Colorize Sub-item, sub-sub-item, sub-sub-sub-item of TreeView

Question

I'm making a program that shows a TreeViews of Strings. When I make a TreeView, is there any way to colorize the strings itens based in the level of the item directly in the CSS?

treeView.getStylesheets().add("style.css");

.tree-cell:sub-tree-item {
    -fx-text-fill: red;
}

.tree-cell:sub-tree-item:sub-tree-item { /*Does exists something similar of this?? */
    -fx-background-color: green ;
}
...

or I have to make Labels

        TreeItem treeNode1 = new TreeItem("");
        Label lteste11=new Label("myLevelIs1");
        lteste11.setTextFill(Color.RED);
        treeNode1.setGraphic(lteste11);

        TreeItem treeNode2 = new TreeItem("");  
        Label lteste22=new Label("myLevelIs2");
        lteste22.setTextFill(Color.GREEN);
        treeNode2.setGraphic(lteste22);
        
        TreeItem treeNodeROOT = new TreeItem(); 
        treeNodeROOT.getChildren().addAll(treeNode1, treeNode2);
        treeView.setRoot(treeNodeROOT);

? Is there other way?

Answer 1

You can use a custom cell factory to add style classes based on the depth:

TreeView<String> tree = ... ;

tree.setCellFactory(tv -> new TreeCell<>() {
    @Override
    protected void updateItem(String item, boolean empty) {
        super.updateItem(item, empty) ;
        getStyleClass().removeIf(s -> s.startsWith("depth"));
        if (empty || item == null) {
            setText("");
        } else {
            int depth = 0 ;
            for (TreeItem<String> i = getTreeItem().getParent() ; i != null ; i = i.getParent()) {
                depth++ ;
            }
            getStyleClass().add("depth"+depth);
            setText(item);
        } 
    }
});

Then in your stylesheet just do, e.g.:

.tree-cell.depth1 {
    -fx-text-fill: red ;
}
.tree-cell.depth2 {
    -fx-background-color: green ;
}

for as many depths as you want to support.