Question

我遇到了尝试从firebase检索数据的问题。我一直收到一个错误，说NSObject在尝试追加时没有下标成员？目前firebase正在举行一个问题，一系列不同的答案和一个正确答案。

class QuestionList
{
//properties
public static var Username: String = ""
private static var quiz = [Question]()

static func getDummyQuestions()->[Question]
{
    //create some dummy data for the model
    var ref: FIRDatabaseReference!
    var refHandle: UInt!
    ref = FIRDatabase.database().reference() //reference

    refHandle = ref.child("Questions").child("Q1").observe(.value, with: { (snapshot)in
        let dataDict = snapshot.value as? NSObject

        //let value = snapshot.value as? NSDictionary
        //let quest = value?["Question"] as! String
        //let Answers = value?["Answers"] as! String
        //let Correct = value?["Correct"] as! String

        //quiz.append(Question(q: quest, a:[Answers], c: Correct))

        quiz.append(Question(q: dataDict["Question"], a: dataDict["Answers"], c: dataDict["Correct"]))


        //quiz.append(Question(q: "hello", a: ["short long", "short char", "short float", "short int"], c: 2 ))
        //quiz.append(Question(q: "bye", a: ["short short", "short int", "short float", "short int"], c: 2 ))


      print (dataDict)
    })
    return quiz
}

}

class Question
{
var quest:String
var answers:[String]
var correct:Int

init(q: String, a:[String], c:Int)
{
    quest = q
    answers = a
    correct = c
}

func isCorrectQuestion(itemSelected: String)->Bool {
    if (itemSelected == answers[correct]) {
        return true
    } else {
        return false
    }
}

} //}

Answer 1

将snapshot投射到字典：let dataDict = snapshot.value as? [String: Any]

refHandle = ref.child("Questions").child("Q1").observe(.value, with: { (snapshot)in
    if let dataDict = snapshot.value as? [String: Any] {

        if let quest = dataDict["Question"] as? String,
            let Answers = dataDict["Answers"] as? [String],
            let Correct = dataDict["Correct"] as? Int {
            quiz.append(Question(q: quest, a: Answers, c: Correct))
        }
    }

    print (dataDict)
})

NSObject没有下标成员

1 个答案: