除了显示所有用户的用户数据外，如何只显示喜欢已登录用户的人的数据？

Question

数据库

"people" : {
"9RYUttVhCzXKs6H1XnZ63TZ8Dun2" : {
  "Coordinates" : {
    "latitude" : 15.78583,
    "longitude" : -4.406417
  },
  "Education" : "CS",
  "PhotoPosts" : "https://firebasestorage.googleapis.com/v0/b/daylike-2f938.appspot.com/o/images%2FPhotoPosts?alt=media&token=65961f53-47f0-40f5-b990-02fc05ef94ad",
  "WhatIamConsideringBuying" : "Food",
  "caption" : 1563880684210,
  "likes" : 31,
  "peopleWhoLike" : {
    "-LkAU_XjMft_plwga-uw" : "NMNQYJ5z64fATK2MMs7m0ggHl0k2",
    "-LkAVL6rqnlATHsnMXix" : "NMNQYJ5z64fATK2MMs7m0ggHl0k2",
    "-LkAemFWYz4A1DkmTYrC" : "q3up6CyAe5PoEAooJwCclOGGcZd2",
    "-LkAfAIvWE9lB-Os0IYK" : "K1eqsVZfKGgIf0sS1UZcPNxY62x1",
    "-LkAgZNIsTlnuJzyOKO7" : "KRFfYoO8IwO1qiHknzP9wLCmUSp1",
    "-LkB5k0o89n2dFS6bUzH" : "KRFfYoO8IwO1qiHknzP9wLCmUSp1",
    "-LkB5k3USKvBZR62H6t8" : "KRFfYoO8IwO1qiHknzP9wLCmUSp1",
    "-LkBHsFvOxtc5M_eLisY" : "KRFfYoO8IwO1qiHknzP9wLCmUSp1",
    "-LkBQObubRDb1eY-L5ME" : "KRFfYoO8IwO1qiHknzP9wLCmUSp1",
    "-LkBRuvEb0KX20Blrhpq" : "NMNQYJ5z64fATK2MMs7m0ggHl0k2",
    "-LkBSSKYKEmtsT68w564" : "NMNQYJ5z64fATK2MMs7m0ggHl0k2",
    "-LkGPtRpz_AwBhA_4Mhx" : "NMNQYJ5z64fATK2MMs7m0ggHl0k2",
    "-LkGZA9t85w21219wPcZ" : "NMNQYJ5z64fATK2MMs7m0ggHl0k2",
    "-LkG_SwHgKvQ-4hIGzVC" : "NMNQYJ5z64fATK2MMs7m0ggHl0k2",
    "-LkG_ZLibLrGs2G62Pfr" : "NMNQYJ5z64fATK2MMs7m0ggHl0k2",
    "-LkG_sDlzzMp3phVceTW" : "NMNQYJ5z64fATK2MMs7m0ggHl0k2",
    "-LkGaKINLcD0j9_NtYa_" : "KRFfYoO8IwO1qiHknzP9wLCmUSp1",
    "-LkGd0JcyfHwQXPUPK0U" : "KRFfYoO8IwO1qiHknzP9wLCmUSp1",
    "-LkGdYuC1sGCUXpizo56" : "KRFfYoO8IwO1qiHknzP9wLCmUSp1",
    "-LkGdeN3mG3vpWVx3Jci" : "KRFfYoO8IwO1qiHknzP9wLCmUSp1",
    "-LkGdfjNR0dPPztJhUtr" : "KRFfYoO8IwO1qiHknzP9wLCmUSp1",
    "-LkGdfyOF3Rg7fgh1Noo" : "KRFfYoO8IwO1qiHknzP9wLCmUSp1",
    "-LkGdgJX7R-w8IB2ns50" : "KRFfYoO8IwO1qiHknzP9wLCmUSp1",
    "-LkP99lTiKk5tXamW5yW" : "KRFfYoO8IwO1qiHknzP9wLCmUSp1",
    "-LkP9YuvzkKIOmotFNSx" : "KRFfYoO8IwO1qiHknzP9wLCmUSp1",
    "-LkQw0h80_jSCYZs8mNu" : "NMNQYJ5z64fATK2MMs7m0ggHl0k2",
    "-LkT_bvTo8SlYTtJR12Q" : "KRFfYoO8IwO1qiHknzP9wLCmUSp1",
    "-LkThUcjHQWLUvQk4xKQ" : "KRFfYoO8IwO1qiHknzP9wLCmUSp1",
    "-LkYMJ4f6Cwy-OD0Ca-W" : "q3up6CyAe5PoEAooJwCclOGGcZd2",
    "-Lk_1YzFt-h0UPSNpp82" : "KRFfYoO8IwO1qiHknzP9wLCmUSp1",
    "-Lk_1_yh6dVzyCMv9ghS" : "KRFfYoO8IwO1qiHknzP9wLCmUSp1"
  },
  "postID" : "9RYUttVhCzXKs6H1XnZ63TZ8Dun2",
  "users" : "nane19@aol.com"
},

以上是数据库。 基本上，所有喜欢此人的用户都将显示其数据（照片等）。 喜欢的人会在他们喜欢的任何人中找到孩子。

我在下面的代码中添加了此行，该代码仅显示了所有用户的所有用户数据（照片等）：“ for thisUsersUid1中的thisUsersUid”

 let thisUsersUid = Auth.auth().currentUser?.uid //Mr. Dunn's uid
    let thisUsersUid1 = Database.database().reference().child("people").child(thisUsersUid!).child("peopleWhoLikedMe")

    ref = Database.database().reference().child("people");

