如果所有者窗口不可见，则 JavaFX 弹出窗口不会显示

Question

尝试将 Stage 设置为 Popup 的所有者，但如果所有者不是应用程序的主 Stage，则 Popup 不会出现。

public void popup(Window owner, String mensagem) {
    Popup popup = new Popup();
    popup.setAutoHide(true);
    popup.setHideOnEscape(true);

    Label label = new Label(mensagem);
    label.setBackground(new Background(new BackgroundFill(Color.CORNSILK, null, null)));

    popup.getContent().add(label);
    popup.setOnShown((event) -> {
        FadeTransition fade = new FadeTransition(Duration.seconds(5), label);
        fade.setOnFinished((e) -> {
            popup.hide();
        });
        fade.play();
    });

    popup.show(owner);
}

子阶段:

public class JanelaModal extends Stage {

    public JanelaModal(String title) {
        super(StageStyle.DECORATED);
        setTitle(title);
        initOwner(Main.getInstance().getStage());
        initModality(Modality.APPLICATION_MODAL);
        setResizable(false);
    }

    public void setGui(Parent gui) {
        if (getScene() != null) {
            getScene().setRoot(gui);
        } else {
            setScene(new Scene(gui));
        }
    }

}

Answer 1

在显示弹出窗口之前，您必须在子舞台上调用 show(...)。

使用您的类JanelaModal我编写了一个简单的测试Java FX应用程序。这是主类

public class Main extends Application {

    private static Main instance;
    private Stage stage;

    @Override
    public void start(Stage primaryStage) throws Exception{
        instance = this;
        this.stage = stage;
        Parent root = FXMLLoader.load(getClass().getResource("sample.fxml"));
        primaryStage.setTitle("Hello World");
        primaryStage.setScene(new Scene(root, 300, 275));
        //primaryStage.show(); //Don't show main stage

        JanelaModal modal = new JanelaModal("TEST");
        modal.setWidth(300);
        modal.setHeight(300);
        modal.show();
        popup(modal, "Test message");
    }

    //Copied and pasted from the question post
    public void popup(Window owner, String mensagem) {
        Popup popup = new Popup();
        popup.setAutoHide(true);
        popup.setHideOnEscape(true);

        Label label = new Label(mensagem);
        label.setBackground(new Background(new BackgroundFill(Color.CORNSILK, null, null)));

        popup.getContent().add(label);
        popup.setOnShown((event) -> {
            FadeTransition fade = new FadeTransition(Duration.seconds(5), label);
            fade.setOnFinished((e) -> {
                popup.hide();
            });
            fade.play();
        });

        popup.show(owner);
    }

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

    public static Main getInstance() {
        return instance;
    }

    public Stage getStage() {
        return stage;
    }
}

这就是结果

弹出窗口显示在“子”阶段。如果你打电话

popup(modal, "Test message");

但是你不打电话

modal.show();

弹出窗口(和舞台)将不会显示。

希望我能有所帮助:)