How Can I Display Custom Object Properties in a JavaFX ListView?

How to Populate a ListView in JavaFX Using Custom Objects

The challenge lies in populating a ListView with custom objects instead of strings. Using an observableArrayList of Word objects, where each Word has a wordString and definition, we want the ListView to display the wordString instead of the entire Word object.

Custom Solution

One approach involves using a cell factory to retrieve the wordString from the Word object for each cell. Here's the updated code snippet:

<code class="java">listViewOfWords.setCellFactory(param -> new ListCell<Word>() {
    @Override
    protected void updateItem(Word item, boolean empty) {
        super.updateItem(item, empty);

        if (empty || item == null || item.getWord() == null) {
            setText(null);
        } else {
            setText(item.getWord());
        }
    }
});</code>

Optimized Implementations

1. Avoid Overriding toString for UI Presentation

Rather than overriding toString for UI presentation, consider using a cell factory to extract the appropriate data for UI representation. This keeps the UI presentation logic separate from the object's textual representation.

2. Customization of Cells Using Graphic Nodes

Cell factories allow for more flexible customization, including adding graphic nodes to cells. Here's an example:

<code class="java">public static class WordListCell extends ListCell<Word> {
    private final Label title = new Label();
    private final Label detail = new Label();
    private final VBox layout = new VBox(title, detail);

    public WordListCell() {
        super();
        title.setStyle("-fx-font-size: 20px;");
    }

    @Override
    protected void updateItem(Word item, boolean empty) {
        super.updateItem(item, empty);

        setText(null);

        if (empty || item == null || item.getWord() == null) {
            title.setText(null);
            detail.setText(null);
            setGraphic(null);
        } else {
            title.setText(item.getWord());
            detail.setText(
                    item.getDefinition() != null
                            ? item.getDefinition()
                            : "Undefined"
            );
            setGraphic(layout);
        }
    }
}</code>

3. Immutable Objects and Observable Properties

To prevent unintended object modifications, it's recommended to use immutable Word objects or objects with observable properties for field updates. This allows the UI to respond to property changes.

4. Dynamic Updates

Changes to the underlying observable list items (e.g., adding, removing) will automatically trigger updates in the view. To respond to property changes within objects, you'll need to implement listener logic in the cell factory or use an extractor. An extractor helps notify of changes to observable properties.

Example with Extractor

<code class="java">ObservableList<Word> wordsList = FXCollections.observableArrayList(word ->
        new Observable[] {
                word.wordProperty(),
                word.definitionProperty()
        }
);</code>

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