JavaFX VBox and HBox layouts

问题

I'm working on a JavaFX application which has a layout generated from an external data structure, composed of

displaying components that know their own aspect ratios (height as a dependent of width)
2 types of structural components that
- display all children with an equal width across their page, each child up as much vertical space as needed
- display all children down the page using the full width and taking as much vertical space as needed

But I'm finding things aren't displaying as I expect. I've made a simplified case that demonstrates the problem.

The code is below, and the problem is that v3 doesn't get displayed, and I can't for the life of me work out why. I guess there's some facet of VBoxes and HBoxes that I haven't understood.

I'd really appreciate any help or ideas. Thanks in advance!

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.layout.HBox;
import javafx.scene.layout.Priority;
import javafx.scene.layout.Region;
import javafx.scene.layout.VBox;
import javafx.scene.paint.Color;
import javafx.scene.shape.Rectangle;
import javafx.stage.Stage;

import java.util.Random;

public class Test extends Application {

    static Random rand = new Random();

    public static void main(String args[]) {
        Application.launch("something");
    }

    @Override
    public void start(Stage mainStage) throws Exception {
        testVBoxes(mainStage);
    }

    private void testVBoxes(Stage mainStage) {
        VBox root = new VBox();
        Scene one = new Scene(root, 800, 600, Color.WHITE);

        FixedAspectRatioH h1 = new FixedAspectRatioH();
        FixedAspectRatioH h2 = new FixedAspectRatioH();
        FixedAspectRatioH h3 = new FixedAspectRatioH();
        FixedAspectRatioV v1 = new FixedAspectRatioV();
        FixedAspectRatioV v2 = new FixedAspectRatioV();
        FixedAspectRatioV v3 = new FixedAspectRatioV();

        h1.prefWidthProperty().bind(root.widthProperty());

        h2.add(v2);

        v1.add(h3);
        v1.add(h2);

        h1.add(v1);
        h1.add(v3);

        root.getChildren().add(h1);

        mainStage.setScene(one);
        mainStage.show();
    }

    private class FixedAspectRatioV extends VBox {
        public FixedAspectRatioV() {
            Rectangle r = new Rectangle();
            r.setFill(Color.rgb(rand.nextInt(256), rand.nextInt(256),     rand.nextInt(256)));
            r.widthProperty().bind(widthProperty());
            r.heightProperty().bind(r.widthProperty().divide(3));
            getChildren().add(r);
        }

        public void add(Region n) {
            n.prefWidthProperty().bind(widthProperty());
            getChildren().add(n);
        }
    }

    private class FixedAspectRatioH extends HBox {
        public FixedAspectRatioH() {
            Rectangle r = new Rectangle();
            r.setFill(Color.rgb(rand.nextInt(256), rand.nextInt(256),     rand.nextInt(256)));
            r.widthProperty().bind(widthProperty().divide(4));
            r.heightProperty().bind(r.widthProperty());
            getChildren().add(r);
        }

        public void add(Region n) {
            HBox.setHgrow(n, Priority.ALWAYS);
            getChildren().add(n);
        }
    }
}

回答1:

its 2 years but the solution is you forgot

Node.setPrefSize(width,height);

and also add this to your constructor Hbox.setFillHeight(true);

来源：https://stackoverflow.com/questions/15302961/javafx-vbox-and-hbox-layouts

标签

layout

javafx-2