Determines the relative position (index in child list) of a node clicked in a JavaFX HBox.

HBoxPositions.java

import javafx.application.Application;
import javafx.event.EventHandler;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.effect.*;
import javafx.scene.image.*;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.*;
import javafx.scene.paint.Color;
import javafx.stage.Stage;

/** Determines the relative position (index in child list) of a node clicked in a HBox */
public class HBoxPositions extends Application {

  private static final String[] ICON_LOCS =
    {
      "http://icons.iconarchive.com/icons/bevel-and-emboss/car/256/car-orange-icon.png",
      "http://icons.iconarchive.com/icons/bevel-and-emboss/car/256/car-purple-icon.png",
      "http://icons.iconarchive.com/icons/bevel-and-emboss/car/256/lorry-icon.png",
      "http://icons.iconarchive.com/icons/bevel-and-emboss/car/256/van-bus-icon.png"
    };
  private Image[] icons = new Image[ICON_LOCS.length];

  @Override public void init() {
    int i = 0;
    for (String loc: ICON_LOCS) {
      icons[i] = new Image(loc);
      i++;
    }
  }

  @Override public void start(final Stage stage) {
    final Label label = new Label();
    label.setStyle("-fx-font-family: 'Comic Sans MS'; -fx-font-size: 20;");

    final HBox images = new HBox(10);
    for (Image icon: icons) {
      final ImageView imageView = new ImageView(icon);
      images.getChildren().add(imageView);

      final DropShadow shadow = new DropShadow();
      shadow.setColor(Color.FORESTGREEN);
      final Glow glow = new Glow();
      glow.setInput(shadow);
      imageView.setOnMouseEntered(new EventHandler<MouseEvent>() {
        @Override public void handle(MouseEvent mouseEvent) {
          imageView.setEffect(glow);
        }
      });
      imageView.setOnMouseExited(new EventHandler<MouseEvent>() {
        @Override
        public void handle(MouseEvent mouseEvent) {
          imageView.setEffect(null);
        }
      });

      imageView.setOnMousePressed(new EventHandler<MouseEvent>() {
        @Override public void handle(MouseEvent mouseEvent) {
          final Object selectedNode = mouseEvent.getSource();
          final int    selectedIdx  = images.getChildren().indexOf(selectedNode);

          label.setText(
              "Selected Vehicle: " + (selectedIdx + 1)
          );
        }
      });
    }

    final VBox layout = new VBox(10);
    layout.setAlignment(Pos.CENTER);
    layout.setStyle("-fx-padding: 10; -fx-background-color: cornsilk;");
    layout.getChildren().addAll(images, label);

    stage.setScene(new Scene(layout));
    stage.show();
  }

  public static void main(String[] args) { launch(args); }
}

Answer to StackOverflow question: Finding the pressed Node's position in a HBox