JavaFX - LineChart水平标记问题

Question

我正在尝试向 JavaFX 中的折线图添加一条水平线。找到这个post在 SO 中，现在尝试修改它以在我的情况下工作，但是我收到错误，希望有人可以看到这里的问题是什么。

这是 Controller 代码:

package gems.view;

public class GUImainController implements Initializable, Observer
{
     final CategoryAxis xAxis = new CategoryAxis();
     final NumberAxis yAxis = new NumberAxis();

     private ArrayList<Float> tempArr = new ArrayList<>();
     private ArrayList<String> tempTimeArray = new ArrayList<>();

     private Series<String, Number> tempChart = new Series<>();

     @FXML
     private LineChartWithMarker<String, Number> lcTemperature = new LineChartWithMarker<>(xAxis,yAxis);

     @Override
     public void initialize(URL arg0, ResourceBundle arg1) 
     {      
          yAxis.setPrefWidth(35);   

          xAxis.setLabel("Temperature \\u00b0");
          yAxis.setLabel("Time");

          tempChart = new XYChart.Series<String, Number>();

          lcTemperature.getData().add(tempChart);


tempArr.add(observable.getLatestMeasurementsFromServer().getTemperature());
    tempTimeArray.add(observable.getLatestMeasurementsFromServer().getDateTime().getTime());

          for (int i = 0; i < tempArr.size(); i++)
          {
                tempChart.getData().add(new XYChart.Data<>(tempTimeArray.get(i), tempArr.get(i)));
          }         

                tempChart.getNode().lookup(".chart-series-line").setStyle("-fx-stroke: orange;");

    String s = "test";

    Data<String, Number> verticalMarker = new Data<>(s, 20);
    lcTemperature.addHorizontalValueMarker(verticalMarker);

 }

这是 LineChartWithMarker 类:

package gems.view;

import java.util.Objects;
import javafx.beans.InvalidationListener;
import javafx.beans.Observable;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.scene.chart.CategoryAxis;
import javafx.scene.chart.LineChart;
import javafx.scene.chart.NumberAxis;
import javafx.scene.shape.Line;

public class LineChartWithMarker<X,Y> extends LineChart
{
private ObservableList<Data<X, Y>> horizontalMarkers;   

public LineChartWithMarker(CategoryAxis xAxis, NumberAxis yAxis) 
{
    super(xAxis, yAxis);

    horizontalMarkers = FXCollections.observableArrayList(data -> new Observable[] {data.YValueProperty()});
    horizontalMarkers.addListener((InvalidationListener)observable -> layoutPlotChildren());
}

public void addHorizontalValueMarker(Data<X, Y> marker) 
{
    Objects.requireNonNull(marker, "the marker must not be null");
    if (horizontalMarkers.contains(marker)) return;
    Line line = new Line();
    marker.setNode(line );
    getPlotChildren().add(line);
    horizontalMarkers.add(marker);
}

public void removeHorizontalValueMarker(Data<X, Y> marker) {
    Objects.requireNonNull(marker, "the marker must not be null");
    if (marker.getNode() != null) {
        getPlotChildren().remove(marker.getNode());
        marker.setNode(null);
    }
    horizontalMarkers.remove(marker);
}

@Override
protected void layoutPlotChildren() {
    super.layoutPlotChildren();
    for (Data<X, Y> horizontalMarker : horizontalMarkers) {
        Line line = (Line) horizontalMarker.getNode();
        line.setStartX(0);
        line.setEndX(getBoundsInLocal().getWidth());
        line.setStartY(getYAxis().getDisplayPosition(horizontalMarker.getYValue()) + 0.5); // 0.5 for crispness
        line.setEndY(line.getStartY());
        line.toFront();
    }   
}   
}

这是 FXML(只是折线图的部分):

                          <LineChart fx:id="lcTemperature" minWidth="100.0" prefHeight="155.0" prefWidth="708.0" BorderPane.alignment="CENTER">
                            <xAxis>
                              <CategoryAxis side="BOTTOM" />
                            </xAxis>
                            <yAxis>
                              <NumberAxis autoRanging="false" lowerBound="20.0" minorTickCount="10" minorTickLength="10.0" side="LEFT" tickLabelGap="10.0" tickLength="20.0" tickUnit="1.0" upperBound="30.0" />
                            </yAxis>
                          </LineChart>

