根据OP在其已编辑问题上显示的代码，此代码解决了以下事实：在显示阶段之前，在自定义类上在侦听器上创建了标题窗格。
@Overridepublic void start(Stage primaryStage) { Scene scene = new Scene(new StackPane(), 300, 250); primaryStage.setScene(scene); primaryStage.setonShown(e -> { CustomTitledPane customTitledPane = new CustomTitledPane("Title", new StackPane(new Label("Graphic to the Right"))); scene.setRoot(customTitledPane); customTitledPane.applyCss(); customTitledPane.layout(); // title region Node titleRegion=customTitledPane.lookup(".title"); // padding Insets padding=((StackPane)titleRegion).getPadding(); // image width double graphicWidth=customTitledPane.getGraphic().getLayoutBounds().getWidth(); // arrow double arrowWidth=titleRegion.lookup(".arrow-button").getLayoutBounds().getWidth(); // text double labelWidth=titleRegion.lookup(".text").getLayoutBounds().getWidth(); double nodesWidth = graphicWidth+padding.getLeft()+padding.getRight()+arrowWidth+labelWidth; customTitledPane.graphicTextGapProperty().bind(customTitledPane.widthProperty().subtract(nodesWidth)); }); primaryStage.show();}class CustomTitledPane extends TitledPane { public CustomTitledPane(String titleText, Node node) { super(titleText, node); setAnimated(true); setCollapsible(true); ImageView img = new ImageView(new Image(getClass().getResource("unlock24.png").toExternalForm())); img.setFitHeight(10d); img.setPreserveRatio(true); img.setSmooth(true); setGraphic(img); setContentDisplay(ContentDisplay.RIGHT); }}
