在没有LoginButton的情况下询问Facebook权限

Question

如何使用此基本代码获得Facebook权限：

Session.openActiveSession(this, true, new Session.StatusCallback() {

    // callback when session changes state
    @Override
    public void call(Session session, SessionState state, Exception exception) {
        Log.d("call", "Called : " + state.toString());
        if (session.isOpened()) {
            Log.d("session.isOpened()", "Called");
            // make request to the /me API

            Request.executeMeRequestAsync(session, new Request.GraphUserCallback() {
                // callback after Graph API response with user object
                @Override
                public void onCompleted(GraphUser user, Response response) {
                    Log.d("onCompleted", "Called");
                    if (user != null) {
                    } catch (JSONException e) {
                        e.printStackTrace();
                    }
                }
            });
        }
    }
}

请使用此代码告诉我如何添加权限。

我看到了这段代码：

private static Session
openActiveSession(Activity activity, boolean allowLoginUI, StatusCallback callback, List<String> permissions)
{
    Log.d("openActiveSession","called");
    OpenRequest openRequest = new OpenRequest(activity).setPermissions(permissions).setCallback(callback);
    Session session = new Builder(activity).build();
    if (SessionState.CREATED_TOKEN_LOADED.equals(session.getState()) || allowLoginUI) {
        Session.setActiveSession(session);
        session.openForRead(openRequest);
        return session;
    }
    return null;
}

但我不知道这是否是最简单的方法，或者如何以及何时实施它。