JavaFX - 如何创建Transition动画

import javafx.animation.Animation;
import javafx.animation.Transition;
import javafx.application.Application;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.layout.VBox;
import javafx.scene.paint.Color;
import javafx.scene.shape.Rectangle;
import javafx.scene.text.Text;
import javafx.stage.Stage;
import javafx.util.Duration;

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());
    stage.setTitle("Sample");
    stage.setWidth(300);
    stage.setHeight(190);

    VBox vbox = new VBox();
    vbox.setLayoutX(20);
    vbox.setLayoutY(20);
    

    final String content = "Lorem ipsum";
    final Text text = new Text(10, 20, "");
    
    final Animation animation = new Transition() {
        {
            setCycleDuration(Duration.millis(2000));
        }
        protected void interpolate(double frac) {
            final int length = content.length();
            final int n = Math.round(length * (float) frac);
            text.setText(content.substring(0, n));
        }
    
    };
    animation.play();

    vbox.getChildren().add(text);
    vbox.setSpacing(10);
    ((Group) scene.getRoot()).getChildren().add(vbox);

    stage.setScene(scene);
    stage.show();
  }
}