How to set Axis range in Java FX using SampleController?

Question

I created a fxml layout using the builder v2.0 script. I am changing the diagram in the ie controller file, SampleController.java. I was able to set the name of the chart using the .setTitle method. I need to set the range of xAxis (Start, End, Ticks) and yAxis dynamically. CSS is easy to set using the lowerBound and upperBound properties. But this is a permanent solution. Please provide your valuable suggestions and solutions.

Main.java:

package application; import javafx.application.Application; import javafx.fxml.FXMLLoader; import javafx.scene.Scene; import javafx.scene.control.SplitPane; import javafx.stage.Stage; public class Main extends Application{ @Override public void start(Stage primaryStage) { try { SplitPane root = (SplitPane)FXMLLoader.load(getClass().getResource("Sample.fxml")); Scene scene = new Scene(root,800,400); scene.getStylesheets().add(getClass().getResource("application.css").toExternalForm()); primaryStage.setScene(scene); primaryStage.show(); } catch(Exception e) { e.printStackTrace(); } } public static void main(String[] args) { launch(args); } } 

Sample.fxml

 <?xml version="1.0" encoding="UTF-8"?> <?import javafx.scene.control.*?> <?import java.lang.*?> <?import javafx.scene.chart.*?> <?import javafx.scene.layout.*?> <?import javafx.scene.layout.BorderPane?> <SplitPane dividerPositions="0.7892976588628763" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="400.0" minWidth="800.0" prefHeight="400.0" prefWidth="800.0" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1" fx:controller="application.SampleController"> <items> <AnchorPane minHeight="0.0" minWidth="0.0" prefHeight="160.0" prefWidth="100.0"> <children> <LineChart fx:id="Ch" alternativeColumnFillVisible="true" layoutX="14.0" prefHeight="398.0" prefWidth="500.0"> <xAxis> <NumberAxis side="BOTTOM" /> </xAxis> <yAxis> <NumberAxis layoutX="10.0" side="LEFT" /> </yAxis> </LineChart> </children></AnchorPane> <AnchorPane minHeight="0.0" minWidth="0.0" prefHeight="160.0" prefWidth="100.0"> <children> <Button fx:id="sine" layoutX="21.0" layoutY="101.0" mnemonicParsing="false" text="Sinusoidal" /> <Button fx:id="triangle" layoutX="21.0" layoutY="148.0" mnemonicParsing="false" prefHeight="25.0" prefWidth="70.0" text="Triangle" /> <Button fx:id="square" layoutX="21.0" layoutY="187.0" mnemonicParsing="false" prefHeight="25.0" prefWidth="70.0" text="Square" /> <Label layoutX="20.0" layoutY="40.0" prefHeight="17.0" prefWidth="83.0" text="Controls" /> </children></AnchorPane> </items> </SplitPane> 

SampleController.java

 package application; import java.net.URL; import java.util.ResourceBundle; import javafx.animation.Animation; import javafx.animation.KeyFrame; import javafx.animation.Timeline; import javafx.collections.FXCollections; import javafx.collections.ObservableList; import javafx.event.ActionEvent; import javafx.event.EventHandler; import javafx.fxml.FXML; import javafx.fxml.Initializable; import javafx.scene.chart.Axis; import javafx.scene.chart.LineChart; import javafx.scene.chart.NumberAxis; import javafx.scene.chart.XYChart; import javafx.scene.chart.XYChart.Series; import javafx.scene.control.Button; import javafx.util.Duration; public class SampleController implements Initializable { final NumberAxis xAxis = new NumberAxis(0,24,3); final NumberAxis yAxis = new NumberAxis(0,1,0.1); @FXML // fx:id="Ch" private LineChart<Number, Number> Ch= new LineChart<>(xAxis, yAxis); // No use of using a constructor. @FXML// fx:id="sine" private Button sine; // Value injected by FXMLLoader @FXML// fx:id="triangle" private Button triangle; // Value injected by FXMLLoader @FXML// fx:id="Square" private Button square; // Value injected by FXMLLoader @Override // This method is called by the FXMLLoader when initialization is complete public void initialize(URL fxmlFileLocation, ResourceBundle resources) { assert Ch != null : "fx:id=\"Ch\" was not injected: check your FXML file 'sample.fxml'."; // initialize your logic here: all @FXML variables will have been injected sine.setOnAction(new EventHandler<ActionEvent>() { @Override public void handle(ActionEvent event) { System.out.println("Sinusoidal Signal Selected /n/n"); } }); triangle.setOnAction(new EventHandler<ActionEvent>() { @Override public void handle(ActionEvent event) { System.out.println("Triangle Signal Selected /n/n"); } }); square.setOnAction(new EventHandler<ActionEvent>() { @Override public void handle(ActionEvent event) { System.out.println("Square Signal Selected /n/n"); } }); //Ch = new LineChart<>(xAxis, yAxis); // This sadly loads a new chart but is not visible Ch.setTitle("PiScope Demo"); //Need to set xAxis range Dynamically //Need to set yAxis range Dynamically /* * In CSS we can use lowerBound and upperBound Property. * */ } } 

Answer 1

Enter the axis in the controller:

  <LineChart fx:id="Ch" alternativeColumnFillVisible="true" layoutX="14.0" prefHeight="398.0" prefWidth="500.0"> <xAxis> <NumberAxis side="BOTTOM" fx:id="xAxis" /> </xAxis> <yAxis> <NumberAxis layoutX="10.0" side="LEFT" fx:id="yAxis" /> </yAxis> </LineChart> 

and

 public class SampleController implements Initializable { @FXML private NumberAxis xAxis ; @FXML private NumberAxis yAxis ; // never initialize fields that are injected by @FXML: // they are initialized by the FXMLLoader @FXML // fx:id="Ch" private LineChart<Number, Number> Ch ; // ... } 

Then you can simply set the range in the initialize() method:

 public void initialize() { // ... xAxis.setAutoRanging(false); xAxis.setLowerBound(0); xAxis.setUpperBound(24); xAxis.setTickUnit(3); yAxis.setAutoRanging(false); yAxis.setLowerBound(0); yAxis.setUpperBound(1); yAxis.setTickUnit(0.1); // ... } 

Answer 2

There are several “axis” options related to the javafx chart. I found that initializing LineChart in fxml led to Axis <Number>. The <T> axis has no defined methods for the lower and upper bounds. So I found a solution by explicitly pointing to NumberAxis, which has these given methods.

 public void setAxisBounds(LineChart<Number, Number> myChart, double min, double max, boolean isXAxis) { NumberAxis axis; if (isXAxis) axis=(NumberAxis) myChart.getXAxis(); else axis=(NumberAxis) myChart.getYAxis(); axis.setAutoRanging(false); axis.setLowerBound(min); axis.setUpperBound(max); }