Ios 为什么字典是零?
这是我正在进行错误帮助的代码Ios 为什么字典是零?,ios,swift,nsdictionary,Ios,Swift,Nsdictionary,这是我正在进行错误帮助的代码 for result in (result2 ){ var dictData: NSDictionary? dictData?.setValue(result.valueForKey("offer_title") as? String, forKey:"offer_title") print(result.valueForKey("offer_title") as?
for result in (result2 ){
var dictData: NSDictionary?
dictData?.setValue(result.valueForKey("offer_title") as? String, forKey:"offer_title")
print(result.valueForKey("offer_title") as? String)
if result.valueForKey("discountPercentageOff") as? String != "" {
dictData?.setValue(result.valueForKey("discountPercentageOff") as? String, forKey:"discountPercentageOff")
print(result.valueForKey("discountPercentageOff") as? String)
}
dictData?.setValue(result.valueForKey("is_booked") as? Bool, forKey:"is_booked")
print(result.valueForKey("is_booked"))
dictData?.setValue(result.valueForKey("is_saved") as? Bool, forKey:"is_saved")
print(result.valueForKey("is_saved"))
dictData?.setValue(result.valueForKey("area_id") as? String, forKey:"area_id")
print(result.valueForKey("area_id"))
dictData?.setValue(result.valueForKey("area_name") as? String, forKey:"area_name")
dictData?.setValue(result.valueForKey("business_id") as? String, forKey:"business_id")
dictData?.setValue(result.valueForKey("business_name") as? String, forKey:"business_name")
dictData?.setValue(result.valueForKey("category_id") as? String, forKey:"category_id")
dictData?.setValue(result.valueForKey("category_name") as? String, forKey:"category_name")
dictData?.setValue(result.valueForKey("expiry_date") as? String, forKey:"expiry_date")
dictData?.setValue(result.valueForKey("featured") as? String, forKey:"featured")
dictData?.setValue(result.valueForKey("locality") as? String, forKey:"locality")
dictData?.setValue(result.valueForKey("offer_available") as? String, forKey:"offer_available")
dictData?.setValue(result.valueForKey("offer_id") as? String, forKey:"offer_id")
dictData?.setValue(result.valueForKey("offer_image") as? String, forKey:"offer_image")
dictData?.setValue(result.valueForKey("offer_nature") as? String, forKey:"offer_nature")
dictData?.setValue(result.valueForKey("offerNatureValue") as? String, forKey:"offerNatureValue")
dictData?.setValue(result.valueForKey("on_going") as? Bool, forKey:"on_going")
dictData?.setValue(result.valueForKey("discountOriginalPrice") as? String, forKey:"discountOriginalPrice")
dictData?.setValue(result.valueForKey("discountDiscountedPrice") as? String, forKey:"discountDiscountedPrice")
let offer = Offer()
offer.setDatafromServer(dictData!)
self.saveOfferData(item as! NSDictionary)
print("item:\(dictData)")
self._featuredOfferArray.addObject(offer)
self.feturedOfferTableView.reloadData()
}
当我将nsdictionary作为参数传递时,它会给出可选的错误nil,您可以看到我创建了nsdictionary的每个循环。但它仍然是零。我不明白 您从不初始化字典,
var dictData:NSDictionary?
只定义变量的类型。此外,如果您想更改字典,它必须是可变的
首先:
var dictData: NSMutableDictionary? = NSMutableDictionary()
把这行改成
var dictData = NSMutableDictionary();
失败的原因是字典根本没有初始化 Swift本机类型有一个更简单的语法,实际上不需要任何类型转换,因为您只是复制
AnyObject
项。如果任何值为nil
,则不设置键
for result in result2 {
var dictData = [String:AnyObject]()
dictData["offer_title"] = result["offer_title"]
dictData["discountPercentageOff"] = result["discountPercentageOff"]
...
甚至复制整个字典(在Swift中,由于值语义,没有问题)而且删除未使用的键更有效。您需要声明一个NSMutableDictionary而不是NSDictionary
NSDictionary
是不可变的。我没有看到任何结果。我看到您在哪里声明了对NSDictionary
的引用,但没有看到您在哪里创建的引用。为什么要创建一个包含非可选数据的可选字典??原因是NSDictionary
是不可变的,并且您从未初始化过字典。使用本机Swift字典和密钥订阅,您可以免费获得可变性。并停止使用setValue:forKey:
,除非您知道(并且需要)特殊行为。
for result in result2 {
var dictData = [String:AnyObject]()
dictData["offer_title"] = result["offer_title"]
dictData["discountPercentageOff"] = result["discountPercentageOff"]
...