iOS native sharing UIActivity for Sincerely's Ship Framework
// intialize the activity
ActivityPostcard *postcardActivity = [[ActivityPostcard alloc] init];
// set the image
NSArray *activityItems = @[postcardImage];
// create the activty controller
UIActivityViewController* activityController = [[UIActivityViewController alloc] initWithActivityItems:activityItems applicationActivities:@[postcardActivity]];
// present the activty controller
[self presentViewController:activityController animated:YES completion:nil];
// handle outcome
[activityController setCompletionHandler:^(NSString *activityType, BOOL completed) {
}];