iOS – 从NSUserDefaults获取NSDictionary：尝试取消引用无效的ObjC对象或向其发送无法识别的选择器

我尝试从已保存的NSUserDefaults中检索NSMutableArray.

我存储NSMutableArray：

NSUserDefaults * defaults = [NSUserDefaults standardUserDefaults];
NSMutableArray* mySavedTremps = [[defaults objectForKey:UD_MY_TREMPS] mutableCopy];

if (!mySavedTremps)
        mySavedTremps =[[NSMutableArray alloc] init];

NSMutableDictionary* trempDict = NSMutableDictionary* trempDict = [NSMutableDictionary DictionaryWithObjectsAndKeys:@"please",@"Help",@"me" @"!",nil]
[trempDict SETVALue:trempId forKey:@"trempId"];
[mySavedTremps insertObject:trempDict aTindex:0];
[defaults setObject:mySavedTremps forKey:UD_MY_TREMPS];

[defaults synchronize];

并尝试检索NSMutableArray：

NSMutableArray* myTrempsArray = [NSMutableArray arrayWithArray:[defaults objectForKey:UD_MY_TREMPS]];

for (TremP* tremp in myTrempsArray) {        
        if([tremp.trempId isEqualToString:@"1234"]) {
            [myTrempsArray removeObject:tremp];
            break;
        }
    }

但是,当我访问tremp(for循环中的param)时：

tremp.trempId

我收到此错误：

error: Execution was interrupted,reason: Attempted to dereference an invalid ObjC Object or send it an unrecognized SELEctor.

该过程已返回到表达式评估之前的状态.

for (NSDictionary *trempDict in myTrempsArray) {
    Tremp *tremp = ... // add code here to create a Tremp from the Dictionary
    if([tremp.trempId isEqualToString:@"1234"]) {
        [myTrempsArray removeObject:tremp];
        break;
    }
}