ios - 如何知道附加函数是否正在填充 NSObject 的属性

Question

swift 2.0 Alamofire 2.0 Xcode 7 IOS 9

我有下一个函数调用 API 并以 JSON 格式检索 friend 列表，转换字典中的列表并将其附加到 Friendship NSObject

func GetFriends(completionHandler: ([FriendShip]?, NSError?) -> ()) {

    Alamofire.request(Router.GetFriends(Test().getUserId())).responseJSON { (_, _, result) in

      var friends = [FriendShip]()

      switch result {
        case .Success(let json):
          if let responseObject = json as? [String: AnyObject], let hits = responseObject["hits"] as? [[String: AnyObject]] {
            for dictionary in hits {
              friends.append(FriendShip(dictionary: dictionary))
              print(friends)
            }
            completionHandler(friends, nil)
          }
        case .Failure(_, let error):
          completionHandler(nil, error as NSError)
      }

    }

print(dictionary) 的结果是:

["_id": 546a6ef98e6df97032266, "friend": {
    "_id" = 546a4b3e1f8d2c2630dd2;
    name = "Daniela";
    profileImageUrl = "https://api-static/profile/546a4b3e1f8d2c2630dd2.1.jpg";
    statusTxt = "";
}]
["_id": 546a6f988e6df97032266, "friend": {
    "_id" = 546a4ba51f8d2c2630dd2;
    name = "Mara";
    profileImageUrl = "https://api-static/profile/546a4ba51f8d2c2630dd2.1.jpg";
    statusTxt = undefined;
}]
["_id": 546a70a18e6df97032266, "friend": {
    "_id" = 546a4bd61f8d2c2630dd2;
    name = "Alejandro";
    profileImageUrl = "https://api-static/profile/546a4bd61f8d2c2630dd2.1.jpg";
    statusTxt = "Marty";
}]
["_id": 546a715d8e6df97032266, "friend": {
    "_id" = 546a4be01f8d2c2630dd2;
    name = "Pedro";
    profileImageUrl = "https://api-static/profile/546a4be01f8d2c2630dd1.1.jpg";
}]

类友谊和用户

 class FriendShip: NSObject{

      var id: String?
      var userId: String?
      var user: User?
      var friendId: String?
      var friend: User?
      var date: NSDate?

      init(dictionary: [String: AnyObject]){

        id        = dictionary["id"] as? String
        userId    = dictionary["userId"] as? String
        user      = dictionary["user"] as? User
        friendId  = dictionary["friendId"] as? String
        friend    = dictionary["friend"] as? User
        date      = dictionary["date"] as? NSDate

      }

      override var description : String {
        let friendString = friend!.name != nil ? friend!.name! : "nil"
        let urlString = friend!.profileImageUrl != nil ? friend!.profileImageUrl! : "nil"
        return "Friendship:\nfriend = \(friendString),\nurlString = \(urlString)"
      }
}

class User: NSObject{

      var id: String?
      var name: String?
      var statusTxt: String?
      var profileImageUrl: String?

      init(dictionary: [String: AnyObject]){

        id              = dictionary["id"] as? String
        name            = dictionary["name"] as? String
        statusTxt       = dictionary["statusTxt"] as? String
        profileImageUrl = dictionary["profileImageUrl"] as? String
      }

      override var description : String {
        let nameString = name != nil ? name! : "nil"
        let profileImageUrlString = profileImageUrl != nil ? profileImageUrl! : "nil"
        return "Friendship:\nname = \(nameString),\nprofileImageUrl = \(profileImageUrlString)"
      }

}

我如何知道/查看/打印 friends.append 函数是否正常工作以及它填充 OK Friendship NSObject 的所有属性？

Answer 1

如果我对你的理解正确，你需要一种方法来打印/调试你的Friendship类的内容。

NSObject 实现了 NSObjectProtocol，它有一个计算属性 description。该属性返回一个表示类内容的字符串。它是您打印对象时看到的文本。所以你的 Friendship 类已经从 NSObject 继承了这个 description 协议(protocol)。但在您的情况下，它只打印类名，因为这是默认实现。

所以如果你想对你的类有一个更有意义的描述，你必须重写 description 属性:

class Friendship: NSObject {
    var name: String?
    var age: Int?

    override var description : String {
        let nameString = name != nil ? name! : "nil"
        let ageString = age != nil ? String(age!) : "nil"
        return "Friendship:\nname = \(nameString),\nage = \(ageString)"
    }
}

我不知道您的实际 Friendship 类是什么样的，所以我创建了自己的非常简单的类，它只包含一个名字和一个年龄。

所以现在当您有 2 个 Friendship 实例(一个填充一个空)并打印它们时，您可以看到这些对象的内容:

let friendship1 = Friendship()
friendship1.name = "John"
friendship1.age = 34
print(friendship1)

let friendship2 = Friendship()
print(friendship2)

打印:

Friendship:
name = John,
age = 34

Friendship:
name = nil,
age = nil

更新

在您的情况下，覆盖的描述变量应如下所示:

    class FriendShip: NSObject{

    var id: String?
    var userId: String?
    var user: User?
    var friendId: String?
    var friend: User?
    var date: NSDate?

    init(dictionary: [String: AnyObject]){ 
        id        = dictionary["id"] as? String
        userId    = dictionary["userId"] as? String
        user      = dictionary["user"] as? User
        friendId  = dictionary["friendId"] as? String
        friend    = dictionary["friend"] as? User
        date      = dictionary["date"] as? NSDate

    }

    override var description : String {
        let friendDescription = friend != nil ? friend!.description : "nil"
        let userIdString = userId != nil ? userId! : "nil"
        return "Friendship:\nfriend = \(friendDescription),\nuserId = \(userIdString)"
    }
}

class User: NSObject{

    var id: String?
    var name: String?
    var statusTxt: String?
    var profileImageUrl: String?

    init(dictionary: [String: AnyObject]) {  
        id              = dictionary["id"] as? String
        name            = dictionary["name"] as? String
        statusTxt       = dictionary["statusTxt"] as? String
        profileImageUrl = dictionary["profileImageUrl"] as? String
    }

    override var description : String {
        let nameString = name != nil ? name! : "nil"
        let profileImageUrlString = profileImageUrl != nil ? profileImageUrl! : "nil"
        return "User:\nname = \(nameString),\nprofileImageUrl = \(profileImageUrlString)"
    }
}

你可以测试一下:

// test empty object
let friendship = FriendShip(dictionary: [String: AnyObject]())
print(friendship.description)

// test correct object
let user = User(dictionary: ["name": "John", "profileImageUrl": "http://image.com"])
let friendship2 = FriendShip(dictionary: ["friend": user, "userId": "1"])
print(friendship2.description)

打印

Friendship:
friend = nil,
userId = nil

Friendship:
friend = User:
name = John,
profileImageUrl = http://image.com,
userId = 1