java - JavaFX 8-在右侧的TitledPane中添加图形

我想在TitledPane的标题中添加一个小图标。因此，我设置了一个空标题，并添加了一个包含HBox和Label的ImageView作为图形。这样，图标显示在文本结尾附近。我希望它始终显示在TitledPane的右边界旁边。
我怎样才能做到这一点？
我还尝试使用BorderPane并将Label添加到中心，并在右侧添加ImageView，但是BorderPane没有获得TitledPane的最大大小。
所以我试图将MaxWidth设置为Max-Value，但这没有帮助

有人知道该怎么办吗？

**编辑:**我创建的“自定义”控件将在stage.setOnShown中调用的方法中初始化。

public class CustomTitledPane extends TitledPane {
private Image alert;
private Image registered;
private Image deleted;
private ImageView img;

public CustomTitledPane(String titleText, Node node) {
    super(titleText, node);
    setAnimated(true);
    setCollapsible(true);
    img = new ImageView();
    img.setFitHeight(10d);
    img.setPreserveRatio(true);
    img.setSmooth(true);
    setGraphic(img);
    setContentDisplay(ContentDisplay.RIGHT);
    // apply css and force layout of nodes
    applyCss();
    layout();

    // title region
    Node titleRegion = lookup(".title");
    // padding
    Insets padding = ((StackPane) titleRegion).getPadding();
    // image width
    double graphicWidth = img.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;
    System.out.println("w: " + graphicWidth + " " + arrowWidth + " "
            + labelWidth);
    graphicTextGapProperty().bind(widthProperty().subtract(nodesWidth));
    try {
        alert = new Image(new FileInputStream("img/Alert.png"));
        registered = new Image(new FileInputStream("img/Registered.png"));
        deleted = new Image(new FileInputStream("img/Deleted.png"));
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    }
} }

这是TitledPane的CSS:

    .titled-pane {
    -fx-text-fill: #006FD8;
}

.titled-pane > .title {
    -fx-background-color: transparent;
    -fx-border-color: linear-gradient(to right, white 0%, grey 30%, grey 70%, white 100%) transparent transparent transparent;
}

.titled-pane:expanded > .title {
    -fx-border-color: grey transparent transparent transparent;
    -fx-background-color: linear-gradient(to bottom, #DCE7F5, white);
}

.titled-pane:expanded > *.content {
    -fx-border-width: 0;
}

最佳答案

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。

@Override
public 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);
    }
}