廢話不多說上程式碼,專案中遇到的問題是:

NSMutableArray * arrayLoginNames = [NSMutableArray array];

arrayLoginNames  = [[NSUserDefaults standardUserDefaults] mutableArrayValueForKey:KLastLoginNameForAutoSendMsgToKeFu];

這句話取出了陣列,可是當對陣列新增元素後,進行儲存時卡在了下面這句話:

[[NSUserDefaults standardUserDefaults] setObject:arrayLoginNames forKey:KLastLoginNameForAutoSendMsgToKeFu];

把主執行緒卡主,但是不崩潰,不知道為何,就Google了,stackoverflow給瞭解答辦法,

When you store mutable objects to NSUserDefaults, it stores an immutable copy of it so you can't change it directly like that. You have to get the mutable copy out of defaults, change it, and then set it back, replacing old object in defaults.

NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];
NSMutableArray *mutableArrayCopy = [[prefs objectForKey:@"theArray"] mutableCopy];
[mutableArrayCopy addObject:@"some new value"];
[prefs setObject:mutableArrayCopy forKey:@"theArray"];
 

[[NSUserDefaults standardUserDefaults] synchronize];