Re: Re: Property updates

[goddard at seznam.cz]

Hi,

thanks for the answer. I've thought that my code does this:
- create circle at random coords
- create random end coords
- create animation with all these coords
- call setOnFinished every time when animation ends
- inside handle, do following:
-- assign the current end coords to the target coords, so the next animation starts at the end
-- generate new end coords, so the next animation ends at different coords
-- play next animation

>From the point where I'm callung the setOnFinished, it should be like a never-ending loop. Accordning to the println output, I'm updating the end coords, but the circle coords are not updated even I'm calling set() on the cX/Y property.
I'm not sure what I should change in the code so it works properly.

Apologies, Jiri

------------ Původní zpráva ------------
Od: Pavel Safrata <pavel.safrata at oracle.com>
Předmět: Re: Property updates
Datum: 11.6.2012 13:48:14
----------------------------------------
Hello Jiri,
the coordinates are updated during the animation, but always finish on 
the same value. It's because you create the timeline passing the current 
values of the x and y properties and then run it over and over without 
updating it, so it always finishes with the circle on the same 
coordinates (the first random values generated for x an y). The pause is 
caused by the fact that your code makes the second run of the timeline 
begin on the same place where it ends (so the animation runs and moves 
the circle about zero pixels).
With regards,
Pavel

On 11.6.2012 12:48, goddard at seznam.cz wrote:
> This is the output from the println statements:
> centerXDoubleProperty [bean: Circle at 157a5c3, name: centerX, value:
396.34924225837125]
> x: DoubleProperty [value: 396.34924225837125]
> centerXDoubleProperty [bean: Circle at 157a5c3, name: centerX, value:
396.34924225837125]
> x: DoubleProperty [value: 563.9584002793741]
> centerXDoubleProperty [bean: Circle at 157a5c3, name: centerX, value:
396.34924225837125]
> x: DoubleProperty [value: 337.0834495091644]
>
> As you can see, the centerX value doesn't change at all. Any help is
appreciated.
>
> Regards, jiri
>
> ------------ Původní zpráva ------------
> Od:<goddard at seznam.cz>
> Předmět: Property updates
> Datum: 10.6.2012 22:54:59
> ----------------------------------------
> Hello,
>
> the following code should create a Circle at random coords and animate the
> translation to random coords. The point is to randomly translate the circle
from
> one location to another successively:
>
> package boyle;
>
> import javafx.animation.KeyFrame;
> import javafx.animation.KeyValue;
> import javafx.animation.Timeline;
> import javafx.animation.TimelineBuilder;
> import javafx.application.Application;
> import javafx.beans.property.DoubleProperty;
> import javafx.beans.property.SimpleDoubleProperty;
> import javafx.event.ActionEvent;
> import javafx.event.EventHandler;
> import javafx.scene.Group;
> import javafx.scene.Scene;
> import javafx.scene.paint.Color;
> import javafx.scene.shape.Circle;
> import javafx.scene.shape.CircleBuilder;
> import javafx.stage.Stage;
> import javafx.util.Duration;
>
> /**
>   *
>   * @author jiri
>   */
> public class Boyle extends Application {
>
>      public static final int WIDTH = 800;
>      public static final int HEIGHT = 512;
>
>      /**
>       * @param args the command line arguments
>       */
>      public static void main(String[] args) {
>          launch(args);
>      }
>
>      // end the animation at random coords
>      private DoubleProperty x = new SimpleDoubleProperty(Math.random() *
WIDTH);
>      private DoubleProperty y = new SimpleDoubleProperty(Math.random() *
> HEIGHT);
>
>      @Override public void start(Stage primaryStage) {
>          final Circle c = CircleBuilder.create()
>                  // start the animation at random coords
>                  .centerX(Math.random() * WIDTH)
>                  .centerY(Math.random() * HEIGHT)
>                  .radius(15).fill(Color.BLACK)
>                  .build();
>
>          final DoubleProperty[] randCoords = {x, y};
>
>          final Timeline t = TimelineBuilder.create()
>                  .keyFrames(new KeyFrame(Duration.seconds(5),
>                  new KeyValue(c.centerXProperty(), randCoords[0].get()),
>                  new KeyValue(c.centerYProperty(), randCoords[1].get())))
>                  .build();
>
>          // refreshes coords at every end of the animation
>          t.setOnFinished(new EventHandler<ActionEvent>() {
>
>              @Override
>              public void handle(ActionEvent ae) {
>                  System.out.println("centerX"+ c.centerXProperty());
>                  // set animation end coords to the target
>                  c.centerXProperty().set(randCoords[0].get());
>                  c.centerYProperty().set(randCoords[1].get());
>                  System.out.println("x: "+ randCoords[0]);
>                  // generate new coords for the animation end
>                  randCoords[0].set(Math.random() * WIDTH);
>                  randCoords[1].set(Math.random() * HEIGHT);
>                  t.play();
>              }
>          });
>
>          t.play();
>
>          Group root = new Group();
>          root.getChildren().add(c);
>
>          Scene scene = new Scene(root, WIDTH, HEIGHT);
>
>          primaryStage.setTitle("@javafxcz - Boyle - www.dredwerkz.cz");
>          primaryStage.setScene(scene);
>          primaryStage.show();
>      }
> }
>
> However, the circle appears moving to its target coords instead to its end
> coords, and update of the target coords doesn't work - unlike for the end
> coords. Plus, there's a significant 1-2 seconds long pause before the
animation
> starts again in the handler, but just for the first time. Then it runs
> smoothly.
> Help in form of explanation / code sample is appreciated.
>
> Regards, Jiri
>
>