Ich habe folgenden Code:

package pl.javastart.youtufy.controller;

import java.net.URL;
import java.util.ResourceBundle;

import javafx.application.Platform;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.Node;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.ToggleButton;
import javafx.scene.web.WebEngine;
import javafx.stage.Stage;

public class ConnectionErrorController implements Initializable {

    @FXML
    private Label infoLabel;

    @FXML
    private Button tryButton;

    @FXML
    private Button exitButton;


    @Override
    public void initialize(URL location, ResourceBundle resources) {

        MainController mc = new MainController();

        infoLabel.setText("Connection lost, please try again");
        tryButton.setText("try again");
        exitButton.setText("exit");

        tryButton.setOnAction(new EventHandler<ActionEvent>() {
            @Override
            public void handle(ActionEvent event) {

                WebEngine webEngine = mc.getContentPaneController().getVideoWebView().getEngine(); // 1
                ToggleButton playButton = mc.getControlPaneController().getPlayButton(); // 2
                Node source = (Node) event.getSource();
                Stage stage = (Stage) source.getScene().getWindow();
                if (mc.testInet()) {
                    stage.close();
                    mc.play(webEngine, playButton);
                } else {
                    stage.close();
                    MainController.exist = false;
                }
            }
        });

        exitButton.setOnAction(new EventHandler<ActionEvent>() {
            @Override
            public void handle(ActionEvent event) {
                Platform.exit();
            }
        });
    }

}

Ich versuche, WebEngine- und ToggleButton-Objekte von Controllern in MainController zu verwenden (ich habe Getter und Setter für sie in MainController generiert):

public class MainController implements Initializable {

@FXML
private ContentPaneController contentPaneController;

@FXML
private ControlPaneController controlPaneController;

@FXML
private MenuPaneController menuPaneController;

@FXML
private SearchPaneController searchPaneController;

private Youtube youtubeInstance;

public static boolean exist = false;

public ControlPaneController getControlPaneController() {
    return controlPaneController;
}

public void setControlPaneController(ControlPaneController controlPaneController) {
    this.controlPaneController = controlPaneController;
}

public ContentPaneController getContentPaneController() {
    return contentPaneController;
}

public void setContentPaneController(ContentPaneController contentPaneController) {
    this.contentPaneController = contentPaneController;
}

Aber es gibt immer noch NullPointerException zurück. Ich hatte das gleiche Problem, als ich versuchte, einfach Verweise auf die Controller in ConnectionErrorController zu erstellen. Wie kann ich in ConnectionErrorController ordnungsgemäß auf ToggleButton i-WebEngine-Objekte von Controllern verweisen? Grüß