HEADS-UP: Threading restriction for Animation play, pause, stop now enforced USE CASE

[Jurgen Doll]

Here's an example as requested by Nir:

public class FxTimeLineTest extends Application

{

     private BorderPane bp = new BorderPane( new Label("Loading") );



     public static void main( String[] args ) {

         launch( FxTimeLineTest.class, args );

     }



     @Override

     public void start( Stage primaryStage ) throws Exception {

         new Thread( new LoadScene() ).start();

         primaryStage.setScene( new Scene( bp, 300, 200 ) );

         primaryStage.setTitle( "Memory Usage" );

         primaryStage.show();

     }



     private class LoadScene extends Task<Parent> {

         @Override protected Parent call() throws Exception {

             Parent p = FXMLLoader.load(  
getClass().getResource("TestView.fxml") );

             Thread.sleep( 1000 );

             return p;

         }



         @Override protected void succeeded() {

             bp.setCenter( getValue() );

         }



         @Override protected void failed() {

             getException().printStackTrace();

         }

     }

}


------------------------------------------------------------------------------------------------------


public class TestView

{

     @FXML private Label memory;



     private static final double  MEGABYTE = 1024 * 1024;



     @FXML private void initialize()

     {

         var updater = new Timeline

         (

             new KeyFrame( Duration.seconds(2.5), event ->

             {

                 var runtime = Runtime.getRuntime();

                 double maxMemory = runtime.maxMemory() / MEGABYTE;

                 double usedMemory = (runtime.totalMemory() -  
runtime.freeMemory()) / MEGABYTE;

                 memory.setText( (int) usedMemory + " MB / " + (int)  
maxMemory +" MB" );

             })

         );



         updater.setCycleCount(Animation.INDEFINITE);
         // This FXML is being loaded on a background thread

         updater.play();

     }

}


------------------------------------------------------------------------------------------------------

TestView.fxml



<?xml version="1.0" encoding="UTF-8"?>



<?import javafx.scene.control.Label?>

<?import javafx.scene.layout.StackPane?>



<StackPane xmlns:fx="http://javafx.com/fxml/1" fx:controller="TestView">

    <children>

       <Label fx:id="memory" text="Current / Max MB" >

          <properties hashCode="12345" />

       </Label>

    </children>

</StackPane>




On Sat, 20 Jan 2024 17:08:41 +0200, Nir Lisker <nlisker at gmail.com> wrote:

> Hi Jurgen,
>
> What I'm confused about the most is what it is you are actually trying  
> to do that necessitates the use of animations outside of the FX thread.  
> >You said that you need to initialize controls on another thread, and  
> that you are using Task (both of which are fine), but how does playing  
> >animations relate? Playing an animation is something that is done  
> explicitly, usually in order to manipulate data. Can you give a real use  
> >case, like a minimized version of what you're doing?
>
> - Nir
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