android-async-http的使用

public String getXmlFromServer(final Context usingcontext,
 String method, String sentence) {
    String path = usingcontext.getString(R.string.server_path) + method;
    Log.e("111", path);
    RequestParams params = new RequestParams();
    params.put("sentence", sentence);

    AsyncHttpClient client = new AsyncHttpClient();
    client.post(path, params, new TextHttpResponseHandler() {
        @SuppressWarnings("deprecation")
        @Override
        // 请求成功
        public void onSuccess(int statusCode, Header[] headers,
                String response) {

                super.onSuccess(statusCode, headers, response);
                SystemClock.sleep(1000);
                 stringResult = response.toString();
                for (int i = 0; i < stringResult.length(); i++) {
                    if (stringResult.charAt(i) != ' ') {

                        stringResult = stringResult.substring(i, stringResult.length());

                        break;

                    }
                }
                stringResult = stringResult.trim();
                Toast.makeText(usingcontext, stringResult, Toast.LENGTH_LONG)
                .show();


        }

        @Override
        @Deprecated
        public void onFailure(int context, Header[] headers,
                Throwable error, String content) {
            Toast.makeText(usingcontext, "服务器忙请稍后重试", Toast.LENGTH_LONG)
                    .show();

        }
    });

    return stringResult;
}

求解