JavaFX TreeTableView图像伪像

Question

I'd like to add images to each node in a TreeTableView. In order to do this, i wrote (as per some pages found with Google) the following:

Call to update the view in the views controller

public void refreshView() {
    final List<TreeItem<IUnit>> treeItems = new ArrayList();
    final Collection<IUnit> onRootLevel = source.getUnitsOnRootLevel();
    for (final IUnit unit : onRootLevel) {
        treeItems.add(new MyTreeItem(unit));
    }
    root.getChildren().clear();
    root.getChildren().addAll(treeItems);
}

Each item is wrapped

public class MyTreeItem extends TreeItem<IUnit> {
    private final IUnit unit;
    public MyTreeItem(final IUnit unit) {
        super(unit, new LevelImage(unit.getLevel().getIcon()).getImage());
        this.unit = unit;
    }
}

Each item gets the image converted from a BufferedImage

public class LevelImage {
    private ImageView imageView;
    public LevelImage(final BufferedImage image) {
        imageView = new ImageView();
        imageView.setFitHeight(16);
        imageView.setFitWidth(16);
        imageView.setVisible(true);
        imageView.setImage(SwingFXUtils.toFXImage(image, null));
    }
    public ImageView getImage() {
        return this.imageView;
    }
}

In principle, this works fine. Unfortunately when I expand or close the nodes, or refresh the whole table then this leaves artifacts of the images behind or images are not drawn at all anymore. Has anybody an Idea whats a possible reason for this might be. I am Using JavaFX as of Java 10.0.1

Answer 1

@Itai: Thanks! But this is only half the answer, it seems. The problem is also with this:

public MyTreeItem(final IUnit unit) {
    super(unit, >> new LevelImage(unit.getLevel().getIcon()).getImage())  <<;
    this.unit = unit;
}

I cannot set the image here, but have to do it in the CellFactory instead. Otherwise, this does not work. So the correct code here would be

public MyTreeItem(final IUnit unit) {
    super(unit);
    this.unit = unit;
}

And have the magic done in the factory, which means, that the first column cannot be just a string anymore, but needs to be the object itself to also get the icon.

Anyway, what throw me of course yesterday, was that the TreeTableCell as a private 'updateItem' method with just and 'integer' as parameter. Seems my frustration level yesterday got to high and i missed that detail (the parameters). I really thought that the TreeTableCell works differently then all others objects for whatever the reason.