Javafx 拖动窗口时隐藏关联菜单

我感兴趣的是，当我拖动主舞台或窗口时，如何隐藏上下文菜单？我正在研究这个验证器示例，我注意到与Java8中的上下文菜单相关的几个问题

public class MainApp extends Application
{

    @Override
    public void start(Stage stage) throws Exception
    {

//        setUserAgentStylesheet(STYLESHEET_CASPIAN);
        stage.setTitle("Validation Demo");
        BorderPane borderPane = new BorderPane();

        borderPane.setCenter(loadLoginScreen());
        Scene scene = new Scene(borderPane, 700, 500);
        scene.getStylesheets().add(
            MainApp.class.getResource("/styles/validator.css")
            .toExternalForm());
        stage.setScene(scene);
        stage.show();
    }

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

    private GridPane loadLoginScreen()
    {

        GridPane grid = new GridPane();
        grid.setAlignment(Pos.CENTER);
        grid.setHgap(10);
        grid.setVgap(10);
        grid.setPadding(new Insets(25, 25, 25, 25));

        Text scenetitle = new Text("Welcome");
        scenetitle.setFont(Font.font("Tahoma", FontWeight.NORMAL, 20));
        grid.add(scenetitle, 0, 0, 2, 1);

        Label userName = new Label("User Name:");
        grid.add(userName, 0, 1);

        final TextField userTextField = new TextField();
        grid.add(userTextField, 1, 1);

        Label pw = new Label("Password:");
        grid.add(pw, 0, 2);

        final PasswordField pwBox = new PasswordField();
        grid.add(pwBox, 1, 2);

        Button btn = new Button("Sign in");
        HBox hbBtn = new HBox(10);
        hbBtn.setAlignment(Pos.BOTTOM_RIGHT);
        hbBtn.getChildren().add(btn);
        grid.add(hbBtn, 1, 4);

        final Text actiontarget = new Text();
        grid.add(actiontarget, 1, 6);

        // Context Menu for error messages
        final ContextMenu usernameValidator = new ContextMenu();
        usernameValidator.getStyleClass().add("validator");

        usernameValidator.setAutoHide(false);

        final ContextMenu passValidator = new ContextMenu();
        passValidator.getStyleClass().add("validator");

        passValidator.setAutoHide(false);

        // Action on button press
        btn.setOnAction(new EventHandler<ActionEvent>()
        {

            @Override
            public void handle(ActionEvent e)
            {
                // Clearing message if any
                actiontarget.setText("");

                // Checking if the userTextField is empty
                if (userTextField.getText().equals(""))
                {

                    MenuItem cc = new MenuItem("Please enter username");
                    cc.getStyleClass().add("validator-item");

                    usernameValidator.getItems().clear();
                    usernameValidator.getItems().add(cc);
                    usernameValidator.show(userTextField, Side.RIGHT, 10, 0);
                }
                // Checking if the pwBox is empty
                if (pwBox.getText().equals(""))
                {
                    MenuItem dcc = new MenuItem("Please enter password");
                    dcc.getStyleClass().add("validator-item");

                    passValidator.getItems().clear();
                    passValidator.getItems().add(dcc);
                    passValidator.show(pwBox, Side.RIGHT, 10, 0);
                }
                // If both of the above textFields have values
                if (!pwBox.getText().equals("")
                    && !userTextField.getText().equals(""))
                {
                    actiontarget.setFill(Color.GREEN);
                    actiontarget.setText("Welcome");
                }
            }
        });

        userTextField.focusedProperty().addListener(
            new ChangeListener<Boolean>()
            {
                @Override
                public void changed(
                    ObservableValue<? extends Boolean> arg0,
                    Boolean oldPropertyValue, Boolean newPropertyValue)
                {
                    if (newPropertyValue)
                    {
                        // Clearing message if any
                        actiontarget.setText("");
                        // Hiding the error message
                        usernameValidator.hide();
                    }
                    }
            });

        pwBox.focusedProperty().addListener(new ChangeListener<Boolean>()
        {
            @Override
            public void changed(ObservableValue<? extends Boolean> arg0,
                Boolean oldPropertyValue, Boolean newPropertyValue)
            {
                if (newPropertyValue)
                {
                    // Clearing message if any
                    actiontarget.setText("");
                    // Hiding the error message
                    passValidator.hide();
                }
            }
        });
        return grid;
    }

}

---

例如，我可以为Stage添加事件处理程序吗？

最简单的选择是只打开autohide，而不是像在代码中那样禁用它。您也不需要焦点属性侦听器

.validator {
  -fx-background-color: #006699;
  -fx-text-fill: white;
  -fx-padding: 0;
}

.validator:hover {
  -fx-background-color: #006699;
  -fx-text-fill: white;
}

.validator-item .label {
  -fx-text-fill: white;
}

.validator-item:focused .label {
  -fx-text-fill: white;
}