import io.reactivex.rxjava3.core.Observable;

import javafx.application.Application;

import javafx.beans.value.ChangeListener;

import javafx.beans.value.ObservableValue;

import javafx.scene.Scene;

import javafx.scene.control.Label;

import javafx.scene.control.ToggleButton;

import javafx.scene.layout.VBox;

import javafx.stage.Stage;

public class Ch2_13 extends Application {

/*

Before running this application, make sure to do these two steps:

1) Download JavaFX SDK for your OS from https://gluonhq.com/products/javafx/

and unzip it in any directory.

2) Assuming you have unzipped JavaFX SDK into the folder /path/JavaFX/,

add the following VM options to the Java command that launches this class:

--module-path /path/JavaFX/lib

--add-modules=javafx.controls,javafx.fxml

If you run it from IDE, add these VM options to Run Configuration.

Use JRE 9.* to execute this example since JRE 1.8 does not have these options.

*/

public static void main(String... args) {

launch(args);

}

@Override

public void start(Stage stage) {

ToggleButton toggleButton = new ToggleButton("TOGGLE ME");

Label label = new Label();

Observable<Boolean> selectedStates =

valuesOf(toggleButton.selectedProperty());

selectedStates.map(selected -> selected ? "DOWN" : "UP")

.subscribe(label::setText);

VBox vBox = new VBox(toggleButton, label);

stage.setScene(new Scene(vBox));

stage.show();

}

private static <T> Observable<T> valuesOf(final

ObservableValue<T> fxObservable) {

return Observable.create(observableEmitter -> {

//emit initial state

observableEmitter.onNext(fxObservable.getValue());

//emit value changes uses a listener

final ChangeListener<T> listener = (observableValue, prev,

current) -> observableEmitter.onNext(current);

fxObservable.addListener(listener);

});

}

}