import com.sun.javafx.application.PlatformImpl;
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.TreeItem;
import javafx.scene.control.TreeView;
import javafx.stage.Stage;

import java.util.Timer;
import java.util.TimerTask;

/**
 * @author Alexander Gulko
 */
public class TestTreeView3 extends TreeView<String> {
    private TreeItem<String> root = new TreeItem<String>("root");
    private static int nodesCount = 0;

    public TestTreeView3() {
        setRoot(root);
        setShowRoot(true);
        root.getChildren().add(createChild());

        new Timer().schedule(new TimerTask() {
                                 @Override
                                 public void run() {
                                     PlatformImpl.runLater(new Runnable() {
                                         @Override
                                         public void run() {
                                             root.setExpanded(!root.isExpanded());
                                             if (!root.isExpanded()) {
                                                 root.getChildren().clear();
                                                 root.getChildren().add(createChild());
                                                 System.out.println(nodesCount);
                                             }
                                         }
                                     });
                                 }
                             }, 100, 200);
    }

    private TreeItem<String> createChild() {
        return new TreeItem<String>(String.valueOf(nodesCount++));
    }

    public static class TestTreeApp3 extends Application {
        @Override
        public void start(final Stage stage) throws Exception {
            stage.setResizable(true);
            stage.setTitle("Tree view");
            Scene scene = new Scene(new TestTreeView3(), 400, 600);
            stage.setScene(scene);
            stage.setVisible(true);
        }

        public static void main(final String[] args) {
            try {
                Application.launch(TestTreeApp3.class, args);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }
}