import javafx.application.Application;
import javafx.stage.Stage;
import javafx.scene.Scene;
import javafx.scene.layout.VBox;
import javafx.scene.control.Button;
import javafx.scene.control.TextField;
import javafx.event.EventHandler;
import javafx.event.ActionEvent;


public class HeiVerden extends Application{

  Button knapp = null;
  public TextField tekstfelt = null;

  @Override
  public void start(Stage stage){
    knapp = new Button("Si hei");
    KnappeBehandler behandler = new KnappeBehandler();
    knapp.setOnAction(behandler);
    tekstfelt = new TextField("Hilsen");

    VBox pane = new VBox(knapp);
    pane.getChildren().add(tekstfelt);

    stage.setScene(new Scene(pane));
    stage.show();
  }

  class KnappeBehandler implements EventHandler<ActionEvent>{
    @Override
    public void handle(ActionEvent e){
      String hilsen = tekstfelt.getText();
      knapp.setText(hilsen);
    }
  }

}