueProperty().bindBidirectional(recipient.get().typeProperty());
address.textProperty().bindBidirectional(recipient.get().addressProperty());
}
public void recipClicked(MouseEvent event) {
final MultipleSelectionModel<Recipient> get = recipList.selectionModelProperty().get();
final Recipient selectedItem = get.getSelectedItem();
recipient.setValue(selectedItem);
}
}
When I click on the list, the SimpleObjectProperty is updated as expected, but my controls do now show the data. What am I missing?

Answer 1

Your bindings bind to the properties belonging to the current recipient at the time the bindings are made. If the value of recipient changes, then, for example, address.textProperty will still be bound to the addressProperty() of the previous value of recipient, not the new one.
You can use a listener on recipient to bind and unbind the controls:
recipient.addListener((obs, oldRecipient, newRecipient) -> {
if (oldRecipient != null) {
type.valueProperty().unbindBidirectional(oldRecipient.typeProperty());
address.textProperty().unbindBidirectional(oldRecipient.addressProperty());
}
if (newRecipient != null) {
type.valueProperty().bindBidirectional(newRecipient.typeProperty());
address.textProperty().bindBidirectional(newRecipient.addressProperty());
}
});
As an aside, note that you should not use a mouse listener to respond to changes in selection: it will not work, for example, if the user uses the keyboard to change selection in the list view. You can replace recipList.setOnMouseClicked(...) with
recipient.bind(recipList.getSelectionModel().selectedItemProperty());
and remove recipClicked(...) entirely. (In fact, you might not need recipient at all: you can just replace it with recipList.getSelectionModel().selectedItemProperty().)
public class Controller implements Initializable {
#FXML
private ComboBox type;
#FXML
private TextField address;
#FXML
private ListView<Recipient> recipList;
private final ObservableList<String> types = FXCollections.observableArrayList("SMS", "Email");
private final ObservableList<Recipient> recips = FXCollections.observableArrayList(Recipient.DUMMYDATA);
#Override
public void initialize(URL url, ResourceBundle rb) {
type.setItems(types);
recipList.setItems(recips);
recipList.setCellFactory((ListView<Recipient> p) -> new ListCell<Recipient>() {
#Override
public void updateItem(Recipient recip, boolean empty) {
super.updateItem(recip, empty);
if (empty) {
setText(null);
} else {
setText(String.format("%s - %s", recip.typeProperty().get(), recip.addressProperty().get()));
}
}
});
recipList.getSelectionModel().selectedItemProperty().addListener((obs, oldRecipient, newRecipient) -> {
if (oldRecipient != null) {
type.valueProperty().unbindBidirectional(oldRecipient.typeProperty());
address.textProperty().unbindBidirectional(oldRecipient.addressProperty());
}
if (newRecipient != null) {
type.valueProperty().bindBidirectional(newRecipient.typeProperty());
address.textProperty().bindBidirectional(newRecipient.addressProperty());
}
});
}
}