iOS Facebook SDK startWithGraphPath:parameters post to just SOME friends programmatically - ios

Question

In Facebook, you can post something and share it with just some friends.
How can this be done programmatically on iOS using Facebook SDK?
My App has an "Emergency Button" that sends: a) User Location on a Map (picture); b) An emergency text (message); and c) The post is only shared with the friends the user has chosen in the config. section (privacy).
- (void)sendMessage {
//Just an Example: Send an Emergency Post with: message, picture, just to SOME friends.
//This action may not need the User to actually press a button.
//Privacy parameter obtained from:
//https://developers.facebook.com/docs/graph-api/reference/v2.0/post/
NSMutableDictionary *privacy = [[NSMutableDictionary alloc]initWithObjectsAndKeys:
#"100000278095294,100000278095528", #"allow", //Friends Id separeted with commas.
#"", #"deny",
#"CUSTOM", #"value", //Privacy Custom Value
nil];
NSMutableDictionary* params = [[NSMutableDictionary alloc] init];
[params setObject:self.emergencyText forKey:#"message"];
[params setObject:self.locationMap forKey:#"picture"];
[params setObject:privacy forKey:#"privacy"];
[FBRequestConnection startWithGraphPath:#"me/feed"
parameters:params
HTTPMethod:#"POST"
completionHandler:^(FBRequestConnection *connection,
id result,
NSError *error) {
if (error) {
NSLog(#"Error");
NSLog(#"Error descriptcion %#",error.description);
}else{
NSLog(#"Success");
}
}];
}
This code in not running. I get an error from Facebook.
If I comment this line:
// [params setObject:privacy forKey:#"privacy"];
Then it runs fine and I see the post in FB, but it is a public post.
I need to post: message, picture, just to some friends.
Any solution using startWithGraphPath or using any other command is welcome!

Answer 1

You must format the privacy as a JSON string and then assign that json string to the params NSMutableDictionary.
For Example:
NSMutableDictionary *privacy = [[NSMutableDictionary alloc]initWithObjectsAndKeys:
#"100000278095294,100000278095528", #"allow", //Friends Id separeted with commas.
#"", #"deny",
#"CUSTOM", #"value", //Privacy Custom Value
nil];
NSData *jsonData = [NSJSONSerialization dataWithJSONObject:privacy
options:NSJSONWritingPrettyPrinted
error:&error];
NSString *jsonString;
if (! jsonData) {
NSLog(#"Got an error: %#", error2);
} else {
jsonString = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
}
NSMutableDictionary* params = [[NSMutableDictionary alloc] init];
[params setObject:#"to my friend" forKey:#"message"];
[params setObject:self.locationMap forKey:#"picture"];
[params setObject:jsonString forKey:#"privacy"];