O de Android é este aqui: https://github.com/gerencianet/gn-api-sdk-android
E lá tem este exemplo:
HashMap options = new HashMap();
options.put("account_id", "__ACCOUNT_ID__");
options.put("sandbox", true);
Map card = new HashMap<>();
card.put("brand", "mastercard");
card.put("number", "1111111111111111");
card.put("cvv", "123");
card.put("expiration_month", "12");
card.put("expiration_year", "1234");
try {
Gerencianet gn = new Gerencianet(options);
Map response = gn.call("paymentToken", new HashMap(), card);
System.out.println(response);
}catch (GerencianetException e){
System.out.println(e.getCode());
System.out.println(e.getError());
System.out.println(e.getErrorDescription());
}
catch (Exception e) {
e.printStackTrace();
System.out.println(e.getMessage());
}