Encryption / Decryption simple class on Android platform

I've been searching for a solution about encrypt/decryt string texts like it would be for example, the password. I had no idea how to do that buy after two days, I wrote my own encryption class, ready to use:
I use AES Algorithm, and unique key value for encryption for all uses.

public class Encriptacion 
{
 private static final String ALGORITMO = "AES";
        private static final byte[] valor_clave = "0000000000000000".getBytes(); 
 // key 16 bytes lenght (what you want and of course, valid characters)

 public static String encriptar (String texto_a_encriptar) throws Exception 
 {
  
  Key key = new SecretKeySpec(valor_clave, "AES");
  
  Cipher cipher = Cipher.getInstance("AES"); 
     cipher.init(Cipher.ENCRYPT_MODE, key );
     
  byte[] encrypted = cipher.doFinal(texto_a_encriptar.getBytes("UTF-8"));
  String texto_encriptado = Base64.encodeToString(encrypted, Base64.DEFAULT);//new String(encrypted, "UTF-8");

  return texto_encriptado;
  

 }
 
 public static String desencriptar(String texto_encriptado) throws Exception
 {
  
  Key key = new SecretKeySpec(valor_clave, ALGORITMO);
  
  Cipher cipher = Cipher.getInstance("AES");
        cipher.init(Cipher.DECRYPT_MODE, key);
        
        byte[] decodificar_texto = Base64.decode(texto_encriptado.getBytes("UTF-8"), Base64.DEFAULT);
        byte[] desencriptado = cipher.doFinal(decodificar_texto);
  
  return new String(desencriptado, "UTF-8");
 }
}

I've been doing a test and it works fine. If anyone reads it and if you want to leave a suggestion or improve, feel free to leave a message.