Which CSS selector is used when a DragOver event is detected? - javafx

Question

I am creating a custom RowFactory for my TableView to accept drag-and-drop files. I want to update the style of the specific Row when an acceptable DragOver event is detected.
Using :hover obviously won't work because that would apply even if the user is not dragging anything.
The end goal is simply to make it visually clear which row the user is about to drop the items onto.
Is there a selector I can use in my stylesheet to handle this? I could not find anything in the JavaFX CSS Reference Guide.
I can currently work around this by defining my own StyleClass and adding it in the setOnDragOver() method:
setOnDragOver(event -> {
// Determine if the dragged items are files
if (!this.isEmpty() && event.getDragboard().hasFiles()) {
event.acceptTransferModes(TransferMode.LINK);
this.getStyleClass().add("dragging");
}
});
However, attempting to remove the class when exiting does not seem to work:
setOnDragExited(event -> this.getStyleClass().remove("dragging"));
Edit: I should also clarify that each row may have other styles applied to them (based on several factors) and would want to ADD a style to the row when being dragged over, not replace all the rest)

Answer 1

As mentioned by #kleopatra, working with custom PseudoClass can work for you.
/**
* Interface to keep all custom pseudo classes.
*/
public interface Styles{
/** Dragged pseudo class. */
public static final PseudoClass DRAGGED_PSEUDOCLASS = PseudoClass.getPseudoClass("dragged");
}
In your code:
setOnDragOver(event -> {
if (!this.isEmpty() && event.getDragboard().hasFiles()) {
event.acceptTransferModes(TransferMode.LINK);
this.pseudoClassStateChanged(Styles.DRAGGED_PSEUDOCLASS,true);
}
});
setOnDragExited(event -> this.pseudoClassStateChanged(Styles.DRAGGED_PSEUDOCLASS,false));
In CSS:
.table-row-cell:dragged{
-fx-background-color:$custom-color;
}