使用firebase

Question

我的一个ViewControllers中有以下代码。我想在tableview中显示评论。写作和阅读有效，但它们根本不会出现在我的桌面视图中。

问题在于它首先显示视图并在之后加载数据。我也不能调用tableview函数。任何帮助都会很棒！

import UIKit
import FirebaseDatabase

class SinglePostViewController: UIViewController, UITableViewDelegate, 
UITableViewDataSource {

@IBOutlet weak var commentTextfield: UITextField!


var commentList:[Comment] = CommentData().loadFromDatabase(postID: "")

@IBOutlet weak var tableView: UITableView!


@IBAction func commentButton(_ sender: Any)
{

    // saving comment to database
    if commentTextfield.text != ""
    {
        let com : Comment = Comment()
        com.setContent(content: commentTextfield.text!)
        CommentData().saveToDatabase(comment: com)
    }
}


// setting up tableview

func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int
{
    return commentList.count

}

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell
{
    print("check tableview")
    let cell = UITableViewCell(style: .default, reuseIdentifier: "cell")
    cell.textLabel?.text = commentList[indexPath.row].getContent()
    return cell
}

func refresh(){
    commentList = CommentData().loadFromDatabase(postID: "")
    self.tableView.reloadData()
}


override func viewDidLoad() {
    print("check viewdidload")
    super.viewDidLoad()
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}


}

CommentData的代码：

 import UIKit
 import Firebase
 import AVFoundation

class CommentData: NSObject {

var databaseReference : DatabaseReference{
    return Database.database().reference()
}

var databaseHandle : DatabaseHandle = 0

func saveToDatabase(comment : Comment){
    do{

        self.databaseReference.child("Comment").childByAutoId().setValue(["userID": comment.getUserID(), "postID" : comment.getPostID(), "content" : comment.getContent(),"LikeFlagCounter" : comment.getLikeFlagCounter()])
    }


}


func loadFromDatabase(postID : String) -> [Comment]{
    var comments : [Comment] = []

    databaseHandle = databaseReference.child("Comment").observe(.childAdded, with: { (snapshot) in
        let comment = Comment()
        if let dictionary = snapshot.value as? [String : AnyObject] {


            for (key, value) in dictionary{
                if key == "userID"{
                    comment.setUserID(userID: value as! Int)
                }
                else if key == "postID"{
                    comment.setPostID(postID: value as! String)
                }
                else if key == "content"{
                    comment.setContent(content: value as! String)
                }
                else if key == "LikeFlagCounter" {
                    comment.setLikeFlagCounter(likeFlagCounter: value as! Int)
                }
            }

        }
        print(comment.getPostID())
        print(postID)
        if comment.getPostID() == postID
        {
            comments.append(comment)
            print(comments.count)
        }
    })
    print("check!!!!!" + String(comments.count))
    return comments
}

}

Answer 1

您尚未为tableView设置dataSource。试试它应该工作。无需在viewDidload上调用reload

@IBOutlet weak var tableView: UITableView! {
     didSet {
          tableView.dataSource = self
     } 
}