import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.layout.VBox;
import javafx.stage.Modality;
import javafx.stage.Stage;

public class MsgBox {
    public static void show(String title, String msg) {
        Stage stage = new Stage();
        stage.initModality(Modality.APPLICATION_MODAL);
        stage.setTitle(title);

        Label label = new Label(msg);
        Button button = new Button("Bezár");
        button.setOnAction(e -> stage.close());
        VBox vbox = new VBox();
        vbox.getChildren().addAll(label, button);
        vbox.setAlignment(Pos.CENTER);

        Scene scene = new Scene(vbox, 300, 250);
        stage.setScene(scene);
        stage.show();
    }
}