Java TilePane .prefTileWidthProperty ()

public final DoubleProperty prefTileWidthProperty()

import javafx.application.Application;
import javafx.geometry.Insets;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.control.CheckBox;
import javafx.scene.layout.HBox;
import javafx.scene.layout.TilePane;
import javafx.stage.Stage;
//ww  w. j  a  v  a 2 s.  co  m
public class Main extends Application {
  public static void main(String[] args) {
    launch(args);
  }

  @Override
  public void start(Stage stage) {
    Scene scene = new Scene(new Group(), 450, 250);

    TilePane tile = new TilePane();
    tile.setHgap(8);
    tile.setPrefColumns(4);
    for (int i = 0; i < 20; i++) {
      tile.getChildren().add(new CheckBox("CheckBox"));
    }
    System.out.println(tile.prefTileWidthProperty());
    HBox hbox = new HBox(10);
    hbox.setPadding(new Insets(20, 0, 0, 20));
    hbox.getChildren().setAll(tile);

    Group root = (Group) scene.getRoot();
    root.getChildren().add(hbox);
    stage.setScene(scene);
    stage.show();
  }
}