Customize the properties of a TreeCell by overriding the updateItem method, allowing you to adjust its appearance based on the value of the TreeItem it contains.
In this example, cells containing values with the prefix "child" are assigned a pseudoclass, while empty cells receive a black background.
TreeView<String> treeView = ...
PseudoClass childPseudoClass = PseudoClass.getPseudoClass("child");
treeView.setCellFactory(tv -> new TreeCell<String>() {
@Override
protected void updateItem(String item, boolean empty) {
super.updateItem(item, empty);
if (empty || item == null) {
// Customize for empty or null-filled cell
pseudoClassStateChanged(childPseudoClass, false);
setText("");
setStyle("-fx-background-color: black;");
} else {
// Customize for filled cell
pseudoClassStateChanged(childPseudoClass, item.startsWith("child"));
setText(item);
setStyle(null);
}
}
});
CSS Stylesheet
.tree-cell:child {
-fx-background-color: red;
}
The updateItem method is triggered by the TreeView whenever the value changes, such as when a new TreeItem is linked to the cell or the value property of a TreeItem is altered.
You can also use the factory to attach listeners to the TreeCell, before it's returned, if you prefer this approach and wish to modify the cell based on the treeItemproperty.
EDIT: Different colors for text require using separate Nodes for each text section.
treeView.setCellFactory(tv -> new TreeCell<Bag>() {
private final Text assignment;
private final Text caption;
private final Node graphic;
{
assignment = new Text();
caption = new Text();
assignment.getStyleClass().add("assignment");
graphic = new HBox(4, assignment, caption);
setGraphic(graphic);
}
@Override
protected void updateItem(Bag item, boolean empty) {
super.updateItem(item, empty);
if (empty || item == null) {
setGraphic(null);
} else {
setGraphic(graphic);
assignment.setText(item.assignment);
caption.setText(item.caption);
caption.getStyleClass().remove("true");
if (item.eval) {
caption.getStyleClass().add("true");
}
}
}
});
To color the text, utilize the -fx-fill property rather than the -fx-text-fill property.