NSUserDefaults 存储可变数组问题

废话不多说上代码,项目中遇到的问题是:

NSMutableArray*arrayLoginNames=[NSMutableArrayarray];

arrayLoginNames=[[NSUserDefaultsstandardUserDefaults]mutableArrayValueForKey:KLastLoginNameForAutoSendMsgToKeFu];

这句话取出了数组,可是当对数组添加元素后,进行存储时卡在了下面这句话:

[[NSUserDefaultsstandardUserDefaults]setObject:arrayLoginNamesforKey:KLastLoginNameForAutoSendMsgToKeFu];

把主线程卡主,但是不崩溃,不知道为何,就Google了,stackoverflow给了解答办法,

WhenyoustoremutableobjectstoNSUserDefaults,itstoresanimmutablecopyofitsoyoucan'tchangeitdirectlylikethat.Youhavetogetthemutablecopyoutofdefaults,changeit,andthensetitback,replacingoldobjectindefaults.

NSUserDefaults*prefs=[NSUserDefaultsstandardUserDefaults];
NSMutableArray*mutableArrayCopy=[[prefsobjectForKey:@"theArray"]mutableCopy];
[mutableArrayCopyaddObject:@"somenewvalue"];
[prefssetObject:mutableArrayCopyforKey:@"theArray"];

[[NSUserDefaultsstandardUserDefaults]synchronize];