Starting off with JavaFX : Can not set javafx.scene.control.Label field application.SceneController.myLabel to javafx.scene.text.Text

Question

I'm starting off with JavaFX.

The error occurs when I execute my program, before I attempted to do this, it worked fine and button clicks worked, but that was before it was my intention to make the button click change the text.

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

<AnchorPane xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1" fx:controller="application.SceneController">
   <children>
      <AnchorPane layoutX="-100.0" layoutY="-224.0" prefHeight="572.0" prefWidth="430.0">
         <children>
            <Button layoutX="205.0" layoutY="253.0" mnemonicParsing="false" onAction="#handleActionButton1" text="Do you want swag?" />
            <Text fx:id="myLabel" layoutX="280.0" layoutY="339.0" strokeType="OUTSIDE" strokeWidth="0.0" text="My text will change!" />
         </children>
      </AnchorPane>
   </children>
</AnchorPane>

That's the FXML, on the line, you can see the text is "My text will change!". On Eclipse's FXML text editor it gives me this error : "You can not assign 'Text' to the controller field 'Label'".

This is my SceneController class:

package application;

import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.scene.control.Label;

public class SceneController{

    @FXML
    private Label myLabel;

    @FXML
    public void handleActionButton1(ActionEvent event){
        System.out.println("Hello World!");
        myLabel.setText("Hello World!");
    }

}

As I mentioned above, before I had a label, it would successfully output "Hello World" on the console, but now it does that, but doesn't execute my Java application and it gives me a long error:

javafx.fxml.LoadException: 
/C:/Users/Neil/development/JavaFX/bin/application/appfxml.fxml:14

    at javafx.fxml.FXMLLoader.constructLoadException(Unknown Source)
    at javafx.fxml.FXMLLoader.loadImpl(Unknown Source)
    at javafx.fxml.FXMLLoader.loadImpl(Unknown Source)
    at javafx.fxml.FXMLLoader.load(Unknown Source)
    at application.Main.start(Main.java:15)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$153(Unknown Source)
    at com.sun.javafx.application.LauncherImpl$$Lambda$51/1299755900.run(Unknown Source)
    at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$166(Unknown Source)
    at com.sun.javafx.application.PlatformImpl$$Lambda$45/1051754451.run(Unknown Source)
    at com.sun.javafx.application.PlatformImpl.lambda$null$164(Unknown Source)
    at com.sun.javafx.application.PlatformImpl$$Lambda$47/1698159280.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.application.PlatformImpl.lambda$runLater$165(Unknown Source)
    at com.sun.javafx.application.PlatformImpl$$Lambda$46/1775282465.run(Unknown Source)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(Unknown Source)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$141(Unknown Source)
    at com.sun.glass.ui.win.WinApplication$$Lambda$37/1109371569.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.IllegalArgumentException: Can not set javafx.scene.control.Label field application.SceneController.myLabel to javafx.scene.text.Text
    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(Unknown Source)

Answer 1

Inside your FXML, you have defined a Text, where as in your Controller, you are trying to use it as Label.

The stackTrace (error) is shouting it on the top of its voice :

Can not set javafx.scene.control.Label field application.SceneController.myLabel to javafx.scene.text.Text

In your controller, you need to change the myLabel definition to

@FXML
private Text myLabel;