ios - 在 Swift 中访问函数外部的变量

Question

我想访问此函数外部的“posts”，以便我可以在函数外部调用 tableview.reloaddata() 。每次有键进入 qeoquery 时，下面的代码都会调用 tableview.reloaddata() 。我只想重新加载一次。但是当我尝试 viewDidLoad 时，“posts”数组为空。该怎么办？

在函数外部声明的帖子:

var  posts = [Post]()

功能:

func fetchData(){


        geofireRef = Database.database().reference().child("LOCATION")
        geofire = GeoFire(firebaseRef: geofireRef)
        let geoQuery = geofire?.query(at: myLoc, withRadius: 5.0)

        geoQuery?.observe(.keyEntered, with: { (key: String!, location: CLLocation!) in
            print("KEYKEY: \(key)")
            let dbRef = Database.database().reference().child("posts")
            let query = dbRef.queryOrdered(byChild: "\(key)")
            query.observeSingleEvent(of: .value, with: { (snapshot) in
                if let snapshot = snapshot.children.allObjects as? [DataSnapshot]{
                    for snap in snapshot {
                        if let postDict = snap.value as? Dictionary<String, Any>{
                            let key = snap.key
                            let post = Post.init(postKey: key, postData: postDict)


                            self.posts.append(post)
                        }
                    }
                }
                //self.posts.reverse()
                //self.tableView.reloadData()
                //print("POSTS: \(self.posts)")
            })
        })
    }

Answer 1

您可以在设置 posts 变量后立即调用 tableView.reloadData() (就像您已注释掉的那样)，也可以在帖子上放置 didSet 观察者变量并在设置后重新加载 tableView。如果您选择第二个选项，您将需要重组解析器以仅设置帖子一次，而不是一次附加一个项目。看起来像这样:

var posts = [Post]() {
    didSet {
        self.tableView.reloadData()
    }
}

geoQuery?.observe(.keyEntered, with: { (key: String!, location: CLLocation!) in
        print("KEYKEY: \(key)")
        let dbRef = Database.database().reference().child("posts")
        let query = dbRef.queryOrdered(byChild: "\(key)")
        query.observeSingleEvent(of: .value, with: { (snapshot) in
            if let snapshot = snapshot.children.allObjects as? [DataSnapshot]{
                //Create a variable to hold posts until you've parsed all of them
                var foundPosts = [Post]()
                for snap in snapshot {
                    if let postDict = snap.value as? Dictionary<String, Any>{
                        let key = snap.key
                        let post = Post.init(postKey: key, postData: postDict)
                        foundPosts.append(post)
                    }
                }
                //Set the posts to be all the found posts
                self.posts = foundPosts
            }
        })
    })