Using filteredList in an editable ListView - javafx

Question

I'm using a FilteredList for my ListView to enable searching. The problem is that FilteredList does not allow mutating the data in any way, it only responds to changes in underlying ObservableList.
Also, it is declared final, so I can't simply extend it to forward the edit requests to the source.
So, how can I use it in an Editable ListView?
Here is the code to reproduce the problem
public class Main extends Application {
public static void main(String[] args) {
launch(args);
}
#Override
public void start(Stage primaryStage) {
//problematic code
var observableList = FXCollections.observableArrayList("name", "name 2", "name 3");
FilteredList<String> filteredList = new FilteredList<>(observableList);
var list = new ListView<>(filteredList);
list.setEditable(true);
list.setCellFactory(TextFieldListCell.forListView());
//boilerplate code
VBox wrapper = new VBox(list);
primaryStage.setScene(new Scene(wrapper));
primaryStage.show();
}
}
Edit: added an minimal reproducible example

Answer 1

The problem - as you noticed - is that none of the concrete implementations of TransformationList (Sorted/FilteredList) is modifiable. So the default commit handler fails (with UnsupportedOperationException) while trying to set the newValue:
private EventHandler<ListView.EditEvent<T>> DEFAULT_EDIT_COMMIT_HANDLER = t -> {
int index = t.getIndex();
List<T> list = getItems();
if (index < 0 || index >= list.size()) return;
list.set(index, t.getNewValue());
};
The way out is a custom commit handler. Its implementation depends on context, it can
set a new item in the underlying source list
modify a property of the item
Code snippet for setting an item:
// monolithic items
ObservableList<String> data = FXCollections.observableArrayList("afirst", "abString", "other");
FilteredList<String> filteredData = new FilteredList<>(data);
filteredData.setPredicate(text -> text.contains("a"));
// set up an editable listView
ListView<String> list = new ListView<>(filteredData);
list.setEditable(true);
list.setCellFactory(TextFieldListCell.forListView());
// commitHandler resetting the underlying data element
list.setOnEditCommit(v -> {
ObservableList<String> items = list.getItems();
int index = v.getIndex();
if (items instanceof TransformationList<?, ?>) {
TransformationList transformed = (TransformationList) items;
items = transformed.getSource();
index = transformed.getSourceIndex(index);
}
items.set(index, v.getNewValue());
});
Code snippet for changing a property of an item:
// items with properties
ObservableList<MenuItem> data = FXCollections.observableArrayList(
new MenuItem("afirst"), new MenuItem("abString"), new MenuItem("other"));
FilteredList<MenuItem> filteredData = new FilteredList<>(data);
// filter on text property
filteredData.setPredicate(menuItem -> menuItem.getText().contains("a"));
// set up an editable listView
ListView<MenuItem> list = new ListView<>(filteredData);
list.setEditable(true);
// converter for use in TextFieldListCell
StringConverter<MenuItem> converter = new StringConverter<>() {
#Override
public String toString(MenuItem menuItem) {
return menuItem != null ? menuItem.getText() : null;
}
#Override
public MenuItem fromString(String text) {
return new MenuItem(text);
}
};
list.setCellFactory(TextFieldListCell.forListView(converter));
// commitHandler changing a property of the item
list.setOnEditCommit(v -> {
ObservableList<MenuItem> items = list.getItems();
MenuItem column = items.get(v.getIndex());
MenuItem standIn = v.getNewValue();
column.setText(standIn.getText());
});