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

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.

Technically, you should be able to get to it using the .lookup("scrollbar") method after the skin is initialized (if the scrollbar is visible). I don't like that answer though.

I don't think you're missing anything according to this bug ticket:

• How to access to ScrollBar component in ScrollPane control ?
  https://bugs.openjdk.java.net/browse/JDK-8091864

I'd encourage you to jump on that, present your use case, vote, and see if you can get some sort of response in the future.

What I ended up using is:

  @FXML
  private ScrollPane scrollPane;

  @FXML
  public void initialize() {
    Platform.runLater(() -> setFasterScroller(scrollPane));
  }

  private static void setFasterScroller(ScrollPane scrollPane) {
    ScrollBar verticalScrollbar = (ScrollBar) scrollPane.lookup(".scroll-bar:vertical");
    double defaultUnitIncrement = verticalScrollbar.getUnitIncrement();
    verticalScrollbar.setUnitIncrement(defaultUnitIncrement * 3);
  }

This one modifies the speed of the vertical scroller, what you would want to do more often, but it could be changed to .scrollbar:horizontal as well. 3 is used as modifier to accelerate the movement.