You are so close
You don't need the first forward slash and you were passing the resourceID instead of the actual App IP. So the updated code will look like this..
public static void getFriendsScores() {
Request postScoreRequest = new Request(Session.getActiveSession(),
getResources().getString(R.string.app_id) +"/scores", null, HttpMethod.GET,
new Request.Callback() {
@Override
public void onCompleted(Response response) {
FacebookRequestError error = response.getError();
if (error != null) {
Log.d("getting all scores",
"Getting Scores from Facebook failed: "
+ error.getErrorMessage());
Scores.isFriendsScoresLoaded = false;
} else {
Log.d("getting all scores",
"Got Scores successfully from Facebook");
Log.d("score object", response.getGraphObject()
.getInnerJSONObject().toString());
Scores.isFriendsScoresLoaded = true;
}
}
});
Request.executeBatchAsync(postScoreRequest);
}