这是错误堆栈:

Exception in Application start method
java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.sun.javafx.application.LauncherImpl.launchApplicationWithArgs(LauncherImpl.java:389)
at com.sun.javafx.application.LauncherImpl.launchApplication(LauncherImpl.java:328)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at sun.launcher.LauncherHelper$FXHelper.main(Unknown Source)
Caused by: java.lang.RuntimeException: Exception in Application start method
at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:917)
at com.sun.javafx.application.LauncherImpl.lambda$launchApplication$154(LauncherImpl.java:182)
at java.lang.Thread.run(Unknown Source)
Caused by: javafx.fxml.LoadException: 
/C:/My%20Projects/GEMS_SEP2/GEMS_SEP2/bin/FXML/GUIgems.fxml:42

at javafx.fxml.FXMLLoader.constructLoadException(FXMLLoader.java:2601)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2579)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2441)
at javafx.fxml.FXMLLoader.load(FXMLLoader.java:2409)
at gems.view.GUIuserClient.start(GUIuserClient.java:33)
at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$161(LauncherImpl.java:863)
at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$174(PlatformImpl.java:326)
at com.sun.javafx.application.PlatformImpl.lambda$null$172(PlatformImpl.java:295)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.application.PlatformImpl.lambda$runLater$173(PlatformImpl.java:294)
at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$null$147(WinApplication.java:177)
... 1 more
Caused by: java.lang.IllegalArgumentException: Can not set gems.view.LineChartWithMarker field gems.view.GUImainController.lcTemperature to javafx.scene.chart.LineChart
at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(Unknown Source)
at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(Unknown Source)
at sun.reflect.UnsafeObjectFieldAccessorImpl.set(Unknown Source)
at java.lang.reflect.Field.set(Unknown Source)
at javafx.fxml.FXMLLoader.injectFields(FXMLLoader.java:1163)
at javafx.fxml.FXMLLoader.access$1600(FXMLLoader.java:103)
at javafx.fxml.FXMLLoader$ValueElement.processValue(FXMLLoader.java:857)
at javafx.fxml.FXMLLoader$ValueElement.processEndElement(FXMLLoader.java:765)
at javafx.fxml.FXMLLoader.processEndElement(FXMLLoader.java:2823)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2532)
... 12 more
Exception running application gems.view.GUIuserClient

顺便说一下，GUIgems.fxml:42 是我上面发布的 FXML 代码的最后一行。

此外，也许值得一提的是，如果我使用简单的折线图，则折线图可以正常工作，如下所示:

@FXML
private LineChart<String, Number> lcTemperature;

当我这样写时它不起作用:

@FXML
private LineChartWithMarker<String, Number> lcTemperature = new LineChartWithMarker<>(xAxis,yAxis);

Answer 1

好吧，如果有人发现自己处于同样的情况，我设法找到解决方案。

LineChartWithMarker 的构造函数需要如下所示:

public LineChartWithMarker(@NamedArg("xAxis") Axis<X> xAxis, 
        @NamedArg("yAxis") Axis<Y> yAxis) 
{
    super(xAxis, yAxis);

    horizontalMarkers = FXCollections.observableArrayList(data -> new Observable[] {data.YValueProperty()});
    horizontalMarkers.addListener((InvalidationListener)observable -> layoutPlotChildren());
}

FXML 需要如下所示:

<?import gems.view.LineChartWithMarker?>
<LineChartWithMarker fx:id="lcTemperature" minWidth="100.0" prefHeight="155.0" prefWidth="708.0" BorderPane.alignment="CENTER">
                            <xAxis>
                              <CategoryAxis side="BOTTOM" />
                            </xAxis>
                            <yAxis>
                              <NumberAxis autoRanging="false" lowerBound="20.0" minorTickCount="10" minorTickLength="10.0" side="LEFT" tickLabelGap="10.0" tickLength="20.0" tickUnit="1.0" upperBound="30.0" />
                            </yAxis>
                          </LineChartWithMarker>