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

        if snapshot.childrenCount>0{

            self.people.removeAll()

            /////This line describes what I want to do, but  I don't know how to write it in formal code : for thisUsersUid in thisUsersUid1 ////// {
            for people in snapshot.children.allObjects as! [DataSnapshot] {
                if people.key != thisUsersUid { //do not add this users info to the array
                let peopleObject = people.value as? [String: AnyObject]

                let peopleEducation = peopleObject?["Education"] as? String
                    let peopleWhatIamConsideringBuying = peopleObject?["WhatIamConsideringBuying"] as? String
                    let peoplePhotoPosts = peopleObject?["PhotoPosts"]  as? String
                    let peopleimageDownloadURL = peopleObject?["imageDownloadURL"] as? String
                    let peoplepostID = peopleObject?["postID"] as? String
                    let peoplepeopleWhoLike = peopleObject?["peopleWhoLike"] as? String

                    let peopl = Userx(Education: peopleEducation, WhatIamConsideringBuying: peopleWhatIamConsideringBuying, PhotoPosts: peoplePhotoPosts, imageDownloadURL: peopleimageDownloadURL, postID: peoplepostID, peopleWhoLike: peoplepeopleWhoLike)
                        self.people.append(peopl)
  }
                        self.table.reloadData()

这是使数据库引用peopleWhoLike的代码

     ref.child("people").child(self.postID).observeSingleEvent(of: .value, with:  {(snapshot) in

        if let people = snapshot.value as? [String: AnyObject] {
            let updateLikes: [String: Any] = ["peopleWhoLike/\(keyToPost)" : Auth.auth().currentUser!.uid]
            ref.child("people").child(self.postID).updateChildValues(updateLikes, withCompletionBlock: { (error, reff) in



                if error == nil {
                    ref.child("people").child(self.postID).observeSingleEvent(of: .value, with: { (snap) in
                        if let properties = snap.value as?[String: AnyObject]{
                            if let likes = properties["peopleWhoLike"] as? [String : AnyObject] {
                                let count = likes.count

                            let update = ["likes" : count]
                                ref.child("people").child(self.postID).updateChildValues(update)

最后，不是显示所有用户的数据，而是仅显示来自喜欢已登录用户的人员的数据。

///这是我基于杰伊的答案的代码

func printPersonInfo(uid: String) {
    let usersRef = Database.database().reference().child("people")
    let thisUser = usersRef.child(uid)
    thisUser.observeSingleEvent(of: .value, with: { snapshot in
        let education = snapshot.childSnapshot(forPath: "Education").value as? String ?? "No Education"
        let whatIamConsideringBuying = snapshot.childSnapshot(forPath: "WhatIamConsideringBuying").value as? String ?? "No WhatIamConsideringBuying"
        print(education, whatIamConsideringBuying)

    })
}

func loadPeopleWhoLikeMe() {
    let uid = Auth.auth().currentUser!.uid
    let thisUserRef = Database.database().reference().child("people").child(uid)
    let myPeopleRef = thisUserRef.child("peopleWhoLike")
    myPeopleRef.observeSingleEvent(of: .value, with: { snapshot in
        let peopleArray = snapshot.children.allObjects as! [DataSnapshot]
        for person in peopleArray {
            let personUid = person.value as! String
            self.printPersonInfo(uid: personUid)
        }
    })
}

Answer 1

假设您有两个Firebase节点，一个用于存储“人员”，一个用于存储实际用户，那么下面的代码可以执行您想要的操作。

people
   uid_0
      likes: 45
      peopleWhoLike:
         random_0: uid_1
   uid_1
       like: 12
       peopleWhoLike:
          random_0: uid_2
          random_1: uid_3

然后是存储所有用户信息的主要用户节点

users
   uid_0
      email: "bill@mostexcellent.com"
      name: "bill"
   uid_1
      email: "ziggy@stardust.com"
      name: "ziggy"
   uid_2
      email: "leroy@jenkins.com"
      name: "leroy"
   uid_3
      email: "ted@ mostexcellent.com"
      name: "ted"

目的是读取当前用户的“人员”节点并获取喜欢该用户的人员的信息。 假设已登录的用户是uid_1，我们将检索uid_2和uid_3的信息。

func loadPeopleWhoLikeMe() {
    let thisUserRef = self.ref.child("people").child("uid_1")
    let myPeopleRef = thisUserRef.child("peopleWhoLike")
    myPeopleRef.observeSingleEvent(of: .value, with: { snapshot in
        let peopleArray = snapshot.children.allObjects as! [DataSnapshot]
        for person in peopleArray {
            let personUid = person.value as! String
            self.printPersonInfo(withUid: personUid)
        }
    })
}

上面的代码获得了对uid_1的peopleWhoLike子节点的引用，加载了所有子节点，然后遍历每个子节点以获得每个喜欢它们的人的对应uid。 在读取每个文件时，我们会将用户uid传递给另一个函数，以读取电子邮件和姓名，然后将其打印到控制台。 它也可以加载他们的图片或其他任务。

func printPersonInfo(withUid: String) {
    let usersRef = self.ref.child("users")
    let thisUser = usersRef.child(withUid)
    thisUser.observeSingleEvent(of: .value, with: { snapshot in
        let name = snapshot.childSnapshot(forPath: "name").value as? String ?? "No name"
        let email = snapshot.childSnapshot(forPath: "email").value as? String ?? "No email"
        print(name, email)
    })
}

当此代码针对上述结构运行时，输出为

leroy leroy@jenkins.com
ted ted@mostexcellent.com