如何在JavaFX

Question

我很难尝试用圆弧剪辑圆圈。我正在尝试重现这个恒温器

来自此video (starting at 43:45)开发人员说他使用Region s，Circle和Arc进行动画制作。所以我看不到如何用动画弧剪辑圆圈。

我的代码到目前为止......

//stroke is the circle without fill
    stroke.setClip(arc);

我收到以下错误：

Caused by: java.lang.IllegalArgumentException: Node's clip set to incorrect value (node already connected, node  = Circle[id=stroke, centerX=0.0, centerY=0.0, radius=200.0, fill=0x1f93ff00, stroke=0x63ff26ff, strokeWidth=30.0], clip = ObjectProperty [bean: Circle[id=stroke, centerX=0.0, centerY=0.0, radius=200.0, fill=0x1f93ff00, stroke=0x63ff26ff, strokeWidth=30.0], name: clip, value: null]).

那怎样才能解决这个问题？！我是仪表和恒温器应用程序的忠实粉丝。

提前致谢!!!

Answer 1

有一种更简单的方法可以达到预期效果：只需使用Arc而不使用fill并使用适当的strokeWidth。

示例：

@Override
public void start(Stage primaryStage) {
    DoubleProperty value = new SimpleDoubleProperty();
    DoubleProperty minValue = new SimpleDoubleProperty();
    DoubleProperty maxValue = new SimpleDoubleProperty();

    final double startOffset = 10;
    final double maxRange = 360 - 2 * startOffset;

    Arc arc = new Arc();
    arc.setFill(null);

    arc.setRadiusX(100);
    arc.setRadiusY(100);

    arc.setCenterX(110);
    arc.setCenterY(110);

    arc.setStrokeWidth(10);
    arc.setStroke(Color.WHITE.deriveColor(0, 0, 1, 0.5));
    arc.setStartAngle(270 - startOffset);
    arc.lengthProperty().bind(value.subtract(minValue).divide(maxValue.subtract(minValue)).multiply(-maxRange));

    Pane thermostatPane = new Pane();
    thermostatPane.setMinSize(220, 220);
    thermostatPane.getChildren().add(arc);
    thermostatPane.setStyle("-fx-background-color: orange");

    Slider minSlider = new Slider(0, 100, 0);
    Slider maxSlider = new Slider(0, 100, 100);
    Slider valueSlider = new Slider(0, 100, 20);

    valueSlider.setPrefWidth(200);
    maxSlider.setPrefWidth(200);
    minSlider.setPrefWidth(200);

    value.bind(valueSlider.valueProperty());
    minValue.bind(minSlider.valueProperty());
    maxValue.bind(maxSlider.valueProperty());

    Scene scene = new Scene(new VBox(10, thermostatPane, minSlider, valueSlider, maxSlider));

    primaryStage.setScene(scene);
    primaryStage.show();
}