java.lang.IllegalStateException: Not on FX application thread Calling Function

Question

Something strange is happening.. Untill 10 minutes ago I had no problem with this code. But now I have a problem updating JUST my VBOX from an external thread.

These are my three classes:

Controller Class:

public class Controller implements Initializable{
@FXML
private VBox slaveVbox;

private ButtonBar newNode = new ButtonBar();
private Circle c= new Circle();
private Button b= new Button();
private Label lname = new Label();
private Label lIMEI = new Label();
private Label lroot = new Label();

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

public void create(String imei, String permission,boolean isOnline) throws IOException{
    if(!alreadyExist(imei)){
    newNode = new ButtonBar();
    b = setButtonSpec(imei + "btnHavefun");
    c = setCircleSpec(imei + "statuOnline", isOnline);
    lname= setLNameSpec(imei + "name");
    lIMEI = setLIMEISpec(imei + "Imei");
    lroot = setLrootSpec(imei + "root", permission);
    newNode.getButtons().addAll(lname,lIMEI,lroot,b,c);
    slaveVbox.getChildren().addAll(newNode);
   }
  }
}

Main Class:

public class MainApp extends Application {
 FXMLLoader loader2;
 private Stage primaryStage;
 private BorderPane rootLayout;

@Override
public void start(Stage primaryStage) throws IOException {
    this.primaryStage = primaryStage;
    this.primaryStage.setTitle("Thypheon Application");
    initRootLayout();
    Controller controller2 = initDesign();
    Connection con = new Connection(controller2);
    Thread t = new Thread(con);
    t.start();

    primaryStage.setOnCloseRequest(new EventHandler<WindowEvent>() {
           @Override
           public void handle(WindowEvent e) {
              Platform.exit();
              System.exit(0);
           }
        });
}

public static void main(String[] args) {
    launch(args);
}

public void initRootLayout(){
    try {
        FXMLLoader loader = new FXMLLoader(getClass().getResource("RootLayout.fxml"));
        rootLayout = (BorderPane) loader.load();
        Scene scene = new Scene(rootLayout);
        primaryStage.setScene(scene);
        primaryStage.show();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

public Controller initDesign(){
    try {
        FXMLLoader loader2= new FXMLLoader(getClass().getResource("Design.fxml"));
        AnchorPane anchor  = (AnchorPane) loader2.load();
        rootLayout.setCenter(anchor);
        Controller controller = loader2.getController();
        return controller;

    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
        return null;
    }

}


public Stage getPrimaryStage(){
    return primaryStage;
}

 }

Connection THREAD:

public class Connection implements Runnable {
 String result;
 Controller controller;

   public Connection(Controller controller) {
       this.controller = controller;
   }

@Override
public void run() {
        try {
            controller.create("jhgjhgjh", "dssf", true);
    } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
 }

Debugging the Application Everything works perfectly untill I reach slaveVbox.getChildren().addAll(newNode); Here comes the exception.. After some attempt to solve the problem I figured out that if I create a ButtonBar and I insert it in the slaveVbox from Main (inside start()) it works fine.. So I ve tied to add controller2.create("FIRST", "FIRST", true); in my start() function like this:

@Override
public void start(Stage primaryStage) throws IOException {
    this.primaryStage = primaryStage;
    this.primaryStage.setTitle("Thypheon Application");
    initRootLayout();
    Controller controller2 = initDesign();
    controller2.create("FIRST", "FIRST", true);
    Connection con = new Connection(controller2);
    Thread t = new Thread(con);
    t.start();

    primaryStage.setOnCloseRequest(new EventHandler<WindowEvent>() {
           @Override
           public void handle(WindowEvent e) {
              Platform.exit();
              System.exit(0);
           }
        });
}

But obviously my application shows two ButtonBars... One created in the start() function and one created inside the Connection Thread.. How Can I avoid this?? Why I can't directly add item inside my VBox directly from my Connecton thread??

James_D · Accepted Answer · 2016-02-13 19:06:39Z

3

You cannot update the UI from a thread other than the FX Application Thread. See, for example, the "Threading" section in the Application documentation.

It's not at all clear why you are using a background thread at all here: there doesn't seem to be any long-running code in the method you are calling. In general, if you have long-running code to call, you can call it in a background thread and then update the UI by wrapping UI update in a Platform.runLater(...).

public class Connection implements Runnable {
  String result;
  Controller controller;

   public Connection(Controller controller) {
       this.controller = controller;
   }

   @Override
   public void run() {
        try {
            // execute long-running code here...

            // perform any updates to the UI on the FX Application Thread:
            Platform.runLater(() -> {
                // code that updates UI
            });

            // more long-running code can go here...

        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
   }
}

answered Feb 13, 2016 at 19:06

James_D

211k16 gold badges312 silver badges345 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Alessio Trecani Over a year ago

Teorically I simplify my code.. But I have a while loop that read data from a socket.. i will try what you advice.. I ll be there soon

Collectives™ on Stack Overflow

java.lang.IllegalStateException: Not on FX application thread Calling Function

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related