@Override
 public void onCreate(@Nullable Bundle savedInstanceState) {
   super.onCreate(savedInstanceState);
   mContext = getActivity();
   username = PreferenceUtil.getString(mContext, Const.USERNAME, null);
   mHandler = new Handler();
 }
  private ApiManager() {
    mContext = GithubApplication.getInstance();
    mAccessToken = PreferenceUtil.getString(mContext, Const.ACCESS_TOKEN_KEY, null);
    OkHttpClient okHttpClient = new OkHttpClient();
    okHttpClient.setReadTimeout(60, TimeUnit.SECONDS);
    okHttpClient.setConnectTimeout(60, TimeUnit.SECONDS);
    mRestAdapter =
        new RestAdapter.Builder()
            .setRequestInterceptor(mRequestInterceptor)
            .setEndpoint(API_URL)
            .setClient(new OkClient(okHttpClient))
            .build();

    mGithubApi = mRestAdapter.create(GithubApi.class);
  }