css - JavaFx 以编程方式设置外部背景图像

Question

我在动态设置锚定 Pane 的背景图像时遇到问题。出于开发目的，我将外部资源放在元素的 dist 文件夹中，因此文件可用。

AnchorPane 的代码:

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");

我想不通的是如何设置背景图片的路径。通读 CSS 和 JavaFX 引用，应该给出相对于 css 文件的路径。我还尝试创建 URL 和 URI 以及绝对路径。

// 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"

所有这些都不起作用:

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;");

(在旁注中文件存在，我检查了文件夹和文件的名称大小写，这也是正确的)

用于测试目的:

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文件:

.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 );
}

如果我将 css 和图像包含到 jar 文件中，一切都很好，但我想使用外部文件。像所有引用文献所说的那样设置相对于 css 文件的路径似乎不起作用，那么正确的路径是什么？

Answer 1

如果我用它把它放在 URL 中，这现在似乎可以工作了。

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

结果字符串与我的情况 7 相同，但我不知道为什么它以前不起作用，现在却起作用了。

我第一次在 SceneController 的构造函数中设置背景，现在我将它设置在一个额外的方法中，该方法在场景添加到舞台后被调用，也许这有什么作用，但我想不通真正的错误所在。

至于任何有类似问题的人的答案，最好使用 HostServices 来解析路径，如上例所示。