ios - 将内容从 Firebase 拉入 Swift 的问题

Question

我正试图从 Firebase 获取报价，但我很挣扎。当然，我也不知道我在做什么。我需要一些帮助!

在 Firebase 中，我的报价设置如下:

root --> quotes --> quoteID --> quoteText, quoteAttribution

我正在尝试从 Firebase 中提取引号，将它们添加到本地数组(稍后放入字典)，然后随机提取一个以在应用程序中使用。我希望将quoteText放入quoteLabel.text，将quoteAttribution放入authorLabel.text。我在另一个 StackOverflow 问题中找到了这个解决方案，但它在第 43 行抛出以下错误:

Could not cast value of type 'NSNull' (0x10f549740) to 'NSDictionary' (0x10f549178). 2018-07-21 22:49:50.241473-0400 Wavefully[72475:1126119] Could not cast value of type 'NSNull' (0x10f549740) to 'NSDictionary' (0x10f549178).

对于如何从 Firebase 中提取 quoteText 和 quoteAttribution 以在我的应用程序中使用，是否有人有任何提示？

---

这是我的代码:

class ViewController: UIViewController {

class quoteClass {
    var uid = ""
    var quote = ""
    var author = ""
}

@IBOutlet weak var quoteLabel: UILabel!
@IBOutlet weak var authorLabel: UILabel!

var ref: DatabaseReference?
var databaseHandler: DatabaseHandle?

var quotesArray = [quoteClass]()

override func viewDidLoad() {
    super.viewDidLoad()

    // Set the reference to Firebase
    ref = Database.database().reference()

    let quotesRef = ref?.child("quotes")
    quotesRef?.observeSingleEvent(of: .value, with: { (snapshot) in
        for _ in snapshot.children {
            let quoteSnap = snapshot
            let quoteKey = quoteSnap.key

            let thisQuoteRef = quotesRef?.child("quoteID")
            thisQuoteRef?.observeSingleEvent(of: .value, with: { (quoteSnap) in
                let singlequoteSnap = quoteSnap
                let quoteDict = singlequoteSnap.value as! [String:AnyObject]
                let quote = quoteDict["quoteText"]
                let author = quoteDict["quoteAttribution"]

                let aQuote = quoteClass()
                aQuote.uid = quoteKey
                aQuote.quote = quote as! String
                aQuote.author = author as! String

                print(aQuote.quote)
                print(aQuote.author)
                print(aQuote.uid)

                self.quotesArray.append(aQuote)
            })
        }
    })

    let singleQuote = quotesArray.randomItem()!
    print(singleQuote.uid)
    print(singleQuote.quote)
    print(singleQuote.author)}}

---

非常感谢您的帮助!

Answer 1

或者，您也可以通过将数据转换为 NSDictionary 来使用您的数据，如下所示:

        let dictionary = snapshot.value as? NSDictionary
        let quote = dictionary["quoteText"] as? String ?? ""