JavaFx set external background image programmatica

Question

I have problems setting a background image of an anchor pane dynamically. For developing purpose i put the external resources in the dist folder of the project, so the files are availiable.

Code for the AnchorPane:

AnchorPane root = new AnchorPane();
// this works fine, styles inside the css are used in components on the root pane
root.getStylesheets().add("file:/D:/ProjectFolder/global.css");

What i can't figure out is how to set the path for a background image. Reading through the CSS and JavaFX references the path should be given relative to the css file. I also tried to creare URLs and URIs and absolute paths.

// path of compiled jar
"D:/ProjectFolder/project.jar"
// path of css file
"D:/ProjectFolder/global.css"
// path of background file
"D:/ProjectFolder/Resources/Wallpapers/worldmap.jpg"

All of these dont work:

root.setStyle("-fx-background-image: url('Resources/Wallpapers/worldmap.jpg'); -fx-background-repeat: stretch; -fx-background-size: stretch; -fx-background-position: center center;");
root.setStyle("-fx-background-image: url('/Resources/Wallpapers/worldmap.jpg'); -fx-background-repeat: stretch; -fx-background-size: stretch; -fx-background-position: center center;");
root.setStyle("-fx-background-image: url('./Resources/Wallpapers/worldmap.jpg'); -fx-background-repeat: stretch; -fx-background-size: stretch; -fx-background-position: center center;");
root.setStyle("-fx-background-image: url('@Resources/Wallpapers/worldmap.jpg'); -fx-background-repeat: stretch; -fx-background-size: stretch; -fx-background-position: center center;");
root.setStyle("-fx-background-image: url('@/Resources/Wallpapers/worldmap.jpg'); -fx-background-repeat: stretch; -fx-background-size: stretch; -fx-background-position: center center;");
root.setStyle("-fx-background-image: url('@./Resources/Wallpapers/worldmap.jpg'); -fx-background-repeat: stretch; -fx-background-size: stretch; -fx-background-position: center center;");
root.setStyle("-fx-background-image: url('D:/ProjectFolder/Resources/Wallpapers/worldmap.jpg'); -fx-background-repeat: stretch; -fx-background-size: stretch; -fx-background-position: center center;");
root.setStyle("-fx-background-image: url('file:/D:/ProjectFolder/Resources/Wallpapers/worldmap.jpg'); -fx-background-repeat: stretch; -fx-background-size: stretch; -fx-background-position: center center;");

(on a sidenote the files exist, i checked the names of folders and files for case, this is correct too)

For testing purpose:

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

public class BackGroundTest extends Application {

    private int backgroundtest = 0;
    private AnchorPane root;

