无法从 .plist 加载我的模型 (NSObject) 的所有对象

Question

你好

我已经在我的应用程序中创建了一个模型，其中我有ShoppingList和Items类(NSObject(。每个商品只有一个ShoppingList，ShoppingList有更多商品

(购物清单<-->>商品(

我已经将所有要plist的数据保存为NSArray和NSDictionary，但现在我在加载回我的项目时遇到了问题。

我的plist:

Root (NSArray)->>
___________Item 0(Dictionary)->>
________________________date(Date),name(String),items(Array)->> ____________________________________________________Item 0(Dictionary)->>
________________________________________________________________date(Date),name(String)

这是我写和读这个plist的代码：

- (NSDictionary *)propertyListRepresentation {
NSMutableArray *itemsAsPropertyLists = [NSMutableArray new];
for (Item *item in self.items) {
    NSDictionary *itemPropertyList = [item propertyListRepresentation];
    [itemsAsPropertyLists addObject:itemPropertyList];
}
return @{
         @"name": self.nameOfList ?: @"",
         @"date": self.date ?: [NSDate distantPast],
         @"items": itemsAsPropertyLists,
         };
}
+ (ShoppingList *)createFromPropertyListRepresentation:(NSDictionary *)plist {
ShoppingList *newList = [ShoppingList new];
newList.nameOfList = [plist objectForKey:@"name"];
newList.date = [plist objectForKey:@"date"];
return newList;
}
+ (NSArray *)loadPropertyList{
NSArray*loadData = [NSArray arrayWithContentsOfFile:@"/Users/Me/Desktop/saved.plist"];
NSMutableArray *shoppingLists = [NSMutableArray new];
for (NSDictionary *loadDictionary in loadData) {
     ShoppingList *shoppingList = [ShoppingList createFromPropertyListRepresentation:loadDictionary];
    [shoppingLists addObject:shoppingList];
     for (NSArray *array in loadDictionary) {
          NSArray *itemsArray = [NSArray new];
       itemsArray = [Item loadPropertyList:array];
       [shoppingLists addObject:itemsArray];
     }
}
return shoppingLists;

}

对于项目：

- (NSDictionary *)propertyListRepresentation {
return @{
         @"name": self.name ?: @" ",
        @"date" : self.date ?:[NSDate date],
         };
}
 +(Item*)createFromPropertyListRepresentation:(NSDictionary*)dict {
Item *newItems = [Item new];
newItems.name = [dict objectForKey:@"name"];
newItems.date = [dict objectForKey:@"date"];
return newItems;
}
+(NSArray*)loadPropertyList:(NSArray*)array {
NSMutableArray *listOfItems = [NSMutableArray new];
for (NSDictionary*dict in array) {
    Item *item = [Item createFromPropertyListRepresentation:dict];
    [listOfItems addObject:item];
    }
return listOfItems;
}

所以这个代码工作停止在线上工作

Item *item = [Item createFromPropertyListRepresentation:dict];

错误：

-[__NSCFString countByEnumeratingWithState:objects:count:]: unrecognized selector sent to instance
Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFString countByEnumeratingWithState:objects:count:]: unrecognized selector sent to instance

谢谢你的帮助。

Answer 1

NSDictionary对NSFastEnumeration的实现返回键，而不是对象。代替for (NSArray *array in loadDictionary)，您应该按照以下方式进行操作：

NSArray *itemPlist = [loadDictionary objectForKey: @"items"];
NSArray *items = [Item loadPropertyList: itemPlist];
[shoppingLists addObject: items];

但你可能也想对名字和日期做点什么。