Swift 检索 Firebase 数据 [英] Swift Retreive Firebase data

问题描述

Firebase 数据库中的以下数据:

The following data in the Firebase Database:

{
  "schedule": {
      "Week 1": {
        "active": "true"
      },
      "Week 2": {
        "active": "true"
      },
      "Week 3": {
        "active": "false"
      },
      "Week 4": {
        "active": "true"
      },  
      ...
   }
}

我想检索只有 active 为 true 的所有周.我正在设置 Firebase 参考:

I want to retrieve all the Weeks where the active is true only. I am setting the Firebase reference as such:

ref = FIRDatabase.database().reference(withPath: "Schedule")

然后执行以下操作:

ref.observeSingleEvent(of: .value, with: { snapshot in
        //
        print("Count: ", snapshot.childrenCount)

        for _ in snapshot.children {
                print("(snapshot.value)")
        }

    })

产生以下输出:

Optional({
      "Week 1" =     {
           active = 1;
       };
       "Week 2" =     {
           active = 1;
       };
       "Week 3" =     {
           active = 0;
       };
       "Week 4" =     {
           active = 1;
       };
       ...
}

有人可以建议我如何才能获得 active 设置为 true 需要加载到字符串类型数组中的几周:

Can someone please suggest how I can get just the weeks where active is set to true which needs to be loaded in an array of type string :

var weeksActive = [String]()

推荐答案

为此，您可以像这样使用 queryOrdered(byChild:) 和 queryEqual(toValue:).

For that you can use queryOrdered(byChild:) and queryEqual(toValue:) like this.

let ref = FIRDatabase.database().reference(withPath: "Schedule").queryOrdered(byChild: "active").queryEqual(toValue : true)

ref.observe(.value, with:{ (snapshot) in

    print("Count: ", snapshot.childrenCount)
    for child in snapshot.children {
        print("((child as! FIRDataSnapshot).value)")
        //To get week you need to access key
        print("((child as! FIRDataSnapshot).key)")
    }
})

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