import java.util.Arrays;
import java.util.List;
import javafx.application.Application;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.geometry.Orientation;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.ComboBox;
import javafx.scene.layout.FlowPane;
import javafx.stage.Stage;

public class Main extends Application {

    ObservableList<String> theList = FXCollections.observableArrayList();

    @Override
    public void start(Stage primaryStage) throws Exception{
        primaryStage.setTitle("Sample");
        FlowPane root = new FlowPane(Orientation.VERTICAL);
        root.setVgap(20);

        List<String> initialColors = Arrays.asList("red", "green", "blue", "black");
        theList.addAll(initialColors);

        ComboBox<String> theComboBox = new ComboBox<>();
        theComboBox.setItems(theList);
// theComboBox.setOnAction( event -> {
// System.out.println(String.format("theComboBox action listener triggered, current value is %s", theComboBox.getValue()));
// });

        theComboBox.valueProperty().addListener((observable, oldValue, newValue)->{
            System.out.println(String.format("theComboBox action listener triggered, current value is %s", theComboBox.getValue()));
        });

        Button bttn1 = new Button("Press me");
        bttn1.setOnAction(event -> {
            List<String> someColors = Arrays.asList("red", "orange", "mauve", "pink", "blue", "salmon", "chiffon");
            System.out.println("About to issue setAll against observable list");
            theList.setAll(someColors);
        });

        root.getChildren().add(theComboBox);
        root.getChildren().add(bttn1);

        primaryStage.setScene(new Scene(root, 100, 150));
        primaryStage.show();

        System.out.println("Setting initial selection to \"blue\"");
        theComboBox.setValue("blue");
    }


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