swift - 初始化类对象 swift 3

Question

我在初始化某个类的对象时遇到问题。这有什么问题？ (我可以上传我所有的代码，但如果需要的话它会很大)

编辑:我的 View Controller 代码:

    import UIKit

class ViewController: UIViewController{

@IBOutlet weak var questionLabel: UILabel!
@IBOutlet weak var answerStackView: UIStackView!

// Feedback screen
@IBOutlet weak var resultView: UIView!
@IBOutlet weak var dimView: UIView!
@IBOutlet weak var resultLabel: UILabel!
@IBOutlet weak var feedbackLabel: UILabel!
@IBOutlet weak var resultButton: UIButton!

@IBOutlet weak var resultViewBottomConstraint: NSLayoutConstraint!
@IBOutlet weak var resultViewTopConstraint: NSLayoutConstraint!

var currentQuestion:Question?

let model = QuizModel()
var questions = [Question]()

var numberCorrect = 0

override func viewDidLoad() {
    super.viewDidLoad()
    model.getQuestions()
}

override init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: Bundle?) {
    super.init(nibName: nil, bundle: nil)
}

required init?(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
}


func setAll(questionsReturned:[Question]) {
    /*
    // Do any additional setup after loading the view, typically from a nib.

    // Hide feedback screen
    dimView.alpha = 0

    // Call get questions
    questions = questionsReturned

    // Check if there are questions
    if questions.count > 0 {

        currentQuestion = questions[0]

        // Load state
        loadState()

        // Display the current question
        displayCurrentQuestion()
    }
*/
print("Called!")

}


override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

我的 QuizModel 代码:

 import UIKit
 import FirebaseDatabase


class QuizModel: NSObject {

override init() {
    super.init()
}

var ref:FIRDatabaseReference?
var test = [[String:Any]]()
var questions = [Question]()
weak var prot:UIPageViewControllerDelegate?
var first = ViewController()

func getQuestions(){
  getRemoteJsonFile()
}


func pars(){


    /*let array = test
    var questions = [Question]()

    // Parse dictionaries into Question objects
    for dict in array {

        // Create question object
        let q = Question()

        // Assign question properties
        q.questionText = dict["question"] as! String
        q.answers = dict["answers"] as! [String]
        q.correctAnswerIndex = dict["correctIndex"] as! Int
        q.module = dict["module"] as! Int
        q.lesson = dict["lesson"] as! Int
        q.feedback = dict["feedback"] as! String

        // Add the question object into the array
        questions += [q]
    }
    */

    //Protocol setAll function
    first.setAll(questionsReturned: questions)
}

func getRemoteJsonFile(){

    ref = FIRDatabase.database().reference()

    ref?.child("Quiz").observeSingleEvent(of: .value, with: { (snapchot) in

        print("hey")
        let value = snapchot.value as? [[String:Any]]
        if let dict = value {
            self.test = dict
            self.pars()
        }
    })
}

这不是我的全部代码，但我认为这是最重要的部分。在 QuizModel 代码中，我将我的代码从获取 json 文件重新设置为从 firebase 获取数据，这样你就可以看到像“getRemoteJSONFile”这样的函数名称，并且在解析函数中解析 json，但这不是我的问题，我认为

Answer 1

看起来您在初始化常量所在的 viewController 之前尝试初始化常量。您必须将其设为 var 并在 viewDidLoad 中对其进行初始化>(或其他生命周期方法)，或将其设为 lazy var 并在首次访问时对其进行初始化。