Question

我在一个函数中尝试从Firebase检索两组数据时遇到问题。在检索之后，此检索的结果将用于更新进度条（否则为“零”值），因此此进度条＆＃39;功能也包含在Firebase功能中。为了进一步说明，我正在努力获取“用户帖子”和“用户计划”的条目数量。来自Firebase Db： -

该函数的代码如下所示（然后我会告诉您这是什么问题！）： -

func firebaseRetrieve() {

    guard let uid = Auth.auth().currentUser?.uid else {return}

    let planRef = DB_BASE.child("user-plan").child(uid)
    planRef.observeSingleEvent(of: .value, with: { (snapshot) in
        for child in snapshot.children {
            let snap = child as! DataSnapshot
            let key = snap.key
            self.totalPlans.append(key)
            self.planCount = Double(self.totalPlans.count)

            let postRef = DB_BASE.child("user-posts").child(uid)
            postRef.observeSingleEvent(of: .value, with: { (snapshot) in
                for child in snapshot.children {
                    let snaps = child as! DataSnapshot
                    let keys = snaps.key
                    self.totalPosts.append(keys)
                    self.postCount = Double(self.totalPosts.count)

                    self.fraction = self.postCount / self.planCount

                    //THIS IS WHERE I INPUT ANOTHER FUNCTION TO PASS THE VALUE OF 'FRACTION' INTO, THAT THNE DETERMINES THE PROGRESS BAR
                }
            })
        }
    })

问题：用户计划的当前计数＆＃39;是18.用户帖子的当前数量＆＃39;那么分数应该等于0.77（78％）。但是，＆＃39;用户帖子＆＃39;似乎重复18次，所以计数是252（即14 * 18）!!在过去的3天里，我尝试过各种修复方法，但结果总是一样。任何想法都很受欢迎，并会阻止我向妻子发誓......

Answer 1

您可以使用snapshot.childrenCount来获取快照子项的计数，并且需要将计算移动到循环外的分数

结帐此代码

func firebaseRetrieve() 
{

    guard let uid = Auth.auth().currentUser?.uid else {return}

    let planRef = DB_BASE.child("user-plan").child(uid)
    planRef.observeSingleEvent(of: .value, with: 
    { 
        (snapshot) in

        self.planCount = snapshot.childrenCount;
        for child in snapshot.children 
        {
            let snap = child as! DataSnapshot
            let key = snap.key
            self.totalPlans.append(key)
        }


        let postRef = DB_BASE.child("user-posts").child(uid)
        postRef.observeSingleEvent(of: .value, with: 
        { 
            (snapshot) in

            self.postCount = snapshot.childrenCount;
            for child in snapshot.children 
            {
                let snaps = child as! DataSnapshot
                let keys = snaps.key
                self.totalPosts.append(keys)
            }

            self.fraction = self.postCount / self.planCount;
            print("fraction = \(self.fraction)")

        })

    });

}

Swift Firebase - 尝试在函数中检索多组数据以计算条目数

1 个答案: