LineChart中的缩放功能

Question

尝试在折线图中绘制矩形时出现异常。我想将此JavaFX应用程序转换为JavaFXML：

package javafxapplication24;

import java.util.Collections;
import java.util.Random;

import javafx.application.Application;
import javafx.beans.binding.BooleanBinding;
import javafx.beans.property.ObjectProperty;
import javafx.beans.property.SimpleObjectProperty;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.geometry.Insets;
import javafx.geometry.Point2D;
import javafx.geometry.Pos;
import javafx.scene.Node;
import javafx.scene.Scene;
import javafx.scene.chart.Axis;
import javafx.scene.chart.LineChart;
import javafx.scene.chart.NumberAxis;
import javafx.scene.chart.XYChart.Data;
import javafx.scene.chart.XYChart.Series;
import javafx.scene.control.Button;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.HBox;
import javafx.scene.layout.StackPane;
import javafx.scene.paint.Color;
import javafx.scene.shape.Rectangle;
import javafx.stage.Stage;


public class JavaFXApplication24 extends Application {


    private static final int NUM_DATA_POINTS = 1000 ;

    @Override
    public void start(Stage primaryStage) {
        final LineChart<Number, Number> chart = createChart();

        final StackPane chartContainer = new StackPane();
        chartContainer.getChildren().add(chart);

        final Rectangle zoomRect = new Rectangle();
        zoomRect.setManaged(false);
        zoomRect.setFill(Color.LIGHTSEAGREEN.deriveColor(0, 1, 1, 0.5));
        chartContainer.getChildren().add(zoomRect);

        setUpZooming(zoomRect, chart);

        final HBox controls = new HBox(10);
        controls.setPadding(new Insets(10));
        controls.setAlignment(Pos.CENTER);

        final Button zoomButton = new Button("Zoom");
        final Button resetButton = new Button("Reset");
        zoomButton.setOnAction(new EventHandler<ActionEvent>() {
            @Override
            public void handle(ActionEvent event) {
                doZoom(zoomRect, chart);
            }
        });
        resetButton.setOnAction(new EventHandler<ActionEvent>() {
            @Override
            public void handle(ActionEvent event) {
                final NumberAxis xAxis = (NumberAxis)chart.getXAxis();
                xAxis.setLowerBound(0);
                xAxis.setUpperBound(1000);
                final NumberAxis yAxis = (NumberAxis)chart.getYAxis();
                yAxis.setLowerBound(0);
                yAxis.setUpperBound(1000);

                zoomRect.setWidth(0);
                zoomRect.setHeight(0);
            }
        });
        final BooleanBinding disableControls = 
                zoomRect.widthProperty().lessThan(5)
                .or(zoomRect.heightProperty().lessThan(5));
        zoomButton.disableProperty().bind(disableControls);
        controls.getChildren().addAll(zoomButton, resetButton);

        final BorderPane root = new BorderPane();
        root.setCenter(chartContainer);
        root.setBottom(controls);

        final Scene scene = new Scene(root, 600, 400);
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    private LineChart<Number, Number> createChart() {
        final NumberAxis xAxis = createAxis();
        final NumberAxis yAxis = createAxis();      
        final LineChart<Number, Number> chart = new LineChart<>(xAxis, yAxis);
        chart.setAnimated(false);
        chart.setCreateSymbols(false);
        chart.setData(generateChartData());     
        return chart ;
    }

    private NumberAxis createAxis() {
        final NumberAxis xAxis = new NumberAxis();
        xAxis.setAutoRanging(false);
        xAxis.setLowerBound(0);
        xAxis.setUpperBound(1000);
        return xAxis;
    }

    private ObservableList<Series<Number, Number>> generateChartData() {
        final Series<Number, Number> series = new Series<>();
        series.setName("Data");
        final Random rng = new Random();
        for (int i=0; i<NUM_DATA_POINTS; i++) {
            Data<Number, Number> dataPoint = new Data<Number, Number>(i, rng.nextInt(1000));
            series.getData().add(dataPoint);
        }
        return FXCollections.observableArrayList(Collections.singleton(series));
    }

