Javafx Platform.runLater never running

Question

I basically want to be able to launch a new Javafx window (stage) after (and inside) my LWJGL/GLFW thread starts. I am basically doing:

Thread thread = new Thread(()->Platform.runLater(()->{
    Stage stage = new Stage();
    //Stage setup
    stage.show();
}));
thread.start();

thread being my game thread. But it never runs and I've tried a System.out.println() inside Platform.runLater() just to check it never runs.

Why does it never run and what can I do to fix it? Thanks.

EDIT: Just to clarify that the thread has definitely started and whatnot, if I do:

Thread thread = new Thread(()->{
    System.out.println("Before Platform.runLater()");
    Platform.runLater(()->System.out.println("Inside Platform.runLater()"));
    System.out.println("After Platform.runLater()");
});

It outputs:

Before Platform.runLater()
After Platform.runLater()

There seems to be no problem with the piece of code that you have provided. Can you check if the `thread.start();` is being called and thread is getting started. — ItachiUchiha, Mar 27 '15 at 14:33
With the code you've posted, the `Thread` is redundant. You could simply call `Platform.runLater(...)` from whatever thread you're in. What's the context here? Have the FX toolkit and application thread been started? — James_D, Mar 27 '15 at 14:46
Yeah sorry I've simplified it massively because there's a lot of other things in different classes in the thread. I absolutely know for a fact that the thread is started because that where my GLFW window comes from and I can see that. Basically I have my GLFW window/game and I want a Stage to also come up after a condition (so the GLFW window must come first). The FX application thread has started because I launch the GLFW window using an FX application. — user2513924, Mar 27 '15 at 16:23

score 49 · Accepted Answer · edited Dec 10 '18 at 12:21

49

Ok, I have found the solution to this!

If you run into any situation where all of your scenes end, the thread managing all of this will just peter out. To prevent this from happening, add this line before Platform.runLater:

Platform.setImplicitExit(false);
Platform.runLater(()->System.out.println("Inside Platform.runLater()"));

So long as this runs before the last scene ends, it will keep the thread alive, and you will not run into the problem of runLater() failing!

edited Dec 10 '18 at 12:21

asmmahmud

4,844
2
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47

answered Jun 10 '15 at 19:52

Draque Thompson

908
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Yep! That fixed it!! Thanks. – user2513924 Jun 13 '15 at 09:28
This solution seems to fix my problem too. – asmmahmud Dec 10 '18 at 12:12
This solution fixed the problem of reflecting webview content changes in the JFXpanel when getting navigated between menu bars. Thanks. – sriramdev Jun 19 '19 at 06:03
For me it was really weird, was running at first time opening of window and never after.Thanks bro – Harsh Apr 26 '22 at 05:21

Javafx Platform.runLater never running

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