如何在javafx中创建跨多个窗口的“更改背景颜色选项”

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.ColorPicker;
import javafx.scene.layout.StackPane;
import javafx.scene.paint.Color;
import javafx.stage.Stage;

public class Main extends Application {
    private Stage primaryStage;
    private ColorPicker colorPicker;

    @Override
    public void start(Stage primaryStage) {
        this.primaryStage = primaryStage;
        
        // 创建主窗口
        StackPane mainPane = new StackPane();
        Scene mainScene = new Scene(mainPane, 400, 300);
        primaryStage.setScene(mainScene);
        primaryStage.setTitle("Change Background Color");
        
        // 添加按钮到主窗口
        Button openColorWindowButton = new Button("Open Color Window");
        openColorWindowButton.setOnAction(e -> openColorWindow());
        mainPane.getChildren().add(openColorWindowButton);
        
        // 创建颜色选择器
        colorPicker = new ColorPicker();
        
        // 创建颜色窗口
        Stage colorStage = new Stage();
        StackPane colorPane = new StackPane();
        Scene colorScene = new Scene(colorPane, 300, 200);
        colorStage.setScene(colorScene);
        colorStage.setTitle("Color Window");
        
        // 添加颜色选择器到颜色窗口
        colorPane.getChildren().add(colorPicker);
        
        // 当颜色选择器的值改变时，将颜色应用到主窗口的背景上
        colorPicker.setOnAction(e -> {
            Color selectedColor = colorPicker.getValue();
            mainPane.setStyle("-fx-background-color: " + toRGBCode(selectedColor) + ";");
        });
        
        primaryStage.show();
    }
    
    private void openColorWindow() {
        Stage colorStage = new Stage();
        colorStage.initOwner(primaryStage);
        colorStage.show();
    }
    
    // 将颜色转换为RGB代码
    private String toRGBCode(Color color) {
        return String.format("#%02X%02X%02X",
                (int) (color.getRed() * 255),
                (int) (color.getGreen() * 255),
                (int) (color.getBlue() * 255));
    }

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