您好，我想使用NSUserDefaults保存和检索NSObject类，因为我写了下面的代码，但出现如下异常Terminatingappduetouncaughtexception'NSInvalidArgumentException',reason:'Attempttoinsertnon-propertylistobjectforkeyDATA'为了节省:-SavingBean*savingbean=[[SavingBeanalloc]init];[savingbeansavingData:userName.text:passWord.text];NSUserDefaults*def