public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        String hash=getMD5Hash("1234");
        Toast.makeText(this, hash, Toast.LENGTH_SHORT).show();
    }
    
    public static String getMD5Hash(String s) {
        MessageDigest m = null;
        String hash = null;
    
        try {
         m = MessageDigest.getInstance("MD5");
         m.update(s.getBytes(),0,s.length());
         hash = new BigInteger(1, m.digest()).toString(16);
        } catch (NoSuchAlgorithmException e) {
         e.printStackTrace();
        }
    
        return hash;
   }