将自定义的类的数据以数组的形式直接存储到NSUserDefaults中会报错，需要进行转换，且需要将该类实现NSCoding协议。
e.g.
存储过程
NSMutableArray *archiveArr = [NSMutableArray arrayWithCapacity:self.STNArrayList.count];
for (STNArrayList *singleList in self.STNArrayList) {NSData *listEncodedObject = [NSKeyedArchiver archivedDataWithRootObject:singleList];[archiveArr addObject:listEncodedObject];} //可以将archiveArr存入NSUserDefaults中了
读取过程
NSArray *localSavedArr = ;//从NSUserDefaults中读取本地存储的数据NSMutableArray *mutableArr = [NSMutableArray arrayWithCapacity:localSavedArr.count];for (NSData *data in localSavedArr) {STNArrayList *singleList = [NSKeyedUnarchiver unarchiveObjectWithData:data];[mutableArr addObject:singleList];}// 现在可以访问mutableArr来获得STNArrayList的值
在STNArrayList类中实现NSCoding协议
- (id)initWithCoder:(NSCoder *)aDecoder {if (self == [super init]) {_title = [aDecoder decodeObjectForKey:JSON_KEY];}return self; }- (void)encodeWithCoder:(NSCoder *)aCoder {[aCoder encodeObject:_title forKey:JSON_KEY]; }
)
