How to save and fetch in xmppGroupCoreDataStorageObject?

Question

Using xmpp-messenger-ios, I have created the group and set its configuration and adds the users into it, then I wants to add the group into the xmppGroupCoreD

Answer 1

Well, you are trying to send the message to an object that cannot respond to it.
Look at your exception log:

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFString managedObjectContext]: unrecognized selector sent to instance 0x7fdf8c545e50'***  

managedObjectContext message has been sent to an instance of NSString class.
Of course, it cannot respond to it and you are getting the crash.