Android 4.4+ : check if path is on secondary storage

Question

My app has to check if a certain folder is on the secondary storage when the Android version is 4.4+.

I am using this:

private boolean isPathOnSecondaryStorage(String path) {
    boolean res=false;
    String secondaryStorage=System.getenv("SECONDARY_STORAGE");
    String[] secondaryPaths=secondaryStorage.split(":");
    for (int i=0;i<secondaryPaths.length;i++) {
        String secondaryPath=secondaryPaths[i].trim();
        if (path.contains(secondaryPath)) {
            res=true;
        }
    }
    return res;
}

Note that:

• path is chosen by the user by means of a file chooser activity, starting from /mnt

• the app wants to check what is mounted as usual, like when an external SD-card is inserted in its slot

So I ask whether the above mentioned code will be always able to detect when the path is on a secondary storage, or instead on some devices it could find strange mounting points different from /mnt (Android 4.4+).

Answer 1

Here is my current solution. Not ideal, but it should work.

/**
 * Uses the Environmental variable "SECONDARY_STORAGE" to locate a removable micro sdcard
 * 
 * @return  the primary secondary storage directory or
 *          {@code null} if there is no removable storage
 */
public static File getRemovableStorage() {
    final String value = System.getenv("SECONDARY_STORAGE");
    if (!TextUtils.isEmpty(value)) {
        final String[] paths = value.split(":");
        for (String path : paths) {
            File file = new File(path);
            if (file.isDirectory()) {
                return file;
            }
        }
    }
    return null;
}

/**
 * Checks if a file is on the removable SD card.
 * 
 * @see {@link Environment#isExternalStorageRemovable()}
 * @param file a {@link File}
 * @return {@code true} if file is on a removable micro SD card, {@code false} otherwise
 */
public static boolean isFileOnRemovableStorage(File file) {
    final File microSD = getRemovableStorage();
    if (microSD != null) {
        String canonicalPath;
        try {
            canonicalPath = file.getCanonicalPath();
            if (canonicalPath.startsWith(microSD.getAbsolutePath())) {
                return true;
            }
        } catch (IOException e) {
        }
    }
    return false;
}