Question

我想将数据从FeedCollectionViewCell传递到另一个ChatViewController。

内部供稿视图控制器

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell{
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellIdentifier, for: indexPath) as! FeedCollectionViewCell
cell.postTextView.text = posts.reversed()[indexPath.row].caption
cell.postImageView.image = UIImage(named: "photoplaceholder.jpg")
cell.priceTextView.text = posts.reversed()[indexPath.row].price
cell.categoryTextView.text = posts.reversed()[indexPath.row].category
cell.usernameLabel.text = posts.reversed()[indexPath.row].username
cell.buttonEvents = {
    let storyboard = UIStoryboard(name: "Main" , bundle: nil)
    let chatViewController =
        storyboard.instantiateViewController(withIdentifier: "chat")
    self.present(chatViewController, animated: true,completion: nil)
    var receiverIDNumber = cell.usernameLabel.text
}

//我想将receiverIDNumber传递给ChatViewController

ChatViewController内部：

    func sendDataToDatabase(message: String){
    let ref = Database.database().reference()
    let senderIDNumber = Auth.auth().currentUser?.uid
    **//I want receiverIDNumber to be the data that is passed from  FeedViewController**
    let receiverIDNumber = "21"
    let postsReference = ref.child("chats")
    let newPostId = postsReference.childByAutoId().key
    let newPostReference = postsReference.child(newPostId)
    newPostReference.setValue(["message" : messageText.text!, "senderID" : senderIDNumber, "receiverID" : receiverIDNumber], withCompletionBlock: {
        (error, ref) in
        if error != nil {
            return
        }
    })
}

我正在尝试从FeedCollectionViewCell获取receiverIDNumber（将收到该消息的用户）

对于MainViewController中的cell.buttonEvents，它是打开ChatViewController。

Main的模型如下所示：

class Post{
var caption: String
var photoUrl: String
var price: String
var category: String
var username: String
var pic: String
init(captionText: String, photoUrlString: String, priceText: String, categoryText: String, usernameLabel: String, profileImageURL: String){
    caption = captionText
    photoUrl = photoUrlString
    price = priceText
    category = categoryText
    username = usernameLabel
    pic = profileImageURL
}

有关例如在电池，还有就是userprofileimage旁边有一个按钮，人们可以点击与users.Upon聊一下按钮，它会引导他们到ChatViewController.In ChatViewController，我用不同的模式：

class Chat {
var message: String
var senderID: String
var receiverID: String

init(messageTextString: String, senderIDNumber: String, receiverIDNumber: String){
    message = messageTextString
    senderID = senderIDNumber
    receiverID = receiverIDNumber
}

由于receiverIDNumber（receiverUsername）来自ChatCollectionView，我发现难以将其与Main中的用户名进行协调。

Answer 1

首先，将变量添加到ChatViewController类：

class ChatViewController: UIViewController {
    var username: String = ""

    override func viewDidLoad() {
        super.viewDidLoad()

        // Check if userID has been given a value
        if !username.isEmpty {
            // Do stuff here with username
        }
    }
}

然后，您可以在实例化视图控制器后为其分配值。我已将其放在didSelectRow方法中，因此在选择单元格时将出现新的视图控制器。您仍然需要使用cellForItemAt方法制作每个单元格。

override func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: IndexPath) {
    let storyboard = UIStoryboard(name: "Main" , bundle: nil)
    let chatViewController = storyboard.instantiateViewController(withIdentifier: "chat")
    // Here is the important bit
    chatViewController.username = posts.reversed()[indexPath.row].username
    // Present view controller
    self.present(chatViewController, animated: true,completion: nil)
}

一些注意事项：

请勿在{{1}}方法中执行任何操作，查看控制器演示文稿等。每次重绘集合视图时，系统都会为每个项目调用它，因此这将是混乱的。设置每个单元格的外观仅。
制作一个新的反向帖子数组，而不是每次需要时将其翻转：cellForItemAt
我不确定你let reversedPosts = posts.reversed()做了什么。这是按下按钮时调用的闭包吗？这就是我选择单元格时选择呈现新视图控制器的原因。
您也可以使用自定义故事板segue执行此操作，并使用以下方法：buttonEvents显示新视图控制器，并performSegue在数据显示之前将数据发送到新视图控制器。这将取代prepareForSegue等。

在不同的CollectionViewCell

1 个答案: