private static String bytesToHex(byte[] byteArray) {
    final StringBuilder sb = new StringBuilder();
    for (byte b : byteArray) {
      sb.append(String.format("%02X", b));
    }
    return sb.toString();
  }
Obtains the SHA-1 fingerprint of the certificate used to sign the app.

@param context a Context
@return the SHA-1 fingerprint if obtainable, otherwise, <code>null</code>
src/main/java/com/google/maps/android/CertificateHelper.java