    private void setUpZooming(final Rectangle rect, final Node zoomingNode) {
        final ObjectProperty<Point2D> mouseAnchor = new SimpleObjectProperty<>();
        zoomingNode.setOnMousePressed(new EventHandler<MouseEvent>() {
            @Override
            public void handle(MouseEvent event) {
                mouseAnchor.set(new Point2D(event.getX(), event.getY()));
                rect.setWidth(0);
                rect.setHeight(0);
            }
        });
        zoomingNode.setOnMouseDragged(new EventHandler<MouseEvent>() {
            @Override
            public void handle(MouseEvent event) {
                double x = event.getX();
                double y = event.getY();
                rect.setX(Math.min(x, mouseAnchor.get().getX()));
                rect.setY(Math.min(y, mouseAnchor.get().getY()));
                rect.setWidth(Math.abs(x - mouseAnchor.get().getX()));
                rect.setHeight(Math.abs(y - mouseAnchor.get().getY()));
            }
        });
    }

    private void doZoom(Rectangle zoomRect, LineChart<Number, Number> chart) {
        Point2D zoomTopLeft = new Point2D(zoomRect.getX(), zoomRect.getY());
        Point2D zoomBottomRight = new Point2D(zoomRect.getX() + zoomRect.getWidth(), zoomRect.getY() + zoomRect.getHeight());
        final NumberAxis yAxis = (NumberAxis) chart.getYAxis();
        Point2D yAxisInScene = yAxis.localToScene(0, 0);
        final NumberAxis xAxis = (NumberAxis) chart.getXAxis();
        Point2D xAxisInScene = xAxis.localToScene(0, 0);
        double xOffset = zoomTopLeft.getX() - yAxisInScene.getX() ;
        double yOffset = zoomBottomRight.getY() - xAxisInScene.getY();
        double xAxisScale = xAxis.getScale();
        double yAxisScale = yAxis.getScale();
        xAxis.setLowerBound(xAxis.getLowerBound() + xOffset / xAxisScale);
        xAxis.setUpperBound(xAxis.getLowerBound() + zoomRect.getWidth() / xAxisScale);
        yAxis.setLowerBound(yAxis.getLowerBound() + yOffset / yAxisScale);
        yAxis.setUpperBound(yAxis.getLowerBound() - zoomRect.getHeight() / yAxisScale);
        System.out.println(yAxis.getLowerBound() + " " + yAxis.getUpperBound());
        zoomRect.setWidth(0);
        zoomRect.setHeight(0);
    }

    public static void main(String[] args) {
        launch(args);
    }
}

在下面转换为JavaFXML App时：

FXMLDocument

<?xml version="1.0" encoding="UTF-8"?>

<?import javafx.scene.chart.*?>
<?import java.lang.*?>
<?import java.util.*?>
<?import javafx.scene.*?>
<?import javafx.scene.control.*?>
<?import javafx.scene.layout.*?>

<AnchorPane id="AnchorPane" prefHeight="525.0" prefWidth="619.0" xmlns:fx="http://javafx.com/fxml/1" xmlns="http://javafx.com/javafx/8" fx:controller="javafxapplication24.FXMLDocumentController">
   <children>
      <LineChart fx:id="lineChart" layoutX="71.0" layoutY="63.0" prefHeight="322.0" prefWidth="484.0">
        <xAxis>
          <CategoryAxis side="BOTTOM" />
        </xAxis>
        <yAxis>
          <NumberAxis side="LEFT" />
        </yAxis>
      </LineChart>
      <StackPane fx:id="chartContainer" layoutX="100.0" layoutY="74.0" prefHeight="289.0" prefWidth="453.0" />
      <Button fx:id="zoomButton" layoutX="191.0" layoutY="411.0" mnemonicParsing="false" text="Zoom" />
      <Button fx:id="resetButton" layoutX="275.0" layoutY="411.0" mnemonicParsing="false" text="Reset" />
      <BorderPane fx:id="root" prefHeight="507.0" prefWidth="607.0" />
   </children>
</AnchorPane>

JavaFXApplication

   package javafxapplication24;

import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;

public class JavaFXApplication24 extends Application {

    @Override
    public void start(Stage stage) throws Exception {
        Parent root = FXMLLoader.load(getClass().getResource("FXMLDocument.fxml"));

        Scene scene = new Scene(root);

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

    public static void main(String[] args) {
        launch(args);
    }

}

FXMLDocumentController

    package javafxapplication24;

import java.net.URL;
import java.util.ResourceBundle;
import javafx.beans.binding.BooleanBinding;
import javafx.beans.property.ObjectProperty;
import javafx.beans.property.SimpleObjectProperty;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.geometry.Insets;
import javafx.geometry.Point2D;
import javafx.geometry.Pos;
import javafx.scene.Node;
import javafx.scene.chart.LineChart;
import javafx.scene.chart.NumberAxis;
import javafx.scene.chart.XYChart;
import javafx.scene.control.Button;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.HBox;
import javafx.scene.layout.StackPane;
import javafx.scene.paint.Color;
import javafx.scene.shape.Rectangle;


public class FXMLDocumentController implements Initializable {

    @FXML
    private LineChart lineChart;
    @FXML
    private StackPane chartContainer;
    @FXML
    private Button zoomButton;
    @FXML
    private Button resetButton;
    @FXML
    private BorderPane root;


    @Override
    public void initialize(URL url, ResourceBundle rb) {
        //Code for the Line Graph
        createGraph(lineChart);

        //Set up Zoom rectangle
    chartContainer.getChildren().add(lineChart);
    final Rectangle zoomRect = new Rectangle();
    zoomRect.setManaged(false);
    zoomRect.setFill(Color.LIGHTSEAGREEN.deriveColor(0, 1, 1, 0.5));
    chartContainer.getChildren().add(zoomRect);

    setUpZooming(zoomRect, lineChart);

    final HBox controls = new HBox(2);
    controls.setPadding(new Insets(2));
    controls.setAlignment(Pos.CENTER);


        zoomButton.setOnAction(new EventHandler<ActionEvent>() {
            @Override
            public void handle(ActionEvent event) {
                doZoom(zoomRect, lineChart);
            }
        });

        resetButton.setOnAction(new EventHandler<ActionEvent>() {            
            @Override
            public void handle(ActionEvent event) {
                final NumberAxis xAxis = (NumberAxis)lineChart.getXAxis();
                xAxis.setLowerBound(0);
                xAxis.setUpperBound(1000);
                final NumberAxis yAxis = (NumberAxis)lineChart.getYAxis();
                yAxis.setLowerBound(0);
                yAxis.setUpperBound(1000);

                zoomRect.setWidth(0);
                zoomRect.setHeight(0);
            }
        });

        final BooleanBinding disableControls = 
                zoomRect.widthProperty().lessThan(5)
                .or(zoomRect.heightProperty().lessThan(5));
        zoomButton.disableProperty().bind(disableControls);
        controls.getChildren().addAll(zoomButton, resetButton);

        root.setCenter(chartContainer);
        root.setBottom(controls);
    } 

    //Method for creating the Line Graph
    public void createGraph(LineChart<Number,Number> p) {

        //Code for the Line Graph
        p.getXAxis().setAutoRanging(true);
        p.getYAxis().setAutoRanging(true);

        XYChart.Series series = new XYChart.Series<>();
        series.getData().add(new XYChart.Data<>("Jan", 23));
        series.getData().add(new XYChart.Data("feb", 2));
        series.getData().add(new XYChart.Data("March", 2));
        p.setStyle(".default-color0.chart-series-line { -fx-stroke: brown;   }");

