为什么reloadData（）不会刷新视图？

Question

@IBAction func btnDeleteCell(_ sender: UIButton) {
    let UC = UserControllers()

    UC.deleteSocialPlatform(indexRow)

    DispatchQueue.main.async {
        self.parentCollectionView!.reloadData()
    }

    print(indexRow)
}

btnDeleteCell函数在我的collectionviewcell类内部，而在创建单元格时设置了parentCollectionView：

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

    //if is first element of array
    if indexPath.row == 0
    {
        cell = cvSocialPlatform.dequeueReusableCell(withReuseIdentifier: "DefaultCell", for: indexPath) as! SocialPlatformCollectionViewCell

        cell.setupCommon("socialmedialinkgrey", "defaultCell")
        cell.setupbtnInfoText("Add new link")
        cell.parentCollectionView = self.cvSocialPlatform
    }
    else
    {
        cell = cvSocialPlatform.dequeueReusableCell(withReuseIdentifier: "AddedCell", for: indexPath) as! SocialPlatformCollectionViewCell

        cell.setupCommon("socialmedialink", "addedCell")
        cell.setupInfoTextStr(userSocialPlatform[indexPath.row])
        cell.setupIndex(indexPath.row)
        cell.parentCollectionView = self.cvSocialPlatform
    }

    return cell
}

[只要用户单击特定单元格上的删除按钮，就会删除相应的文本数组，并且在firebase上执行删除过程，但是以某种方式，集合视图不会在视图控制器中刷新。我在这里做错了吗？

删除UserControllers中的功能：

func deleteSocialPlatform(_ indexRow: Int)
{
    let userRef = dbManager.databaseRef.child("users").child(dbManager.currentUserID!)

    userRef.observeSingleEvent(of: .value) { (snapshot) in
    let value = snapshot.value as? NSDictionary

    var socialplatformArray = value?["socialplatform"] as! Array<String>

    print(socialplatformArray)

    socialplatformArray.remove(at: indexRow)
    let newValue = ["socialplatform": socialplatformArray]
    userRef.updateChildValues(newValue)    
}

Answer 1

这就是您的删除功能的外观

func deleteSocialPlatform(_ indexRow: Int)
{
    let userRef = dbManager.databaseRef.child("users").child(dbManager.currentUserID!)

    userRef.observeSingleEvent(of: .value) { (snapshot) in
    let value = snapshot.value as? NSDictionary

    var socialplatformArray = value?["socialplatform"] as! Array<String>

    print(socialplatformArray)

    socialplatformArray.remove(at: indexRow)
    let newValue = ["socialplatform": socialplatformArray]
    userRef.updateChildValues(newValue)
    userSocialPlatform = socialplatformArray
}

Answer 2

 func deleteSocialPlatform(_ indexRow: Int, completion:@escaping(Array<String>) -> ())
    {
        let userRef = dbManager.databaseRef.child("users").child(dbManager.currentUserID!)

        userRef.observeSingleEvent(of: .value) { (snapshot) in
        let value = snapshot.value as? NSDictionary

        var socialplatformArray = value?["socialplatform"] as! Array<String>

        print(socialplatformArray)

        socialplatformArray.remove(at: indexRow)
        let newValue = ["socialplatform": socialplatformArray]
        userRef.updateChildValues(newValue)
        completion(socialplatformArray)

        }

    }

 @IBAction func btnDeleteCell(_ sender: UIButton) {


        let UC = UserControllers()
        let parentViewController = PatientPersonalInfoViewController()

        UC.deleteSocialPlatform(indexRow)
        {
            (socialplatformArray) in

            parentViewController.userSocialPlatform = socialplatformArray

        }

        DispatchQueue.main.async {
            self.parentCollectionView!.reloadData()
        }

        print(indexRow)


    }