I can not get the real way to a removable SD card. Is there any way to get?

Question

On some device, it returns the actual path to the removable SD card, but in some form it returns null.

Basically, I want to store the file in accordance with the user either on the internal memory of the device or on the external one (removable storage (micro SD-card)). I need to do this from jelly bean to 6.0

public static String getExternalStroagePath(Context context) {
  // storage types
    final String FLAG = "mnt";
    final String SECONDARY_STORAGE = System.getenv("SECONDARY_STORAGE");
    final String EXTERNAL_STORAGE_DOCOMO = System.getenv("EXTERNAL_STORAGE_DOCOMO");
    final String EXTERNAL_SDCARD_STORAGE = System.getenv("EXTERNAL_SDCARD_STORAGE");
    final String EXTERNAL_SD_STORAGE = System.getenv("EXTERNAL_SD_STORAGE");
    final String EXTERNAL_STORAGE = System.getenv("EXTERNAL_STORAGE");

    Map<Integer, String> listEnvironmentVariableStoreSDCardRootDirectory = new HashMap<Integer, String>();

// add all storage to map
    listEnvironmentVariableStoreSDCardRootDirectory.put(0,SECONDARY_STORAGE);
    listEnvironmentVariableStoreSDCardRootDirectory.put(1,EXTERNAL_STORAGE_DOCOMO);
    listEnvironmentVariableStoreSDCardRootDirectory.put(2,EXTERNAL_SDCARD_STORAGE);
    listEnvironmentVariableStoreSDCardRootDirectory.put(3,EXTERNAL_SD_STORAGE);
    listEnvironmentVariableStoreSDCardRootDirectory.put(4, XTERNAL_STORAGE);

    File externalStorageList[] = null;
    String directory = null;
 //check version 
    if (android.os.Build.VERSION.SDK_INT > android.os.Build.VERSION_CODES.KITKAT) {
        externalStorageList = context.getExternalFilesDirs(null);
    }
    int size = listEnvironmentVariableStoreSDCardRootDirectory.size();
    for (int i = 0; i < size; i++) {
        if (externalStorageList != null && externalStorageList.length > 1 && externalStorageList[1] != null)
            directory = externalStorageList[1].getAbsolutePath();
        else
            directory = listEnvironmentVariableStoreSDCardRootDirectory.get(i);
        directory = canCreateFile(directory);
        if (directory != null && directory.length() != 0) {
            if (i == size - 1) {

                if (directory.contains(FLAG)) {
                    return directory;
                } else {
                    return null;
                }
            }
            return directory;
        }
    }
    return null;
}