How can I set the unit increment for a scroll pane in JavaFX?

Question

The ScrollBar class in JavaFX contains a property for setting the unit increment, which is what I'm after - however I can't find how to get at this ScrollBar, or set the unit increment some other way from the ScrollPane class! I presume I must be missing something obvious - how do I achieve this?

Answer 1

you can setup a ScrollEventListener to the ScrollPane and thus override the original behavior. This way, for example, I implemented a ScrollPane that scrolls horizontally instead of vertically. This is what the relevant part of my code looks like:

public class Overview extends ScrollPane {

...



  private void setupHorizontalScrolling() {
    this.setOnScroll(new EventHandler<ScrollEvent>() {
      @Override
      public void handle(ScrollEvent scrollEvent) {
        double deltaY = scrollEvent.getDeltaY()*2; // *2 to make the scrolling a bit faster
        double width = Overview.this.getContent().getBoundsInLocal().getWidth();
        double hvalue = Overview.this.getHvalue();
        Overview.this.setHvalue(hvalue + -deltaY/width); // deltaY/width to make the scrolling equally fast regardless of the actual width of the component
      }
    });
  }

...

}

To meet your requirement, you can just change the line where the get/setHvalue is called to get/setVvalue and then you can adjust the scrolling like you want.