JavaFX: can you create a stage that doesn't show on the task bar and is undecorated? - javafx-8

Question

I'm trying to create a stage that doesn't appear on the Windows task bar and is undecorated (no borders and no close/minimize/maximize buttons). My end goal is to create a tray icon application that will pop up notification windows.
It's similar to this question where I want the behavior of both StageStyle.UTILITY (which prevents the stage from showing on the task bar) and StageStyle.TRANSPARENT (which is a completely undecorated window).
The referenced question doesn't work for me because I don't have a parent stage from which to make a modal window. Any ideas on how to get this to work? Thanks

Answer 1

I was able to workaround this issue with the following code:
Stage stage = new Stage();
stage.initStyle(StageStyle.UTILITY);
stage.setMaxHeight(0);
stage.setMaxWidth(0);
stage.setX(Double.MAX_VALUE);
StageStyle.UTILITY will avoid creating a taskbar icon. I set the width and height to 0 make the window small and then use stage.setX(Double.MAX_VALUE) to place it far off screen so it doesn't show up. It's a bit hokey, but it seems to work fine.

Answer 2

JavaFX doesn't support the feature you request
You cannot do what you are asking (not show a task bar icon for an undecorated or transparent stage) using just the core Java 8 classes.
If you wish, file a feature request for this in the JavaFX issue tracker.
You could write some native JNI code and perhaps tell Windows not to display a task bar icon for your application. I do not know how you would do this.
Suggestion on task bar icons
I think it is fairly standard windowing toolkit behaviour to show the main application window in the task bar when the main application window is not hidden, so I suggest not trying to circumvent that standard behaviour.
Suggestion on notifications and tray icons
This isn't directly related to your question title, but is just comment on the end goal of your task - notifications for tray icons.
Most tray based applications I have seen don't have a task bar icon when the window associated with the tray icon is hidden, but do have a task bar icon when the window associated with the tray icon is displayed - so I suggest you stick with that setup.
Also, notifications are a standard part of the system tray icon infrastructure itself, so I suggest you use the standard mechanisms for system tray icon notifications, rather than using your own. This will also allow the user to configure whether the tray icon and it's notifications are shown using the standard OS tray icon and notification management UIs.
I created a sample application which uses the AWT SystemTray API to provide a System tray for a JavaFX application which uses some of the suggestions from this section. You can try it out if you like.
Full system tray support will come to JavaFX (probably with Java 9) when RT-17503 Provide system tray support is implemented.

Answer 3

This question is not really fresh, but I had the same problem and found no solution at first, but here is my workaround :)
The best solution I found was to set the primaryStage to style Utility and to make all childStages to Style Undecorated. Then set the opacity of the primaryStage to 0.0 so its not visible:
PrimaryStage:
primaryStage.initStyle(StageStyle.UTILITY);
primaryStage.setOpacity(0);
primaryStage.show();
Childs:
this.initOwner(owner);
this.initStyle(StageStyle.UNDECORATED);
Example code
public void start(Stage primaryStage) throws IOException{
//make primaryStage utility
primaryStage.initStyle(StageStyle.UTILITY);
primaryStage.setOpacity(0);
Stage secondaryStage = new Stage();
secondaryStage.initOwner(primaryStage);
//make secondaryStage transparent
secondaryStage.initStyle(StageStyle.TRANSPARENT);
//load ui via FXMLLoader
FXMLLoader loader = new FXMLLoader(getClass().getResource("/ui.fxml"));
AnchorPane pane = loader.load();//example with anchor pane
Scene scene = new Scene(pane,400,400); //example width and height
scene.setFill(Color.TRANSPARENT); //make scene transparent as well
secondaryStage.setScene(scene);
primaryStage.show();
secondaryStage.show();
}

Answer 4

Inspired by #Loki solution with a little upgrade (in my opinion)
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;
import javafx.stage.StageStyle;
public class TransparentAndUtilityStageApp extends Application {
public static void main(String[] args) {
launch(args);
}
#Override
public void start(Stage primaryStage) throws Exception {
primaryStage.initStyle(StageStyle.UTILITY);
primaryStage.setOpacity(0.);
primaryStage.show();
Stage stage = new Stage();
Label label = new Label("Rainmeter");
StackPane stackPane = new StackPane(label);
stackPane.setPrefSize(600, 400);
stackPane.setStyle("-fx-background-color: transparent;");
Scene scene = new Scene(stackPane);
scene.setFill(null);
stage.initOwner(primaryStage);
stage.initStyle(StageStyle.TRANSPARENT);
stage.setScene(scene);
stage.show();
}
}

Answer 5

JavaFX DOES support that.
Don't put the main() method in your Application class. Just create another class to be your main class:
public class FxApplication extends Application {
}
public class Main {
public static void main(String[] args) {
PlatformImpl.setTaskbarApplication(false);
Application.launch(FxApplication.class, args);
}
}

Answer 6

As far as I know, JavaFX and Swing are interoperable and swing supports this feature. So if you can use Swing, integrate something like this into your application:
class MyFrame extends JFrame {
// ...
MyFrame() {
setUndecorated(true);
setType(Type.UTILITY);
}
// ...
}
I haven't tried this but other SO questions like this will probably help you on how to use Swing in JavaFX.