Alle Benutzer das gleiche Kind in Firebase (Swift)

Question

Ich erstelle derzeit eine App in Firebase und ich möchte alle Benutzer Ananas Rate zu bekommen.

Dies ist der Baum:

user1: uid1 { 
    fruits: { 
    apple: 3 
    pineapple: 5 
    } 
} 

user2: uid2 { 
    fruits: { 
    apple: 4 
    pineapple: 2 
    } 
} 

ich diesen Code versucht:

var ref = FIRDatabase.database().reference() 
ref.queryOrderedByChild("fruits") 
      .observeSingleEventOfType(.Value, withBlock: { (snapshot) in 
       if (snapshot.value is NSNull) { 
        print("not found") 
       } else { 
        for child in snapshot.children { 
         let rate = child.value["pineapple"] as! String 
         print(rate) 
        } 
       } 
      }) 

Aber es gibt mir einen Fehler Nil von auszupacken.

Bild des structre:

Answer 1

Dies soll wie diese

var ref = FIRDatabase.database().reference() 
    ref.queryOrderedByChild("user2") 
     .observeSingleEventOfType(.Value, withBlock: { (snapshot) in 
      if snapshot.exists() { 
       for child in (snapshot.value?.allValues)! { 
        if let fruits = child["Fruits"] as? [String:String]{ 
         let rate = fruits["pineapple"] 
         print(rate) 
        } 
       } 
      } 
     }) 

Answer 2

Es scheint, dies braucht nur eine tiefe Abfrage sein?

let ref = self.myRootRef.child("parent_node") 

    ref.queryOrderedByChild("Fruits/pineapple").observeSingleEventOfType(.Value, withBlock: { 
     snapshot in 

     if (snapshot.value is NSNull) { 
      print("not found") 
     } else { 
      for child in snapshot.children { 

       let key = child.key as String 
       let dict = child.value["Fruits"] as! NSDictionary 
       let pineapple_count = dict["pineapple"] as! Int 
       print("key = \(key) count = \(pineapple_count)") 

      } 
     } 
    }) 

und der Ausgang ist

key = uid_1 count = 1 
key = uid_0 count = 3 
key = uid_2 count = 21 

Answer 3

unter diesen Code ausprobieren (Xcode 8.3.3, Swift 3 und Firebase 3)

var ref = Database.database().reference().child("fruits") 

    ref.observeSingleEvent(of: .value, with: {     
       (snapshot) in 
     if let fruitPost = snapshot.value as? Dictionary<String,AnyObject> { 
       for(key, value) in fruitPost { 
         if let fruitData = value as? Dictionary<String,AnyObject> { 
          if let fruits = fruitData["pineapple"] as? String{ 
            let rate = fruits 
             print(rate) 
            }    
           } 
          } 
        } 

Goodluck Kumpel!