I implemented a function to open an AlertView when I receive a remote notification like this:
func application(application: UIApplication, didReceiveRemoteNo         
        
This is my version for objC
if (userInfo[@"aps"]){
    NSDictionary *aps = userInfo[@"aps"];
    if (aps[@"alert"]){
        NSObject *alert = aps[@"alert"];
        if ([alert isKindOfClass:[NSDictionary class]]){
            NSDictionary *alertDict = aps[@"alert"];
            if (alertDict[@"message"]){
                NSString *message = alertDict[@"message"];
            }
        }
        else if (aps[@"alert"]){
            NSString *alert = aps[@"alert"];
        }
    }
}