    @Override
    public void start(Stage primaryStage) {
        Button btn = new Button();
        btn.setText("Test Background");
        btn.setOnAction(new EventHandler<ActionEvent>() {
            @Override
            public void handle(ActionEvent event) {
                switch (backgroundtest) {
                    case 0: {
                        root.setStyle("-fx-background-image: url('Resources/Wallpapers/worldmap.jpg'); -fx-background-repeat: stretch; -fx-background-size: stretch; -fx-background-position: center center;");
                        break;
                    }
                    case 1: {
                        root.setStyle("-fx-background-image: url('/Resources/Wallpapers/worldmap.jpg'); -fx-background-repeat: stretch; -fx-background-size: stretch; -fx-background-position: center center;");
                        break;
                    }
                    case 2: {
                        root.setStyle("-fx-background-image: url('./Resources/Wallpapers/worldmap.jpg'); -fx-background-repeat: stretch; -fx-background-size: stretch; -fx-background-position: center center;");
                        break;
                    }
                    case 3: {
                        root.setStyle("-fx-background-image: url('@Resources/Wallpapers/worldmap.jpg'); -fx-background-repeat: stretch; -fx-background-size: stretch; -fx-background-position: center center;");
                        break;
                    }
                    case 4: {
                        root.setStyle("-fx-background-image: url('@/Resources/Wallpapers/worldmap.jpg'); -fx-background-repeat: stretch; -fx-background-size: stretch; -fx-background-position: center center;");
                        break;
                    }
                    case 5: {
                        root.setStyle("-fx-background-image: url('@./Resources/Wallpapers/worldmap.jpg'); -fx-background-repeat: stretch; -fx-background-size: stretch; -fx-background-position: center center;");
                        break;
                    }
                    case 6: {
                        root.setStyle("-fx-background-image: url('D:/ProjectFolder/Resources/Wallpapers/worldmap.jpg'); -fx-background-repeat: stretch; -fx-background-size: stretch; -fx-background-position: center center;");
                        break;
                    }
                    case 7: {
                        root.setStyle("-fx-background-image: url('file:/D:/ProjectFolder/Resources/Wallpapers/worldmap.jpg'); -fx-background-repeat: stretch; -fx-background-size: stretch; -fx-background-position: center center;");
                        break;
                    }
                }
                backgroundtest++;
                if (backgroundtest == 8) {backgroundtest = 0;}
            }
        });
        root = new AnchorPane();
        root.getStylesheets().add("file:/D:/ProjectFolder/global.css");
        StackPane stack = new StackPane();
        root.getChildren().add(stack);
        AnchorPane.setBottomAnchor(stack, 0d);
        AnchorPane.setLeftAnchor(stack, 0d);
        AnchorPane.setRightAnchor(stack, 0d);
        AnchorPane.setTopAnchor(stack, 0d);
        stack.getChildren().add(btn);

        Scene scene = new Scene(root, 800, 600);

        primaryStage.setTitle("Test Background");
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    /**
     * The main() method is ignored in correctly deployed JavaFX application.
     * main() serves only as fallback in case the application can not be
     * launched through deployment artifacts, e.g., in IDEs with limited FX
     * support. NetBeans ignores main().
     *
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        launch(args);
    }
}

css file :

.button {
    -fx-background-color:
        rgb(0, 50, 0, 0.08),
        rgb(0, 0, 0, 0.8),
        #090a0c,
        linear-gradient(#4a5661 0%, #1f2429 20%, #1f242a 80%),
        linear-gradient(#242a2e, #23282e),
        radial-gradient(center 50% 0%, radius 100%, rgba(135,142,148,0.9), rgba(255,255,255,0));
    -fx-background-radius: 7, 6, 5, 4, 3, 5;
    -fx-background-insets: -3 -3 -4 -3, -3, 0, 1, 2, 0;
    -fx-font-family: "Arial";
    -fx-font-size: 14;
    -fx-text-fill: white;
    -fx-padding: 5 10 5 10;
    -fx-effect: dropshadow( one-pass-box , rgb(0, 255, 0, 0.6), 10, 0.5 , 0 , 1 );
}

It all works well if i include the css and the image into the jar file, but i want to use external files. Setting the path relative to the css file like all the references say does not seem to work, so what would be the correct path ?

Answer 1

This seems to work now if i use this to put it in the URL.

String filename = "worldmap.jpg"; 
HostServices services = this.getHostServices(); 
String url = services.resolveURI(services.getCodeBase(), "Resources/Wallpapers/" + filename);

The resulting string is the same as in my case 7 tho, i dont know why it did not work before and now does.

I set the background in the constructor of the SceneController the first time, now i set it in an extra method that gets called after the scene is added to the stage, maybe that has something to do it, but i cant figure out where the mistake realy lies.

As for an answer to anyone haveing similar problems, it is best to use the HostServices to resolve paths like in the example above.

Answer 2

Don't know if you got it working but here is the correct answer:

root.setStyle("-fx-background-image: url('file://D:/ProjectFolder/Resources/Wallpapers/worldmap.jpg');");

The file implementation should be 'file://PATH'