声明NSDictionary并在Swift中添加键值对？

Question

我一直在尝试使用类类型键声明一个NSDictionary,其值如下:

var catAndSubCatDict: NSDictionary<Category, Array<SubCategory>> = NSDictionary<Category, Array<SubCategory>>()

这里,"Category"和"SubCategory"是全局类.我知道我不能将类类型用于关键字段.但是,无论如何,我应该做到这一点.有没有办法做到这一点？如何声明专门的NSDictionary或类似的东西来做到这一点？

另外,我使用这样的字典:

for(var i=0; i<resultJson.count; i++)
{
   let subCategoryItemList = resultJson.objectAtIndex(i) as NSDictionary
   let categoryItem = subCategoryItemList.valueForKey(WSConstants.CATEGORY_OBJ) as NSDictionary

   var category: Category = Category()
   category.categoryId    = categoryItem.valueForKey(WSConstants.CATEGORY_ID) as Int
   category.categoryName  = categoryItem.valueForKey(WSConstants.NAME) as String

   var subCategoryList: Array<SubCategory> = []
   let jsonSubCategoryList = subCategoryItemList.allKeysForObject(WSConstants.SUBCATEGORY_LIST_OBJ) as NSArray

   for(var i=0; i<jsonSubCategoryList.count; i++)
   {
      let subCategoryObj = jsonSubCategoryList.objectAtIndex(i) as NSDictionary

      var subCategory: SubCategory = SubCategory()
      subCategory.subCategoryId    = subCategoryObj.valueForKey(WSConstants.SUBCATEGORY_ID) as Int
      subCategory.subCategoryName  = subCategoryObj.valueForKey(WSConstants.NAME) as String
      subCategory.subCategoryType  = subCategoryObj.valueForKey(WSConstants.SUBCATEGORY_TYPE) as Int

      subCategoryList.append(subCategory)
   }
   self.catAndSubCatDict.setValue(category, forkey: subCategoryList) // Also, I have to achieve this
}

谢谢您的回答,

最好的祝福

Answer 1

NSDictionary它不支持泛型,所以你不能声明的方式-如果你想使用它,如下实例吧:

var catAndSubCatDict: NSDictionary = NSDictionary()

雨燕提供了一个新的字典类型,它不支持泛型,并建立它,你只需要更换NSDictionary与Dictionary您的代码:

var catAndSubCatDict: Dictionary<Category, Array<SubCategory>> = Dictionary<Category, Array<SubCategory>>()

或使用以下紧凑形式之一:

var catAndSubCatDict: [Category : Array<SubCategory>] = [Category : Array<SubCategory>]()

var catAndSubCatDict: [Category : [SubCategory]] = [Category : [SubCategory]]()

请注意,在上面提到的所有情况下,您可以使用类型推断并通过删除变量类型来缩短代码:

var catAndSubCatDict = NSDictionary()
var catAndSubCatDict = Dictionary<Category, Array<SubCategory>>()
var catAndSubCatDict = [Category : Array<SubCategory>]()
var catAndSubCatDict = [Category : [SubCategory]]()

最后,使用swift词典,您可以使用类作为键 - 您需要做的是使键类(Category在您的代码中)实现Hashable和Equatable协议