如何在显示虚拟键盘之前将其放在底部居中- javafx

import javafx.application.Application;
import javafx.geometry.Bounds;
import javafx.scene.Scene;
import javafx.scene.control.TextField;
import javafx.scene.layout.VBox;
import javafx.scene.paint.Color;
import javafx.scene.shape.Rectangle;
import javafx.stage.Popup;
import javafx.stage.Stage;

public class VirtualKeyboardExample extends Application {

    @Override
    public void start(Stage primaryStage) {
        TextField textField = new TextField();
        VBox container = new VBox(textField);
        container.setStyle("-fx-padding: 10px;");
        
        Popup popup = new Popup();
        popup.getContent().add(container);
        popup.setAutoHide(true);
        
        textField.setOnMouseClicked(event -> {
            Bounds bounds = textField.localToScreen(textField.getBoundsInLocal());
            popup.show(textField, bounds.getMinX(), bounds.getMaxY());
        });
        
        Rectangle background = new Rectangle(400, 400, Color.LIGHTGRAY);
        background.setOnMouseClicked(event -> popup.hide());
        
        VBox root = new VBox(background);
        Scene scene = new Scene(root, 400, 400);
        
        primaryStage.setScene(scene);
        primaryStage.show();
    }

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