在[EXC_BAD_ACCESS NSKeyedUnarchiver unarchiveObjectWithData:];

I found the answer after I set the bounty. If somebody has some useful comments on my approach (I don't know if it is the 'right' solution) he/she can have the bounty. If you're going to downvote my question, please leve a comment so I can improve future questions.I found the answer after I set the bounty. If s