swift - 如何将帖子 ID 传递给评论 VC - Swift

Question

我无法将 postid 发送到 comments vc，以便将其保存在 Firebase 中。

我正在遵循我们正在构建的在线教程 this Firebase 上的架构但是当我将数据发送到 Firebase 时，它​​没有捕获 postId，如 this screenshot 上所示。 。我显然错过了一些东西。如果有人能阐明我的错误可能是什么，我将非常感激。下面我将放置 Comments View Controller 函数，将数据发送到 Firebase。

  @IBAction func sendButtonPressed(_ sender: UIButton) {

    let ref = Database.database().reference()
    let commentsReference = ref.child("comments")
    let newCommentId = commentsReference.childByAutoId().key
    let newCommentReference = commentsReference.child(newCommentId)

    //current user information
    guard let currentUser = Auth.auth().currentUser else {
        return
    }

    let currentUserId = currentUser.uid
    newCommentReference.setValue(["userid": currentUserId, "commentText": commentTextField.text!]) { (error, ref) in

        if error != nil {
            ProgressHUD.showError(error!.localizedDescription)
            return
            }
        let postCommentRef = Database.database().reference().child("post-comments").child(self.postIdNew).child(newCommentId)
        postCommentRef.setValue(true, withCompletionBlock: { (error, ref) in
            if error != nil {
                ProgressHUD.showError(error!.localizedDescription)
                return
            }
        })
        self.empty()
        self.view.endEditing(true)
    }
}

这就是我从主视图 Controller 获取 postId 引用的方式。

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if segue.identifier == "commentSegue" {
        let commentVC = segue.destination as! CommentViewController
        let postId = sender as! String
        commentVC.postIdNew = postId
    }
}

这是我的 Collection View 扩展

extension HomeViewController: UICollectionViewDelegate, UICollectionViewDataSource {

func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {

    if collectionView == self.lostCollectionView {

        return posts.count
    }

    if collectionView == self.foundCollectionView {

        return newPostsFound.count

    }

    if collectionView == self.adoptionCollectionView {

        return postsadoption.count
    }

    else {

        return 0
    }

}

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {

    switch collectionView {

    case lostCollectionView:

        let lostcell: LostCollectionViewCell = collectionView.dequeueReusableCell(withReuseIdentifier: "Lostcell", for: indexPath) as! LostCollectionViewCell

        let post = posts[indexPath.row]
        let user = users[indexPath.row]
        lostcell.post = post
        lostcell.user = user

        //Make TextView Clickable
        lostcell.phoneLostTextView.isEditable = false;
        lostcell.phoneLostTextView.dataDetectorTypes = UIDataDetectorTypes.phoneNumber

        //Make Comments View Clickable
        lostcell.homeVC = self
        return lostcell


    case foundCollectionView:
        let foundcell: FoundCollectionViewCell = collectionView.dequeueReusableCell(withReuseIdentifier: "Foundcell", for: indexPath) as! FoundCollectionViewCell

        let post = newPostsFound[indexPath.row]
        foundcell.post = post

        //Make TextView Clickable
        foundcell.phoneFoundTextView.isEditable = false;
        foundcell.phoneFoundTextView.dataDetectorTypes = UIDataDetectorTypes.phoneNumber
        return foundcell

    case adoptionCollectionView:
        let adoptioncell: AdoptionCollectionViewCell = collectionView.dequeueReusableCell(withReuseIdentifier: "Adopotioncell", for: indexPath) as! AdoptionCollectionViewCell

        let post = postsadoption[indexPath.row]
        adoptioncell.post = post

        //Make TextView Clickable
        adoptioncell.phoneAdoptionTextView.isEditable = false;
        adoptioncell.phoneAdoptionTextView.dataDetectorTypes = UIDataDetectorTypes.phoneNumber
        return adoptioncell

    default:
        return UICollectionViewCell()
    }

    }

func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {


    switch collectionView {

    case lostCollectionView:

        let vc = storyboard?.instantiateViewController(withIdentifier: "lostSelectedViewController") as? LostSelectedViewController
        self.navigationController?.pushViewController(vc!, animated: true)
        vc?.posts = posts[indexPath.row]
        break

    case foundCollectionView:
       let vc = storyboard?.instantiateViewController(withIdentifier: "foundSelectedViewController") as? FoundSelectedViewController
       self.navigationController?.pushViewController(vc!, animated: true)
        vc?.posts = newPostsFound[indexPath.row]
        break

    case adoptionCollectionView:
        let vc = storyboard?.instantiateViewController(withIdentifier: "adoptionSelectedViewController") as? AdoptionSelectedViewController
        self.navigationController?.pushViewController(vc!, animated: true)
        vc?.posts = postsadoption[indexPath.row]
        break

    default:
        break
    }

    func commentsViewPressed() {
        print("Hola")
        performSegue(withIdentifier: "commentSegue", sender: self)

    }
}

}

Answer 1

问题看起来就在这段代码中

let postId = sender as! String
commentVC.postIdNew = postId

Sender 指启动segue的对象，很可能是一个按钮或TableViewCell(请参阅苹果文档:https://developer.apple.com/documentation/uikit/uiviewcontroller/1621490-prepare)

您需要将 sender 替换为! String 包含您尝试设置的 postId 的值。我假设您可以从第一个 View Controller 上的某个地方获取它。