        XYChart.Series series2 = new XYChart.Series<>();
        series2.getData().add(new XYChart.Data<>("Oct", 53));
        series2.getData().add(new XYChart.Data("Nov", 32));
        series2.getData().add(new XYChart.Data("Dec", 32));
        p.setStyle(".default-color0.series2 { -fx-stroke: blue; }");

        p.getData().addAll(series,series2);   
    }   

    private void setUpZooming(final Rectangle rect, final Node zoomingNode) {
        final ObjectProperty<Point2D> mouseAnchor = new SimpleObjectProperty<>();
        zoomingNode.setOnMousePressed(new EventHandler<MouseEvent>() {
            @Override
            public void handle(MouseEvent event) {
                mouseAnchor.set(new Point2D(event.getX(), event.getY()));
                rect.setWidth(0);
                rect.setHeight(0);
            }
        });
        zoomingNode.setOnMouseDragged(new EventHandler<MouseEvent>() {
            @Override
            public void handle(MouseEvent event) {
                double x = event.getX();
                double y = event.getY();
                rect.setX(Math.min(x, mouseAnchor.get().getX()));
                rect.setY(Math.min(y, mouseAnchor.get().getY()));
                rect.setWidth(Math.abs(x - mouseAnchor.get().getX()));
                rect.setHeight(Math.abs(y - mouseAnchor.get().getY()));
            }
        });
    }

    private void doZoom(Rectangle zoomRect, LineChart<Number, Number> chart) {
        Point2D zoomTopLeft = new Point2D(zoomRect.getX(), zoomRect.getY());
        Point2D zoomBottomRight = new Point2D(zoomRect.getX() + zoomRect.getWidth(), zoomRect.getY() + zoomRect.getHeight());
        final NumberAxis yAxis = (NumberAxis) chart.getYAxis();
        Point2D yAxisInScene = yAxis.localToScene(0, 0);
        final NumberAxis xAxis = (NumberAxis) chart.getXAxis();
        Point2D xAxisInScene = xAxis.localToScene(0, 0);
        double xOffset = zoomTopLeft.getX() - yAxisInScene.getX() ;
        double yOffset = zoomBottomRight.getY() - xAxisInScene.getY();
        double xAxisScale = xAxis.getScale();
        double yAxisScale = yAxis.getScale();
        xAxis.setLowerBound(xAxis.getLowerBound() + xOffset / xAxisScale);
        xAxis.setUpperBound(xAxis.getLowerBound() + zoomRect.getWidth() / xAxisScale);
        yAxis.setLowerBound(yAxis.getLowerBound() + yOffset / yAxisScale);
        yAxis.setUpperBound(yAxis.getLowerBound() - zoomRect.getHeight() / yAxisScale);
        System.out.println(yAxis.getLowerBound() + " " + yAxis.getUpperBound());

        zoomRect.setWidth(0);
        zoomRect.setHeight(0);
    }   
}

发现异常：

Exception in thread "JavaFX Application Thread" java.lang.ClassCastException: javafx.scene.chart.CategoryAxis cannot be cast to javafx.scene.chart.NumberAxis
at javafxapplication24.FXMLDocumentController.doZoom(FXMLDocumentController.java:176)
at javafxapplication24.FXMLDocumentController.access$100(FXMLDocumentController.java:38)
at javafxapplication24.FXMLDocumentController$1.handle(FXMLDocumentController.java:83)
at javafxapplication24.FXMLDocumentController$1.handle(FXMLDocumentController.java:80)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:49)
at javafx.event.Event.fireEvent(Event.java:198)
at javafx.scene.Node.fireEvent(Node.java:8411)
at javafx.scene.control.Button.fire(Button.java:185)
at com.sun.javafx.scene.control.behavior.ButtonBehavior.mouseReleased(ButtonBehavior.java:182)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase$1.handle(BehaviorSkinBase.java:96)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase$1.handle(BehaviorSkinBase.java:89)
at com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(CompositeEventHandler.java:218)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:80)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
at javafx.event.Event.fireEvent(Event.java:198)
at javafx.scene.Scene$MouseHandler.process(Scene.java:3757)
at javafx.scene.Scene$MouseHandler.access$1500(Scene.java:3485)
at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1762)
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2494)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:380)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:294)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent$354(GlassViewEventHandler.java:416)
at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:389)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:415)
at com.sun.glass.ui.View.handleMouseEvent(View.java:555)
at com.sun.glass.ui.View.notifyMouse(View.java:937)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$null$148(WinApplication.java:191)
at java.lang.Thread.run(Thread.java:745)

感谢您的帮助。