JavaFX how to keep a certain aspect ratio

Question

Today I started learning JavaFx but I've run into a problem. For some reason when I use a GridPane to put a button and label on the screen, if I resize the window the button moves on the screen. The button and the label is staying in one place, and not moving alongside the window. How do I make it so that the button and label stay in their spot when resizing the window? I've read multiple pages but still can't find anything. Heres my code so far:

package application.alertboxes;

import javafx.geometry.Insets;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.layout.*;
import javafx.stage.Modality;
import javafx.stage.Stage;

public class infoBox {

    public static void display() {
        Stage window = new Stage();

        window.initModality(Modality.APPLICATION_MODAL);
        window.setTitle("Information");

        Label label = new Label("Test");

        Button closeButton = new Button("Close");
        closeButton.setOnAction(e -> window.close());

        GridPane layout = new GridPane();
        layout.setPadding(new Insets(10,10,10,10));
        layout.setVgap(8);
        layout.setHgap(10);

        GridPane.setConstraints(closeButton, 105, 80);
        GridPane.setConstraints(label, 75, 50);

        layout.getChildren().addAll(closeButton, label);

        Scene scene = new Scene(layout, 1200, 720);
        window.setScene(scene);
        window.showAndWait();

    }

}

Answer 1

Add the appropriate constrains to all GripPane cells:

import javafx.application.Application;
import javafx.geometry.*;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.layout.*;
import javafx.stage.Stage;

public class FxMain extends Application{

    private static final int ROWS = 10, COLS = 10;
    @Override
    public void start(Stage window)   {

         Label label = new Label("Test");

         Button closeButton = new Button("Close");
         closeButton.setOnAction(e -> window.close());

         GridPane layout = new GridPane();
         layout.setPadding(new Insets(10,10,10,10));
         layout.setVgap(8);
         layout.setHgap(10);

         GridPane.setConstraints(closeButton, 8, 8);
         GridPane.setConstraints(label, 4, 4);
         //set vgrow to all rows to always 
         for (int row = 0; row < ROWS; row++) {
               layout.getRowConstraints()
                   .add(new RowConstraints(-1, -1, -1, Priority.ALWAYS, VPos.CENTER, false));
         }

         //set hgrow to all columns to always 
         for (int col = 0; col <COLS; col++) {
             layout.getColumnConstraints()
                 .add(new ColumnConstraints(-1, -1, -1, Priority.ALWAYS, HPos.CENTER, false));
         }

         layout.getChildren().addAll(closeButton, label);

         Scene scene = new Scene(layout, 320, 200);
         window.setScene(scene);
         window.show();
    }

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