I solve that problem. It needs to add provider by a new way. Like this.
static {Security.insertProviderAt(new org.spongycastle.jce.provider.BouncyCastleProvider(), 1);}
and the code what to generate a key pair:
try {
ECGenParameterSpec ecParamSpec = new ECGenParameterSpec("secp224k1");
KeyPairGenerator kpg = KeyPairGenerator.getInstance("ECDH","SC");
kpg.initialize(ecParamSpec);
KeyPair kpair=kpg.generateKeyPair();
pkey=kpair.getPublic();
skey=kpair.getPrivate();
}catch(Exception e){e.printStackTrace();}
thanks