How can I get the external SD card path for Android 4.0+?

Question

Samsung Galaxy S3 has an external SD card slot, which is mounted to /mnt/extSdCard.

How can I get this path by something like Environment.getExternalStorageDirectory()?

This will return mnt/sdcard, and I can't find the API for the external SD card. (Or removable USB storage on some tablets.)

Answer 1

I have a variation on a solution I found here

public static HashSet<String> getExternalMounts() {
    final HashSet<String> out = new HashSet<String>();
    String reg = "(?i).*vold.*(vfat|ntfs|exfat|fat32|ext3|ext4).*rw.*";
    String s = "";
    try {
        final Process process = new ProcessBuilder().command("mount")
                .redirectErrorStream(true).start();
        process.waitFor();
        final InputStream is = process.getInputStream();
        final byte[] buffer = new byte[1024];
        while (is.read(buffer) != -1) {
            s = s + new String(buffer);
        }
        is.close();
    } catch (final Exception e) {
        e.printStackTrace();
    }

    // parse output
    final String[] lines = s.split("\n");
    for (String line : lines) {
        if (!line.toLowerCase(Locale.US).contains("asec")) {
            if (line.matches(reg)) {
                String[] parts = line.split(" ");
                for (String part : parts) {
                    if (part.startsWith("/"))
                        if (!part.toLowerCase(Locale.US).contains("vold"))
                            out.add(part);
                }
            }
        }
    }
    return out;
}

The original method was tested and worked with

• Huawei X3 (stock)
• Galaxy S2 (stock)
• Galaxy S3 (stock)

I'm not certain which android version these were on when they were tested.

I've tested my modified version with

• Moto Xoom 4.1.2 (stock)
• Galaxy Nexus (cyanogenmod 10) using an otg cable
• HTC Incredible (cyanogenmod 7.2) this returned both the internal and external. This device is kinda an oddball in that its internal largely goes unused as getExternalStorage() returns a path to the sdcard instead.

and some single storage devices that use an sdcard as their main storage

• HTC G1 (cyanogenmod 6.1)
• HTC G1 (stock)
• HTC Vision/G2 (stock)

Excepting the Incredible all these devices only returned their removable storage. There are probably some extra checks I should be doing, but this is at least a bit better than any solution I've found thus far.