JavaFX中的显示图表

Question

我试图重写和简化图表的oracle教程，以便您拥有控制器类并使用fxml。 由于某种原因，它无法正常工作。

这里是我的代码： 主类：

public class BarChartSample extends Application { 

    Stage primaryStage; 

    public void start(Stage primaryStage) { 
     this.primaryStage = primaryStage; 
     primaryStage.setTitle("Bar Chart Sample"); 

     showPage(); 
    } 

    public void showPage(){ 
     try { 
      FXMLLoader loader = new FXMLLoader(); 
     loader.setLocation(BarChartSample.class.getResource("ChartPage.fxml")); 
      AnchorPane pane = loader.load(); 

      Scene scene = new Scene(pane); 
      primaryStage.setScene(scene); 
      primaryStage.show(); 
     } catch (Exception e) { 
      e.printStackTrace(); 
     } 
    } 

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

控制器：

public class Controller { 
    final static String performance = "Performance:"; 

    @FXML 
    NumberAxis xAxis = new NumberAxis(); 
    @FXML 
    CategoryAxis yAxis = new CategoryAxis(); 

    @FXML 
    BarChart<Number,String> bc; 

    public void initialize(){ 
     xAxis.setLabel("Percent"); 
     xAxis.setTickLabelRotation(90); 
     yAxis.setLabel("Performance"); 

     bc = new BarChart<Number,String>(xAxis,yAxis); 

     XYChart.Series series1 = new XYChart.Series();  
     series1.getData().add(new XYChart.Data(80, performance)); 
     bc.getData().add(series1); 
    } 
} 

FXML：

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

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

<AnchorPane prefHeight="393.0" prefWidth="419.0" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1" fx:controller="Controller"> 
    <children> 
     <BarChart fx:id="bc" layoutX="-40.0" layoutY="-3.0" prefHeight="205.0" prefWidth="409.0" AnchorPane.bottomAnchor="5.0" AnchorPane.leftAnchor="5.0" AnchorPane.rightAnchor="5.0"> 
     <xAxis> 
      <CategoryAxis fx:id="yAxis" side="BOTTOM" /> 
     </xAxis> 
     <yAxis> 
      <NumberAxis side="LEFT" fx:id="xAxis" /> 
     </yAxis> 
     </BarChart> 
    <TextArea layoutX="103.0" layoutY="14.0" maxHeight="100.0" prefHeight="200.0" prefWidth="200.0" AnchorPane.leftAnchor="21.0"AnchorPane.rightAnchor="21.0" AnchorPane.topAnchor="5.0" /> 
     </children> 
     </AnchorPane> 

将不能正常显示图表，它只是画几行。为什么？谢谢！

Answer 1

从initialize()

bc = new BarChart<Number,String>(xAxis,yAxis); 

你不应该重新初始化它已经在FXML定义，并已通过@FXML注释集成在控制器的任何控制删除此行。

您还需要与

@FXML 
NumberAxis xAxis; 
@FXML 
CategoryAxis yAxis; 

替换下列行的原因说

@FXML 
NumberAxis xAxis = new NumberAxis(); 
@FXML 
CategoryAxis yAxis = new CategoryAxis(); 

同样，你需要正确定义BARCHART。在FXML中，您宣称xAxis为CategoryAxis和yAxis为NumberAxis。但是在控制器中你定义了一个BarChart<Number,String>。

public class Controller { 
    final static String performance = "Performance:"; 

    @FXML 
    NumberAxis xAxis; 
    @FXML 
    CategoryAxis yAxis; 

    @FXML 
    BarChart<String, Number> bc; 

    public void initialize(){ 
     xAxis.setLabel("Percent"); 
     xAxis.setTickLabelRotation(90); 
     yAxis.setLabel("Performance"); 

     XYChart.Series<String, Number> series1 = new XYChart.Series(); 
     series1.getData().add(new XYChart.Data(performance, 80)); 
     bc.getData().add(series1); 
    } 
}