Question

我在firebase中有三个节点，我想使用相同的循环循环。我已成功使用此代码遍历单个节点（cookie）：

databaseRef.child("cookies").observeSingleEvent(of: .value, with: {(snapshot) in
         for item in snapshot.children.allObjects as! [DataSnapshot] {
            let thisItem = item.value as! NSDictionary

            if(favoriteArray.contains(item.key)) {

             self.numberOfRecipes.append(thisItem["recipeHeaderFirebase"] as! String)

             let tempRecipe = Recipe()
             tempRecipe.fbKey = item.key
             tempRecipe.recipeHeaderObject = (thisItem["recipeHeaderFirebase"] as! String)
             tempRecipe.recipeTextObject = (thisItem["recipeIngredientsTextFirebase"] as! String)
             tempRecipe.recipeImageObject = (thisItem["recipeImageFirebase"] as! String)

             self.recipeClassArray.append(tempRecipe)
         }   
    }
})

我现在想要循环其余两个节点。任何想法？

我尝试添加其他节点，但控制台中的打印显示它仅从最后一个节点添加。请参阅以下代码：

     self.databaseRef.child("cookies").observeSingleEvent(of: .value, with: {(snapshot) in
        self.databaseRef.child("dessert").observeSingleEvent(of: .value, with: {(snapshot) in self.databaseRef.child("breakfast").observeSingleEvent(of: .value, with: {(snapshot) in
         for item in snapshot.children.allObjects as! [DataSnapshot] {
            let thisItem = item.value as! NSDictionary

            if(favoriteArray.contains(item.key)) {

             self.numberOfRecipes.append(thisItem["recipeHeaderFirebase"] as! String)

             let tempRecipe = Recipe()
             tempRecipe.fbKey = item.key
             tempRecipe.recipeHeaderObject = (thisItem["recipeHeaderFirebase"] as! String)
             tempRecipe.recipeTextObject = (thisItem["recipeIngredientsTextFirebase"] as! String)
             tempRecipe.recipeImageObject = (thisItem["recipeImageFirebase"] as! String)

             self.recipeClassArray.append(tempRecipe)
         }

    }
        print(self.numberOfRecipes.count)
            print(self.recipeClassArray)

            let url = URL(string: self.recipeClassArray[self.currentView].recipeImageObject)
            self.recipeImageUI.kf.setImage(with: url)           //SÄTTER IN BILD MED KINGFISHER

            self.recipeHeader.text = self.recipeClassArray[self.currentView].recipeHeaderObject //SÄTTER IN HEADER

            self.ingredientText.text = self.recipeClassArray[self.currentView].recipeTextObject //SÄTTER IN TEXTEN


            self.animateFunc(image: self.recipeImageUI, labelHeader: self.recipeHeader, labelText: self.ingredientText) //FUNKTION FÖR ATT ANIMERA     
    }) 
  })  
})

Answer 1

以下代码打印所有三个级别的快照。我希望这会有所帮助：

self.databaseRef.child("cookies").observeSingleEvent(of: .value, with: { (cookiesSnapshot) in
    print("cookies snapshot: \(cookiesSnapshot)")

    self.databaseRef.child("dessert").observeSingleEvent(of: .value, with: { (dessertSnapshot) in 
        print("dessert snapshot: \(dessertSnapshot)")

        self.databaseRef.child("breakfast").observeSingleEvent(of: .value, with: { (breakfastSnapshot) in
            print("breakfast snapshot: \(breakfastSnapshot)")
        })
    })
})

我无法检查这一点，所以我希望所有}和}都在正确的位置。：）

Answer 2

您可以将快照转换为dict并循环显示dict：

databaseRef.child("cookies").observeSingleEvent(of: .value, with: { snapshot in
    if let dict = snapshot.value as? Dictionary<String, Dictionary<String, Any>> {
        for (key, value) in dict {
            if let recipeHeader = value["recipeHeaderFirebase"] as? String, favoriteArray.contains(key) {
                self.numberOfRecipes.append(recipeHeader)
             ...
            }
        }
    }
}

或者您可以使用枚举器：

databaseRef.child("cookies").observeSingleEvent(of: .value, with: { snapshot in
    let enumerator = snapshot.children
    while let (key, value) = enumerator.nextObject() as? FIRDataSnapshot {
        if let recipeHeader = value["recipeHeaderFirebase"] as? String, favoriteArray.contains(key) {
            self.numberOfRecipes.append(recipeHeader)
            ...
        }
    }
}

如何在同一循环中一次循环所有Firebase子项？

2 个答案: