快速从firebase检索到多个button3

我正在尝试从Firebase中检索数据，并将其显示到多个button和标签中。 检索后，我将其保存到字典中。 这是我的模型

import Foundation import Firebase class QuestionModel: NSObject { var CorrectAnswer: String! var Question: String! var optionA: String! var optionB: String! var optionC: String! init(snapshot: FIRDataSnapshot) { if let snapshotDict = snapshot.value as? Dictionary<String, Any> { CorrectAnswer = snapshotDict["CorrectAnswer"] as? String Question = snapshotDict["Question"] as? String optionA = snapshotDict["optionA"] as? String optionB = snapshotDict["optionB"] as? String optionC = snapshotDict["optionC"] as? String } } } 

我的JSON

我尝试了一些方法，但它返回给我零 。我认为非同步的火力点。

这是我的代码。

 import Foundation import UIKit import Firebase import FirebaseDatabase class AnsweringQuestionViewController: UIViewController { @IBOutlet weak var qLabel: UILabel! @IBOutlet weak var buttonA: UIButton! @IBOutlet weak var buttonB: UIButton! @IBOutlet weak var buttonC: UIButton! @IBOutlet weak var correctAnswer: UIButton! //var buttons: [UIButton]! thinking of using button tags? var ref: FIRDatabaseReference! var questionModel : [QuestionModel] = [] override func viewDidLoad(){ super.viewDidLoad() // FIRDatabase.database().persistenceEnabled = true ref = FIRDatabase.database().reference() db() } func db(){ ref.child("Science").observe(.value, with: { snapshot in for child in snapshot.children { let user = QuestionModel.init(snapshot: (child as? FIRDataSnapshot)!) self.questionModel.append(user) } self.qLabel.text = self.questionModel[0].Question self.buttonA.setTitle("\(self.questionModel[0].CorrectAnswer)", for: UIControlState.normal) }, withCancel: nil) } } 

裸露我的代码，我仍然在学习。 我不知道从哪里去显示我的数据到多个button，并确定哪个button被“点击”是CorrectAnwer。

如果你愿意的话，如果你能重新构build我的代码，那么我会非常高兴。 谢谢 ：）

Answer 1

尝试这个…

 import FirebaseDatabase class Question { var correctAnswer: String? var question: String? var optionA: String? var optionB: String? var optionC: String? init(snapshot: FIRDataSnapshot){ if let snap = snapshot.value as? [String: String] { correctAnswer = snap["CorrectAnswer"] question = snap["Question"] optionA = snap["OptionA"] optionB = snap["OptionB"] optionC = snap["OptionC"] } } } import FirebaseDatabase import UIKit class ViewController: UIViewController { @IBOutlet weak var qLabel: UILabel! @IBOutlet weak var buttonA: UIButton! @IBOutlet weak var buttonB: UIButton! @IBOutlet weak var buttonC: UIButton! @IBOutlet weak var correctAnswer: UIButton! var fireRootRef: FIRDatabaseReference! var questions = [Question]() override func viewDidLoad() { super.viewDidLoad() fireRootRef = FIRDatabase.database().reference() fetchQuestions(inCategory: "Science") } func fetchQuestions(inCategory category: String){ let questionsRef = fireRootRef.child(category) questionsRef.observe(.value, with: {(snapshot)-> Void in var allQuestions = [Question]() for child in snapshot.children { allQuestions.append(Question(snapshot: child as! FIRDataSnapshot)) } self.questions = allQuestions self.reloadUI(withQuestions: self.questions) }) } func reloadUI(withQuestions questions: [Question]){ guard questions.count > 0 else {return} if let answerToQuestion1 = questions[0].correctAnswer, let wrongAnswer = questions[0].optionA, let wrongAnswer2 = questions[0].optionB, let wrongAnswer3 = questions[0].optionC { let randomOrderedAnswers = [answerToQuestion1, wrongAnswer, wrongAnswer2, wrongAnswer3].shuffled() buttonA.setTitle(randomOrderedAnswers[0], for: .normal) buttonB.setTitle(randomOrderedAnswers[1], for: .normal) buttonC.setTitle(randomOrderedAnswers[2], for: .normal) correctAnswer.setTitle(randomOrderedAnswers[3], for: .normal)//keep in mind the correctAnswer label wont always contain the actual correct answer now } else { print("failed to get value for one of the answes options") } if let questionText = questions[0].question { qLabel.text = questionText } else { qLabel.text = "failed to get question text" } } } extension MutableCollection where Indices.Iterator.Element == Index { /// Shuffles the contents of this collection. mutating func shuffle() { let c = count guard c > 1 else { return } for (firstUnshuffled , unshuffledCount) in zip(indices, stride(from: c, to: 1, by: -1)) { let d: IndexDistance = numericCast(arc4random_uniform(numericCast(unshuffledCount))) guard d != 0 else { continue } let i = index(firstUnshuffled, offsetBy: d) swap(&self[firstUnshuffled], &self[i]) } } } extension Sequence { /// Returns an array with the contents of this sequence, shuffled. func shuffled() -> [Iterator.Element] { var result = Array(self) result.shuffle() return result } } 

更新我已经添加了扩展，使您可以随机播放数组中的元素顺序，以便您可以“随机”设置答案标签，正确的答案不总是在同一个地方。 这个扩展是由@NateCook在这里提出的

要知道是否select了正确答案，只需检查所选button的文本是否为问题的correctAnswer属性，例如if buttonA.title(for: .normal)! == questions[0].correctAnswer {print("correct answer selected)"} if buttonA.title(for: .normal)! == questions[0].correctAnswer {print("correct answer selected)"} 。 只要确保解压缩buttonA.title(for: .normal)的可选值buttonA.title(for: .normal)否则它会在它之前有“可选”一词，因此不会完全等于正确的答案文本