Error in JavaFX FXML tutorial

Question

I have followed every step in this (https://blogs.oracle.com/jmxetc/entry/connecting_scenebuilder_edited_fxml_to) tutorial, and yet keep getting an error about this section in the controller class:

    myButton.setOnAction(new EventHandler<ActionEvent>() {

        @Override
        public void handle(ActionEvent event) {
            System.out.println("That was easy, wasn't it?");
        }
    });

The only difference I can think of is that it was written for FX 2.0 and not 8.0?

Exception in Application start method
java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    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(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at sun.launcher.LauncherHelper$FXHelper.main(LauncherHelper.java:767)
Caused by: java.lang.RuntimeException: Exception in Application start method
    at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:917)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication$155(LauncherImpl.java:182)
    at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.Error: Unresolved compilation problems: 
    The method setOnAction(EventHandler<ActionEvent>) in the type ButtonBase is not applicable for the arguments (new EventHandler<ActionEvent>(){})
    EventHandler cannot be resolved to a type
    The method handle(ActionEvent) of type new EventHandler<ActionEvent>(){} must override or implement a supertype method

    at simple.SimpleController.initialize(SimpleController.java:24)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2548)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2441)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3214)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3175)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3148)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3124)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3104)
    at javafx.fxml.FXMLLoader.load(FXMLLoader.java:3097)
    at simple.Main.start(Main.java:26)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$162(LauncherImpl.java:863)
    at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$175(PlatformImpl.java:326)
    at com.sun.javafx.application.PlatformImpl.lambda$null$173(PlatformImpl.java:295)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.application.PlatformImpl.lambda$runLater$174(PlatformImpl.java:294)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
Exception running application simple.Main

Let me know if you need to see the classes and FXML files (dw, they're very short)

Thank you!

PS- Please bear with me if I need clarification about your answer because as a Java newbie I often get confused!

EDIT 1:

package simple;

import java.net.URL;
import java.util.ResourceBundle;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.Button;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;


public class SimpleController
    implements Initializable {

    @FXML //  fx:id="myButton"
    private Button myButton; // Value injected by FXMLLoader


    @Override // This method is called by the FXMLLoader when initialization is complete
    public void initialize(URL fxmlFileLocation, ResourceBundle resources) {
        assert myButton != null : "fx:id=\"myButton\" was not injected: check your FXML file 'simple.fxml'.";

        // initialize your logic here: all @FXML variables will have been injected
        myButton.setOnAction(new EventHandler<ActionEvent>() {

            @Override
            public void handle(ActionEvent event) {
                System.out.println("That was easy, wasn't it?");
            }
        });
    }

}

It says you have a compile error, with EventHandler not being recognized. Please post the SimpleController source code (including imports). — James_D
– James_D, Commented Jan 19, 2016 at 16:06
There are several classes named EventHandler and ActionEvent, show us which ones you are importing. — greg-449
– greg-449, Commented Jan 19, 2016 at 16:10
(I'm not sure if you get updated when I edit the question so here! notification!) Thank you so much for looking at this I'm very grateful — a-joyce
– a-joyce, Commented Jan 19, 2016 at 16:11

James_D · Accepted Answer · 2016-01-19 16:12:42Z

1

You are missing the import for EventHandler, and you have the wrong import for ActionEvent. (Also you have imported ActionListener for some reason, though you never use it.)

Your imports should be

import java.net.URL;
import java.util.ResourceBundle;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.Button;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;

answered Jan 19, 2016 at 16:12

James_D

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1 Comment

a-joyce Over a year ago

I know it says to avoid +1 comments, but seriously thank you good sir

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