[Résolu] [JAVAFX] Appelle d'une méthode par GrenouilleSmall - page 1

Bonjour, je créer une application avec javafx et FXML mais je me confronte à un problème :

Lorsque j'appelle une méthode qui est dans le controlleur de mon fxml à partir d'une autre classe on me retourne un Java.NullPointerException.

Voici mon controlleur :

package main;

import javafx.fxml.FXML;
import javafx.fxml.FXMLLoader;
import javafx.fxml.Initializable;
import javafx.scene.control.Button;
import javafx.scene.layout.VBox;

import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.util.ResourceBundle;

public class Home_Controller implements Initializable {
    @FXML
    VBox section;

    /**
     * Called to initialize a controller after its root element has been
     * completely processed.
     *
     * @param location  The location used to resolve relative paths for the root object, or
     *                  <tt>null</tt> if the location is not known.
     * @param resources The resources used to localize the root object, or <tt>null</tt> if
     */
    @Override
    public void initialize(URL location, ResourceBundle resources) {
        File dir = new File("src/Resources");
        for (File dur : dir.listFiles()){
            File[] files = dur.listFiles((dir1, name) -> name.toLowerCase().endsWith(".fxml"));
            assert files != null;
            for (File file : files){
                try {
                    URL url = new File(file.getAbsolutePath()).toURI().toURL();
                    System.out.println(url.getPath());
                    Button boutton = FXMLLoader.load(url);
                    section.getChildren().add(boutton);
                } catch (IOException e) {e.printStackTrace();}
            }
        }
    }

public void getB (){
        Button a = new Button ();
        section.getChildren().add(a);
}
}

Mon fichier fxml :

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

<?import javafx.scene.control.*?>
<?import javafx.scene.layout.*?>

<AnchorPane maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="400.0" prefWidth="600.0" xmlns="http://javafx.com/javafx/10.0.2-internal" xmlns:fx="http://javafx.com/fxml/1" fx:controller="main.Home_Controller">
   <children>
      <SplitPane dividerPositions="0.3311036789297659" prefHeight="400.0" prefWidth="600.0">
        <items>
          <AnchorPane minHeight="0.0" minWidth="0.0" prefHeight="398.0" prefWidth="198.0">
               <children>
                  <VBox fx:id="section" prefHeight="398.0" prefWidth="195.0">
                     <children>
                        <Button fx:id="test" mnemonicParsing="false" text="Button" />
                     </children>
                  </VBox>
               </children>
            </AnchorPane>
          <AnchorPane fx:id="c" minHeight="0.0" minWidth="0.0" prefHeight="160.0" prefWidth="100.0" />
        </items>
      </SplitPane>
   </children>
</AnchorPane>

Et voici ma classe depuis lequel j'appelle la méthode du controlleur :

package Resources.JV;

import javafx.fxml.FXML;
import javafx.scene.control.Button;
import main.Home_Controller;

public class JV{
    @FXML
    Button button;
    
    public void load () {
        Home_Controller a = new Home_Controller();
        a.getB();
    }
}

Et enfin l'erreur :

Exception in thread "JavaFX Application Thread" java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
	at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1774)
	at javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1657)
	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.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.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$MouseEventNotification.run(GlassViewEventHandler.java:394)
	at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:295)
	at java.security.AccessController.doPrivileged(Native Method)
	at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent$2(GlassViewEventHandler.java:432)
	at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:410)
	at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:431)
	at com.sun.glass.ui.View.handleMouseEvent(View.java:555)
	at com.sun.glass.ui.View.notifyMouse(View.java:937)
	at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
	at com.sun.glass.ui.win.WinApplication.lambda$null$4(WinApplication.java:186)
	at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.reflect.InvocationTargetException
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at sun.reflect.misc.Trampoline.invoke(MethodUtil.java:71)
	at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:275)
	at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1771)
	... 52 more
Caused by: java.lang.NullPointerException
	at main.Home_Controller.getB(Home_Controller.java:51)
	at Resources.JV.JV.load(JV.java:34)
	... 62 more

GrenouilleSmall

24 février 2020 à 19:56:37

Zachee54

25 février 2020 à 14:58:32

Le problème vient de ta méthode load : tu instancies un Home_Controller, mais celui-ci n'est lié à aucune interface graphique. Sa propriété section est null.

Il faut que tu charges ton document FXML depuis ta classe principale JV, et c'est le FXMLLoader qui va instancier pour toi le Home_Controller.
Va voir le tuto officiel ici : https://docs.oracle.com/javase/8/javafx/fxml-tutorial/fxml_tutorial_intermediate.htm

Au passage, ça n'a aucun intérêt de mettre une annotation @FXML dans JV puisque FXML ne va pas la lire dans cette classe.
Enfin, l'objet que tu récupères est celui qui est à la racine de ton fichier fxml, c'est-à-dire un AnchorPane. Pas un Button.

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