Android:usar SSL/HTTPS para conectarse con PHP a la base de datos y usar POST/GET

Log.e("body", body);
            HttpClient httpclient = getNewHttpClient();

            HttpPost httppost = new HttpPost("https://www.demo.com/login.php");

             nameValuePairs = new ArrayList<NameValuePair>();
nameValuePairs.add(new BasicNameValuePair("username", username));
nameValuePairs.add(new BasicNameValuePair("password", password));
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));


            httppost.setEntity(entity);
            response = httpclient.execute(httppost);;


            Log.e("response", response.getStatusLine().toString());
            String aaa = response.getStatusLine().toString();
            Toast.makeText(getApplicationContext(), "Content :"+ aaa, Toast.LENGTH_LONG).show();
            HttpEntity entity1 = response.getEntity();
            is = entity1.getContent();

                //Toast.makeText(getApplicationContext(), "Content :"+ (CharSequence) is, Toast.LENGTH_LONG).show();

        }catch(Exception e){
            Log.e("log_tag", "Error in http connection "+e.toString());
        }


public HttpClient getNewHttpClient() {
        try {
            KeyStore trustStore = KeyStore.getInstance(KeyStore
                    .getDefaultType());
            trustStore.load(null, null);

            SSLSocketFactory sf = new MySSLSocketFactory(trustStore);
            sf.setHostnameVerifier(SSLSocketFactory.ALLOW_ALL_HOSTNAME_VERIFIER);

            HttpParams params = new BasicHttpParams();
            HttpProtocolParams.setVersion(params, HttpVersion.HTTP_1_1);
            HttpProtocolParams.setContentCharset(params, HTTP.UTF_8);

            SchemeRegistry registry = new SchemeRegistry();
            registry.register(new Scheme("http", PlainSocketFactory
                    .getSocketFactory(), 80));
            registry.register(new Scheme("https", sf, 443));

            ClientConnectionManager ccm = new ThreadSafeClientConnManager(
                    params, registry);

            return new DefaultHttpClient(ccm, params);
        } catch (Exception e) {
            return new DefaultHttpClient();
        }
    }

MySSLSocketFactory.java

public class MySSLSocketFactory extends SSLSocketFactory {
    SSLContext sslContext = SSLContext.getInstance("TLS");

    public MySSLSocketFactory(KeyStore truststore) throws NoSuchAlgorithmException, KeyManagementException, KeyStoreException, UnrecoverableKeyException {
        super(truststore);

        TrustManager tm = new X509TrustManager() {
            public void checkClientTrusted(X509Certificate[] chain, String authType) throws CertificateException {
            }

            public void checkServerTrusted(X509Certificate[] chain, String authType) throws CertificateException {
            }

            public X509Certificate[] getAcceptedIssuers() {
                return null;
            }
        };

        sslContext.init(null, new TrustManager[] { tm }, null);
    }

    @Override
    public Socket createSocket(Socket socket, String host, int port, boolean autoClose) throws IOException, UnknownHostException {
        return sslContext.getSocketFactory().createSocket(socket, host, port, autoClose);
    }

    @Override
    public Socket createSocket() throws IOException {
        return sslContext.getSocketFactory().createSocket();
    }
}

Agregue esto si trabaja por encima de 4.0, en su código

 StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
         StrictMode.setThreadPolicy(policy);