Question

我在从Firebase获取数据时遇到问题。

架构是

{
    title: "dog",
    images: {
        main: "dog.png",
        others: {
            0: "1.png",
            1: "2.png",
            2: "3.png"
        }
    }
}

如何将FDataSnapshot解析为swift模型？

Answer 1

Firebase是NoSQL JSON数据库，没有架构，也没有表。数据存储在＆＃39;树中。节点结构;父母和孩子。

您不需要解析Firebase JSON数据来访问它，您可以直接访问它。

FDataSnapshots包含.key，它是Firebase和.value中的父键。 .Value可能包含一个节点或多个节点。 Value将具有表示快照中数据的键：值对

因此，对于您的示例，您将拥有像此一样的Firebase结构

select column_value from table(mc.Get_REFTYPES@READ_MAIN_MCNAV(param1, param2, param3)));

所以，假设你想一次一个地读取每个dog_id_x节点并打印一些值。

CREATE OR REPLACE FUNCTION "MC"."Get_REFTYPES"(
  param1 IN VARCHAR, 
  param2  IN NUMBER, 
  param3  IN DATE DEFAULT SYSDATE
  )
  RETURN RefType_T PIPELINED IS

  CURSOR cur_st (
    cur_param1 VARCHAR, 
    cur_param2  NUMBER,
    cur_param3  DATE
    ) IS
            select 
              TypeID
            FROM ......
          WHERE......... ;

  t_st Types_T;  -- Table variable to store return values       

 BEGIN

    OPEN cur_st(param1, param2 , param3 );
    FETCH cur_st BULK COLLECT INTO t_st;
    CLOSE cur_st;

    FOR i IN 1..t_st.COUNT LOOP
            PIPE ROW(t_st(i));
    END LOOP;
    RETURN;
END;

这将输出

dogs
  dog_id_0
    title: "dog"
    type: "Alaskan Malamute"
    images:
        main: "dog.png"
        others:
            0: "1.png"
            1: "2.png"
  dog_id_1
    title: "another dog"
    type: "Boxer"
    images:
        main: "another_dog.png"
        others:
            0: "3.png"
            1: "4.png"

dog_id_0和dog_id_1是使用Firebase childByAutoId创建的节点名称。

您可以轻松创建Dog类，并将其传递给FDataSnapshot，它将从快照中的数据填充该类。

Answer 2

2017年2月更新，Swift 3 Xcode 8

由于Swift3和Firebase的许多内容在提出此问题时已发生变化，因此我将提供解析Firebase数据的更新方法：

    let userID = FIRAuth.auth()?.currentUser?.uid

    //I am registering to listen to a specific answer to appear
    self.ref.child("queryResponse").child(userID!).observeSingleEvent(of: .value, with: { (snapshot) in
        //in my case the answer is of type array so I can cast it like this, should also work with NSDictionary or NSNumber
        if let snapshotValue = snapshot.value as? NSArray{
            //then I iterate over the values
            for snapDict in snapshotValue{
                //and I cast the objects to swift Dictionaries
                let dict = snapDict as! Dictionary<String, Any>
            }
        }
    }) { (error) in
        print(error.localizedDescription)
    }

Answer 3

您可以使用Dictionary手动解析它，也可以使用我的library。

您案例的示例代码：

func main(){
    let root=SnapshotParser().parse(snap: Snapshot, type: Root.self)
}

class Root: ParsableObject {
    var title:String?=nil
    var images:Images?=nil

    required init(){}

    func bindProperties(binder: SnapshotParser.Binder) {
        binder.bindField(name: "title", field: &title)
        binder.bindObject(name: "images", field: &images)
    }
}

class Images: ParsableObject {
    var main:String?=nil
    var others:[Int:String]?=nil

    required init(){}

    func bindProperties(binder: SnapshotParser.Binder) {
        binder.bindField(name: "main", field: &main)
        binder.bindDictionary(name: "others", dict: &others)
    }
}

Answer 4

尝试玩这个：

func makeItems(from snapshot: DataSnapshot) -> [SimpleItem] {
        var items = [SimpleItem]()
        if let snapshots = snapshot.children.allObjects as? [DataSnapshot] {
            for snap in snapshots {
                if let postDictionary = snap.value as? Dictionary<String, AnyObject> {
                    let item = SimpleItem(parentKey: snap.key, dictionary: postDictionary)
                    items.append(item)
                }
            }
        }
    return items
}

func loadItems() {
    firebaseService.databaseReference
        .child("items")
        .queryOrdered(byChild: "date")
        .queryLimited(toLast: 5)
        .observeSingleEvent(of: .value) { snapshot in
            let items = self.makeItems(from: snapshot)
            print(" \(items)")
    }
}

class SimpleItem {
    var parentKey: String?

    var id: String?
    var description: String?

    init(parentKey: String, dictionary: [String : AnyObject]) {
        self.parentKey = parentKey

        id = dictionary["id"] as? String
        description = dictionary["description"] as? String
    }
}

Answer 5

这将解析单个对象中的所有快照子级并将其转换为数组，您可以轻松地解析具有索引的子级数组

if let snap = snapshot.children.allObjects as? [DataSnapshot]{
    print(snap)

    for (index,val) in snap.enumerated(){
        print("values")
        print(val)
        print(val.value)

    }
}

如何在swift

5 个答案: