java - 在线程 "JavaFX Application Thread"中获取异常，并具有时间线关键帧的重复子项

Question

我知道 Polyline sine = new Polyline(); 导致了错误，因为它试图为已经存在的东西创建一个新的类实例。如何清除每个关键帧的实例或在方法外部声明折线而不创建对角线及其创建的正弦波？ My Full Code

public BallOnCurvePane() {
        // Create an animation for moving the ball
        animation = new Timeline(
                new KeyFrame(Duration.millis(50), e -> moveBall()));
        animation.setCycleCount(Timeline.INDEFINITE);
        animation.play();
    }

protected void moveBall() {
        Polyline sine = new Polyline();
        ObservableList<Double> list = sine.getPoints();
        for (double x = -170.0; x <= 170.0; x++) {
            list.add(x + 200.0);
            list.add(80.0 - 50.0 * Math.sin((x / 100.0) * 2.0 * (double) Math.PI));
        }
        circle.setFill(ballColor);
        getChildren().addAll(sine, circle);

        pt.setRate(.25);
        pt.setPath(sine);
        pt.setNode(circle);
        pt.setCycleCount(Timeline.INDEFINITE);
        pt.setAutoReverse(true);
        pt.play();

    }

我的完整错误

Exception in thread "JavaFX Application Thread" java.lang.IllegalArgumentException: Children: duplicate children added: parent = BallOnCurvePane@13424ecf
    at javafx.scene.Parent$2.onProposedChange(Parent.java:454)
    at com.sun.javafx.collections.VetoableListDecorator.addAll(VetoableListDecorator.java:234)
    at com.sun.javafx.collections.VetoableListDecorator.addAll(VetoableListDecorator.java:103)
    at BallOnCurvePane.moveBall(BallOnCurvePane.java:68)
    at BallOnCurvePane.lambda$new$0(BallOnCurvePane.java:25)
    at com.sun.scenario.animation.shared.TimelineClipCore.visitKeyFrame(TimelineClipCore.java:239)
    at com.sun.scenario.animation.shared.TimelineClipCore.playTo(TimelineClipCore.java:180)
    at javafx.animation.Timeline.impl_playTo(Timeline.java:176)
    at javafx.animation.AnimationAccessorImpl.playTo(AnimationAccessorImpl.java:39)
    at com.sun.scenario.animation.shared.InfiniteClipEnvelope.timePulse(InfiniteClipEnvelope.java:110)
    at javafx.animation.Animation.impl_timePulse(Animation.java:1102)
    at javafx.animation.Animation$1.lambda$timePulse$25(Animation.java:186)
    at java.security.AccessController.doPrivileged(Native Method)
    at javafx.animation.Animation$1.timePulse(Animation.java:185)
    at com.sun.scenario.animation.AbstractMasterTimer.timePulseImpl(AbstractMasterTimer.java:344)
    at com.sun.scenario.animation.AbstractMasterTimer$MainLoop.run(AbstractMasterTimer.java:267)
    at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:506)
    at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:490)
    at com.sun.javafx.tk.quantum.QuantumToolkit.lambda$runToolkit$404(QuantumToolkit.java:319)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$148(WinApplication.java:191)
    at java.lang.Thread.run(Thread.java:745)

Answer 1

线路

getChildren().addAll(sine, circle);

每次添加相同的圆实例。无需多次添加节点。此外，由于折线仅代表球应采取的路径，因此无需将其添加为子项(除非您想绘制路径并沿其移动圆)。