swift - 仅从 firebase 检索喜欢的帖子

Question

我只想从 firebase 数据库中检索我喜欢的帖子。

下面是我的数据。我希望这个喜欢帖子的用户仅在该用户喜欢该帖子时才显示该帖子。

我已经在从 firebase 中检索数据，但它会显示所有帖子，而不仅仅是喜欢的帖子。

下面的代码是我正在使用的代码，它的工作原理是，如果我点击喜欢它会显示数据，如果我不喜欢则不会显示数据，但这是显示所有数据。

        DataService.ds.REF_USER_CURRENT.observeSingleEvent(of: .value, with: { (snapshot) in

            if snapshot.hasChild("favourite") {

                print("true Favourits exist")


    DataService.ds.REF_POSTS.observe(DataEventType.value, with: { (snapshot) in
        self.posts = []

        if let snapshot = snapshot.children.allObjects as? [DataSnapshot] {
            for snap in snapshot {
                print("SNAP: \(snap)")
                if let postDict = snap.value as? Dictionary<String, AnyObject> {
                    let key = snap.key
                    let post = Post(postKey: key, postData: postDict)
                    self.posts.append(post)
                }
            }
        }
        self.tableView.reloadData()

        })
            }else {
                print("Tony: Couldnt get the data")
            }

    })
}

从这里用 VLADS ANSWER 编辑>>>>>>>

DataService.ds.REF_USER_CURRENT.observeSingleEvent(of: .value, with: { (snapshot) in

        if snapshot.hasChild("favourite") {


    let refToUser = DataService.ds.REF_USER_CURRENT // <- your userId
    refToUser.child("favourite").observeSingleEvent(of: .value, with: { snapshot in
        let value = snapshot.value as? NSDictionary
        let postsIds = value?.allKeys as! [String]

        for postId in postsIds {
            let refToPost = Database.database().reference(withPath: "posts/" + postId)
            refToPost.observeSingleEvent(of: .value, with: { snapshot in
                if snapshot.exists() {
                self.notAddedLabel.isHidden = true
                print("true Favourits exist")


//      refToPost.observe(DataEventType.value, with: { (snapshot) in
        self.posts = []

        if let snapshot = snapshot.children.allObjects as? [DataSnapshot] {
            for snap in snapshot {
                print("SNAP: \(snap)")
                if let postDict = snap.value as? Dictionary<String, AnyObject> {
                    let key = snap.key
                    let post = Post(postKey: key, postData: postDict)
                    self.posts.append(post)
                }
            }
        }
        self.tableView.reloadData()

//          })
            }else {
                self.notAddedLabel.isHidden = false
                print("Tony: Couldn't get the data")
                }
            })
        }
      })
         }else {
            print("Tony: No Favs added, couldn't get the data")
    }
})
}

Answer 1

第一步: 转到收藏夹 节点并获取所有帖子 ID:

let refToUser = FIRDatabase.database().reference(withPath: "Users").child(userId) // <- your userId
refToUser.child("favourite").observeSingleEvent(of: .value, with: { snapshot in
        if let value = snapshot.value as? NSDictionary
        let postsIds = value.allKeys as! [String]

        // Second step: fetch every post
        for postId in postsIds {
            let refToPost = FIRDatabase.database().reference(withPath: "posts/" + postId)
            refToPost.observeSingleEvent(of: .value, with: { snapshot in
                 if snapshot.exists() {
                     // do whatever you want
                     // snapshot now is your post data
                 } else {
                     print("error")
                 }
            })
        }

因此，您的主要问题是您引用的是所有帖子，而不是特定帖子。

希望你明白了。