如何使用时间轴正确启动 javafx 动画？

Question

我正在尝试使用从该网站收集的代码来制作一个可以循环播放的应用程序。当我现在单击时 - 它会创建一个圆圈，该圆圈似乎只是在适当的地方振动并且不会从边界反弹。

这是解决我的问题的代码，谢谢大家

@FXML
private AnchorPane anchorPane;
@FXML
private Label ballCountLabel;

public int ballCount = 0;
public int mouseClick = 0;

Circle[] balls = new Circle[1000];

@Override
public void initialize(URL url, ResourceBundle rb) {
    pane.setBackground(new Background(new BackgroundFill(Color.WHITE, CornerRadii.EMPTY, Insets.EMPTY)));
    AnchorPane.setTopAnchor(pane, 0.0);
    AnchorPane.setLeftAnchor(pane, 0.0);
    AnchorPane.setTopAnchor(pane, 0.0);
    AnchorPane.setRightAnchor(pane, 0.0);
}

@FXML
private void mouseAddBall(MouseEvent event) throws Exception {

    balls[mouseClick] = new Circle(15, Color.BLANCHEDALMOND);
    balls[mouseClick].relocate(event.getSceneX(), event.getSceneY());
    pane.getChildren().add(balls[mouseClick]);
    ballCount++;
    ballCountLabel.setText("Ball Count: " + ballCount);
    addBallMovement(balls[mouseClick]);
    mouseClick++;
}
public void addBallMovement(Circle b){

    final Timeline loop = new Timeline(new KeyFrame(Duration.millis(10), new EventHandler<ActionEvent>() {

        double deltaX = 3;
        double deltaY = 3;

        @Override
        public void handle(ActionEvent t) {
            b.setLayoutX(b.getLayoutX() + deltaX);
            b.setLayoutY(b.getLayoutY() + deltaY);

            final Bounds bounds = pane.getBoundsInParent();

            final boolean atRightBorder = b.getLayoutX() >= (bounds.getMaxX() - b.getRadius());
            final boolean atLeftBorder = b.getLayoutX() <= (bounds.getMinX() + b.getRadius());
            final boolean atBottomBorder = b.getLayoutY() >= (bounds.getMaxY() - b.getRadius());
            final boolean atTopBorder = b.getLayoutY() <= (bounds.getMinY() + b.getRadius());

            if (atRightBorder || atLeftBorder) {
                deltaX *= -1;
            }
            if (atBottomBorder || atTopBorder) {
                deltaY *= -1;
            }
        }
    }));
    loop.setCycleCount(Timeline.INDEFINITE);
    loop.play();

Answer 1

我将 Ball 更改为 Circle 以测试您的代码。在向当前球添加移动之前，您将更改为 balls 数组中的下一个球。这可能会给你一个 NullPointerException.

改变

balls[mouseClick] = new Circle(event.getSceneX(), event.getSceneY(), 
Math.random() * 20);
pane.getChildren().add(balls[mouseClick]);
mouseClick++;
ballCount++;
ballCountLabel.setText("Ball Count: " + ballCount);
addBallMovement(balls[mouseClick]);  //<--You want to move the current ball. This code needs to be before mouseClick++

收件人：

balls[mouseClick] = new Circle(event.getSceneX(), event.getSceneY(), 
Math.random() * 20);
pane.getChildren().add(balls[mouseClick]);
addBallMovement(balls[mouseClick]);
mouseClick++;
ballCount++;
ballCountLabel.setText("Ball Count: " + ballCount);

如何使用时间轴正确启动 javafx 动画？

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