Get a List of Files from a Classpath Resource Folder?-CodePudding

I'm trying to set an JFX ImageView image from a resource folder, but can't seem to get an appropriate URL/String filepath that won't throw an exception.

var x = getRandomImageFromPackage("pictures").toString();
var y = getClass().getClassLoader().getResource("pictures/mindwave/active/Super Saiyan.gif").toString();
this.iconImageView.setImage(new Image(x));

x returns

/home/sarah/Desktop/Dropbox/School/Current/MAX MSP Utilities/MindWaveMobileDataServer/target/classes/pictures/0515e3b7cb30ac92ebfe729440870a5c.jpg

whereas y returns something that looks like:

file:/home/sarah/Desktop/Dropbox/School/Current/MAX MSP Utilities/MindWaveMobileDataServer/target/classes/pictures/mindwave/active/Super Saiyan.gif

In theory either of these would be acceptable, however, only x will throw an exception if it is placed in the below setImage(String) line.

Is there any way to get a list of images in the package so that I can select a random one and set the ImageView?

I know that there was a custom scanner option, but it appears rather dated (being over 11 years old and wasn't really supported at the time):

CodePudding user response：

There is no easy and reliable way to do that. Therefore I create and put an inventory file into my resources folder. So at runtime I can read that in and then have all the file names awailable that I need.

Here is a little test that shows how I create that file:

public class ListAppDefaultsInventory {

    @Test
    public void test() throws IOException {
        List<String> inventory = listFilteredFiles("src/main/resources/app-defaults", Integer.MAX_VALUE);
        assertFalse("Directory 'app-defaults' is empty.", inventory.isEmpty());
        System.out.println("# src/main/resources/app-defaults-inventory.txt");
        inventory.forEach(s -> System.out.println(s));
    }
    
    public List<String> listFilteredFiles(String dir, int depth) throws IOException {
        try (Stream<Path> stream = Files.walk(Paths.get(dir), depth)) {
            return stream
                .filter(file -> !Files.isDirectory(file))
                .filter(file -> !file.getFileName().toString().startsWith("."))
                .map(Path::toString)
                .map(s -> s.replaceFirst("src/main/resources/app-defaults/", ""))
                .collect(Collectors.toList());
        }
    }
    
}

CodePudding user response：

Issues with your approach

You don't have a well-formed url

execution command

Set the VM arguments for your JavaFX SDK installation:

-p C:\dev\javafx-sdk-17.0.2\lib --add-modules javafx.controls