ios - 从单元格中的按钮重新加载 Collection View Controller

Question

我在用户好友请求单元格中有一个按钮，当我拒绝它时，它会从数据库中删除他们待处理的好友请求，它会很好地从数据库中删除信息，但我无法访问 UICollectionViewController 该单元格所属，从数据库中重新获取待处理的请求？因此它会从数据库中获取 friend 的请求，而我刚刚拒绝的请求不会在那里，现在我必须离开屏幕再回来才能让它消失吗？

是否无法从 UICollectionView 内的单元格按钮调用 UICollectionView 的函数？

protocol friendsRequestControllerDelegate {

    func fetch()
    }

    class FriendsRequestsCell: UICollectionViewCell, CLLocationManagerDelegate  {

    var delegate: friendsRequestControllerDelegate?

    lazy var declineButton: UIButton = {
        let b = UIButton(type: .system)
        b.backgroundColor = UIColor.black
        b.setTitle("Decline", for: .normal)
        b.setTitleColor(UIColor.white, for: .normal)
        b.addTarget(self, action: #selector(declineFriendRequest), for: .touchUpInside)
        b.layer.cornerRadius = 3
        b.titleLabel?.font = UIFont.boldSystemFont(ofSize: 16)

        return b
    }()

    func declineFriendRequest(){
        print("not yet set")
        guard let userAtRow = user?.uid else { return }

        guard let uid = Auth.auth().currentUser?.uid else { return }            

        let db = Firestore.firestore()

        db.collection("Users").document(uid).collection("Pending Requests").document(userAtRow).delete() { err in
            if let err = err {
                print("Error removing document: \(err)")
            } else {
                print("Document successfully removed!")
                self.frc.collectionView?.reloadData()
            }
        }

      delegate?.fetch()

      }    


    class FriendsRequestsController: UICollectionViewController, UICollectionViewDelegateFlowLayout,friendsRequestControllerDelegate {

    func fetch(){
        firestoreFetchFriendsRequestsUserIds()
        viewWillAppear(true)
    }

    //collectionView?.reloadData()

     func firestoreFetchFriendsRequestsUserIds() {

        guard let uid = Auth.auth().currentUser?.uid else { return }

        let db = Firestore.firestore()

        db.collection("Users").document(uid).collection("Pending Requests").getDocuments() { (querySnapshot, err) in
            if let err = err {
                print("Error getting documents: \(err)")
            } else {
                for document in querySnapshot!.documents {   

                    let d = document.data()

                    d.forEach({ (key: String, value: Any) in

                        print("this is the key",key)

                        Database.firestorefetchUserWithUID(uid: key, completion: { (user) in

                            self.users.append(user)

                            self.collectionView?.reloadData()
                        }    
                        )}   
                    )}   
            }
        }
    }

Answer 1

您的集合单元格中有一些控制元素(让它成为一个按钮)。当您激活它(例如按下按钮)时，一些进程开始，当它完成时， Collection View 必须更新。

如果这是您面临的情况(即我对您的理解是正确的)，我会执行以下操作:

1. 为您的细胞制定协议(protocol):

   /// Used by cells to pass commands to their collection view
   protocol CustomCollectionViewCellDelegate: class {
       /// Requests the delegate to update data
       func reloadData()
   }
   

2. 修改您的自定义单元类以使用该协议(protocol)

   class CustomCollectionViewCell: CollectionViewCell {
   
       // Some your stuff
   
       weak var delegate: CustomCollectionViewCellDelegate?
   
       @IBAction func buttonPressed(_ sender: UIButton) {
           yourAsyncProcess() {
               self.delegate?.reloadData()
           }
       }
   }
   

3. 通过您的 Collection View Controller 采用协议(protocol)并添加以下方法:

   func reloadData() {
       DispatchQueue.main.async {
           self.collectionView.reloadData()
       }
   }
   

4. 更新单元格时设置单元格delegate属性

   override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell
   {
       let cell: CustomCollectionViewCell = collectionView.dequeueReusableCell(withReuseIdentifier: "YourCustomCollectionViewCellReuseIdentifier", for: indexPath) as! CustomCollectionViewCell
   
       // Your custom cell setup setup
   
       cell.delegate = self
       return cell
   }