Swift + Firebase：使用查詢向服務器隨機挑選一組對象

Question

我正在使用Swift爲iOS創建測驗應用程序，並將Firebase用作後端。我希望能夠提出一個查詢，挑選10個隨機問題並將其返回。

Answer 1

一切爲我的答案，你需要給每一個問題像這樣的價值首先：

{ 
     "question1": { 
     "question" : "Do you know swift", 
     "answer" : "Nope", 
     "value": 1 
     }, 
     "question2": { 
     "question" : "Do you know firebase", 
     "answer" : "A bit", 
     "value" : 2 
     } 
    } 

之後，我們建議在你的火力規則（firebase docs）這樣添加一個索引：

{ 
     "rules": { 
     "questions": { 
      ".indexOn": ["value"] 
     } 
     } 
    } 

接下來是迅速的部分：

//Use a for loop to get 10 questions 
for _ in 1...10{ 
    //generate a random number between 1 and the amount of questions you have 
    var randomNumber = Int(arc4random_uniform(amountOfQuestions - 1)) + 1 

    //The reference to your questions in firebase (this is an example from firebase itself) 
    let ref = Firebase(url: "https://dinosaur-facts.firebaseio.com/dinosaurs") 
    //Order the questions on their value and get the one that has the random value 
    ref.queryOrderedByChild("value").queryEqualToValue(randomNumber) 
    .observeEventType(.ChildAdded, withBlock: { 
     snapshot in 
     //Do something with the question 
     println(snapshot.key) 
    }) 
} 

實際SWIFT代碼可能存在缺陷，並針對具體的火力點代碼看看Ios documentation