Question

我正在尝试将元素追加到数组但它返回空数组。我要做的是将与用户选择的标签匹配的元素放在一起。为此，首先我创建了模型。

//Model
    import UIKit
    import Firebase

        struct Team {

            var key: String
            var teamName: String
            var league: String
            var lat: Double
            var lng: Double

            init(snapshot: DataSnapshot) {

                self.key = snapshot.key
                self.teamName = (snapshot.value as! NSDictionary)["teamName"] as? String
                self.league = (snapshot.value as! NSDictionary)["league"] as? String ?? ""
                self.lat = (snapshot.value as! NSDictionary)["lat"] as? Double ?? 0
                self.lng = (snapshot.value as! NSDictionary)["lng"] as? Double ?? 0
            }
        }

firebase结构看起来像这样。

{
   "tags": {
       "NewYork": {
             uid1: 1
             uid2: 1
             uid3: 1
       }, 
      "baseball": {
             uid1: 1
       }
    }
}

首先，我获取了与标签匹配的uids。然后根据与之匹配的uid检索团队的信息。如果同样的uid像上面的uid1一样进来，我想要Xcode打印一些东西。要做到这一点，我这样实现（有更好的方法吗？）但它从未被执行过，因为results.count总是0，即使在追加后也是如此。然而，在追加方法（我在这里评论//）之后，它正确地返回了团队的信息。

func filterTeam(filterTag: FilteredTags) {

            let tag = filterTag.selectedTag.components(separatedBy: "/") //this returns "NewYork" and "baseball"

            var results = [Team]()

            tag.forEach { (key) in

                ref.child("tags").child(key).observe(.value, with: { (snapshot) in
                    guard let dictionary = snapshot.value as? [String:Any] else { return }
                    dictionary.forEach({ (uid,_) in

            if results.count == 0 {
                ref.child("teams").child(uid).observe(.value, with: { (snapshots) in
                    let team = Team(snapshot: snapshots)
                    results.append(team)
             //here         
                    print(results)
                }, withCancel: nil)
            } else {
                for result in results {
                    if result.key == uid {
                        print("same uid!!")
                    } else {
                        ref.child("teams").child(uid).observe(.value, with: { (snapshots) in
                            let team = Team(snapshot: snapshots)
                            results.append(team)
                        }, withCancel: nil)
                    }
                }
            }
     })
    }, withCancel: nil)
   }
 }//func

如何正确追加并实现我想做的事情。提前谢谢！

Firebase数组在Swift循环后变为零

0 个答案: