To change the privacy setting of a feed, you can add additional parameter- privacy
with your /me/feed
call.
JSONObject privacy = new JSONObject();
privacy.put("value", "EVERYONE");
params.putString("privacy", privacy.toString());
..... //other params
..... // make the call `/me/feed`
Please Note
A user can also manually sets the privacy of an application. To check this: go to your Facebook Settings, see what you've set your application to.The actual privacy applied will be the more restrictive privacy setting between the two.
eg.
If the user has set "Only Me" in the facebook settings, but in app you applied "Public", then the user's preference, i.e. Only Me will be used.
But if the user has set "Public" in the app settings, but in the app you applied "Friends", then the app's setting i.e. "Friends" is used, as it's more restrictive than the User's settings.
Hope that helps.