Returns a set of paths (as Strings) to the volumes mounted in an android device as external storage (such as SD cards and pendrives)

androidExternalStorage.java

private TreeSet<String> getMountedSdCards() {
  	String externalMain = Environment.getExternalStorageDirectory().getAbsolutePath();
		TreeSet<String> mountPaths = new TreeSet<String>();

		try {
			Scanner scanner = new Scanner(new File("/proc/mounts"));
			while (scanner.hasNext()) {
				String line = scanner.nextLine();
				if (line.startsWith("/dev/block/vold/")) {
					String[] lineElements = line.split(" ");
					String element = lineElements[1];

					if (!element.equals(externalMain)) {
						mountPaths.add(element);
					}
				}
			}
		} catch (Exception e) {
			// TODO Error
		}

		TreeSet<String> voldPaths = new TreeSet<String>();

		try {
			Scanner scanner = new Scanner(new File("/system/etc/vold.fstab"));
			while (scanner.hasNext()) {
				String line = scanner.nextLine();
				if (line.startsWith("dev_mount")) {
					String[] lineElements = line.split(" ");
					String element = lineElements[2];

					if (element.contains(":")) {
						element = element.substring(0, element.indexOf(":"));
					}

					if (!element.equals(externalMain)) {
						voldPaths.add(element);
					}
				}
			}
		} catch (Exception e) {
			// TODO Error
		}

		TreeSet<String> intersection = new TreeSet<String>(mountPaths);
		intersection.retainAll(voldPaths);

		Iterator<String> iterator = intersection.iterator();

		while (iterator.hasNext()) {
			String path = iterator.next();
			File pathFile = new File(path);
			if (!pathFile.exists() || !pathFile.isDirectory() /* || !pathFile.canWrite() */) {
				iterator.remove();
			}
		}

		return intersection;
	}