How to return value from a stage before closing it?

Question

First of all, sorry for the bad english.

Here is the case:

I have a \"main stage\" where i press a button to open a \"second stage\" where i have a table, th

Answer 1

In my main controller I create Stage. Load controller which I can use like any class. And by creating an event I can get data just before closing the window.

try {
        FXMLLoader loader = new FXMLLoader();
        loader.setLocation(getClass().getResource("/package/mySceneBuilderWindow.fxml"));
        final Pane rootPane = (Pane)loader.load();
        Scene scene =  new Scene(rootPane);

        Stage stage = new Stage();
        stage.setTitle("Optional title");
        stage.setScene(scene);

        mySceneBuilderWindowController controller = loader.<mySceneBuilderWindowController>getController();
        controller.iCanSendDataToCtrl("String for now"); // sending data or init textFields...

        stage.show();

        /* set event which is fired on close
            // How to close in the other window... (pressing X is OK too)
                @FXML private Button fxidSave = new Button(); // global var
                @FXML private void handleSaveButton() {
                    Stage stage = (Stage) fxidSave.getScene().getWindow();
                    stage.close(); // closes window
                }
         */
        stage.setOnCloseRequest((EventHandler<WindowEvent>) new EventHandler<WindowEvent>() {
            public void handle(WindowEvent we) {
                String iCanGetDataBeforeClose = controller.getData();
                System.out.println(iCanGetDataBeforeClose);
                // static class can be used aswell -> System.out.println(Context.getMyString());
            }
        });

    } catch (IOException e) {
        System.out.println("something wrong with .fxml - name wrong? path wrong? building error?");
    }  

My other mySceneBuilderWindowController methods:

 public void iCanSendDataToCtrl(String giveMe) {
    // do something ex. myTextBox.setText(giveMe);
 }
 public String iCanGetDataBeforeClose() {
    // do something ex. return myTextBox.getText();
 }

Answer 2

Here is a possible example. The structure is the same as in the answer in my comment.

The second Stage is opened through a "controller" that is stores the data that should be returned even when the Stage is closed and exposes a getter to be used to retrieve the value from the outer world.

import javafx.application.Application;
import javafx.stage.Modality;
import javafx.stage.Stage;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.TextField;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.VBox;


public class Main extends Application {

    @Override
    public void start(Stage primaryStage) {
        try {
            BorderPane root = new BorderPane();
            Scene scene = new Scene(root,400,400);

            Button bSecondStage = new Button("Show second Stage");
            bSecondStage.setOnAction(e -> {
                WindowController wc = new WindowController();
                wc.showStage();
                System.out.println(wc.getData());
            });

            root.setCenter(bSecondStage);


            primaryStage.setScene(scene);
            primaryStage.show();
        } catch(Exception e) {
            e.printStackTrace();
        }
    }

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

    class WindowController {
        private String data;

        void showStage() {
            Stage stage = new Stage();
            stage.initModality(Modality.APPLICATION_MODAL);

            VBox root = new VBox();
            Scene scene = new Scene(root);
            TextField tf = new TextField();
            Button submit = new Button("Submit");

            submit.setOnAction(e -> {
                data = tf.getText();
                stage.close();
            });

            root.getChildren().addAll(tf, submit);
            stage.setScene(scene);
            stage.showAndWait();
        }

        String getData() {
            return data;
        }
    }
}

Answer 3

You can write your own Stage class with a return statement.

public class MyStage extends Stage {
   public String showAndReturn(myFXControll controll) {     
      super.showAndWait();
      return controll.getReturn();
   }
} 

After that you have to define a return function to your controller.

public class TableFilterControll implements Initializable {
    @Override
    public void initialize(URL arg0, ResourceBundle arg1) {
    }
    public String getReturn() {
        return "I'm a nice return value"; //return what you want controlled by your controller class
    }
}

Now you can controll your return from the parent controller.

String retValue=myStage.showAndReturn(childControll);

System.out.println(retValue);

I think this is a good solution for clean code. And you can style your FXML with Screne Builder.

Answer 4

There is some error in 4baad4's example. If the method in the controller is iCanGetDataBeforeClose, then that's what should be called:

String someValue = controller.iCanGetDataBeforeClose();

But even that didn't work right for me. I actually got this to work without using setOnCloseRequest at all. In the form controller, I had a method like this:

public boolean getCompleted() {
    return this.finished;
}

Then in the form calling it:

FXMLLoader loader = new FXMLLoader();
loader.setLocation(getClass().getResource("myView.fxml"));
AnchorPane pane = (AnchorPane) loader.load();
myViewController controller = loader.getController();
Scene scene = new Scene(pane);
Stage stage = new Stage();
stage.setScene(scene);
stage.showAndWait();
if (controller.getCompleted()){
    doStuff();
}

One might think that since the stage had exited that the controller would throw a null reference exception, but it didn't, and it returned the correct response.

This solution works and is simplest proposed IMHO.