功能说明：

1、当鼠标移入饼图块时，该块位置发生偏移。

2、鼠标离开后，该块回复到原来位置。

先看效果图：

实现技巧: 1、计算鼠标所在块的偏移角度。 从上图中可以看出：在javafx中，第一个数据块的位置从0开始，按逆时针方向一次排列。 因此数据块的偏移角度为，它之前所有数据块的角度之和，再加上本身所占角度的一半。

2、数据块角度的计算。 可以根据数据块所占数据的百分比计算对应的角度。 参考以下代码：

    private static double calcAngle(PieChart.Data d) {double total = 0;for (PieChart.Data tmp : d.getChart().getData()) {total += tmp.getPieValue();}return 360 * (d.getPieValue() / total);}

3、注意y坐标的计算，由于fx的y轴和直角坐标系相反，所以移动y坐标要取反。

全部源码:

public class PieChartSample extends Application {@Overridepublic void start(Stage primaryStage) {BorderPane p = new BorderPane();ObservableList pieChartData = FXCollections.observableArrayList(new PieChart.Data("Austria", 8_430_558),new PieChart.Data("Swiss", 7_701_900),new PieChart.Data("Germany", 81_882_342),new PieChart.Data("France", 62_793_432),new PieChart.Data("Spain", 46_661_950),new PieChart.Data("Italy", 60_245_846));PieChart chart = new PieChart(pieChartData);// chart.setStyle("-fx-pie-label-visible: false");for (PieChart.Data d : pieChartData) {d.getNode().setOnMouseEntered(new MouseHoverAnimation(d, chart));d.getNode().setOnMouseExited(new MouseExitAnimation());}chart.setClockwise(false);p.setCenter(chart);Scene s = new Scene(p);primaryStage.setScene(s);primaryStage.setWidth(600);primaryStage.setHeight(600);primaryStage.setTitle("动态饼图");primaryStage.show();}public static void main(String[] args) {launch(args);}static class MouseHoverAnimation implements EventHandler {static final Duration ANIMATION_DURATION = new Duration(500);static final double ANIMATION_DISTANCE = 0.15;private double cos;private double sin;private PieChart chart;public MouseHoverAnimation(PieChart.Data d, PieChart chart) {this.chart = chart;double start = 0;double angle = calcAngle(d);for (PieChart.Data tmp : chart.getData()) {if (tmp == d) {break;}start += calcAngle(tmp);}cos = Math.cos(Math.toRadians(start + angle / 2));sin = Math.sin(Math.toRadians(start + angle / 2));}@Overridepublic void handle(MouseEvent arg0) {Node n = (Node) arg0.getSource();double minX = Double.MAX_VALUE;double maxX = Double.MAX_VALUE * -1;for (PieChart.Data d : chart.getData()) {minX = Math.min(minX, d.getNode().getBoundsInParent().getMinX());maxX = Math.max(maxX, d.getNode().getBoundsInParent().getMaxX());}double radius = maxX - minX;System.out.println("cos:" + cos);System.out.println("sin" + sin);TranslateTransitionBuilder.create().toX((radius * ANIMATION_DISTANCE) * cos).toY((radius * ANIMATION_DISTANCE) * (-sin)).duration(ANIMATION_DURATION).node(n).build().play();}private static double calcAngle(PieChart.Data d) {double total = 0;for (PieChart.Data tmp : d.getChart().getData()) {total += tmp.getPieValue();}return 360 * (d.getPieValue() / total);}}static class MouseExitAnimation implements EventHandler {@Overridepublic void handle(MouseEvent event) {TranslateTransitionBuilder.create().toX(0).toY(0).duration(new Duration(500)).node((Node) event.getSource()).build().play();}}
}

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