Collection View Cells 不断增加，是当前数组数量的两倍

Question

您好，我正在使用数据模型方法将数据加载到 collectionView 单元格中。数据获取成功，但是当我导航到另一个 viewController 并返回到当前 viewController 时，单元格的增加是当前数组计数的两倍。

我知道我使用的方法并不完美，因为我是 Swift 的新手，我是从 google 那里得到的。处理这个问题的正确方法是什么？

API 通话

func postToGetMyCoach()
    {
        let url = "https://xxxxxxxx.azurewebsites.net/api/myCoach"
        var param : [String : AnyObject] = [:]

        param = ["apiKey": apiKey as AnyObject]
        print(param)
        Alamofire.request(url, method: .post, parameters: param, encoding: URLEncoding()).responseJSON { (response:DataResponse<Any>) in

            if (response.result.value != nil)
            {
               if let value = response.result.value
               {
                let json = JSON(value)
                //  let responseDictionary = json.dictionaryValue as [String: AnyObject]
              //  print("json:\(json)")

                /**** Category Array exctraction *****/
                let categoryArray = json["data"]["categories"].arrayValue
                print("Category Array:\(categoryArray)")

                for var mCategory in categoryArray
                {
                    let title = mCategory["title"].stringValue
                    let imageURL = mCategory["image"].stringValue
                    let id = mCategory["id"].stringValue

                    //Escape image url additional Charectors
                    self.cimageURL = imageURL.replacingOccurrences(of: "\", with: "")
                    print("ESCAPED IMAGE URL\(self.cimageURL)")

                //    let mcCategory = categories(description: description, title: title, id :id, dateOfNews: dateOfNews, imageURL:self.cimageURL)
                    let mcCategory = MCCategories(title: title, id:id, imageURL:self.cimageURL)

                    self.categories.append(mcCategory)

                }
                self.collectionView.reloadData()

               }
            }
            else
            {
                print("No Response!",response)
            }
        }

Collectionview 代表

func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return categories.count
    }

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "MyCoachCCell", for: indexPath)
            as! MyCoachCCell

       // cell.activitiesImg.image = collectionViewImageArray[indexPath.row]
        let mCategories = categories[indexPath.row]
        cell.className.text = mCategories.title
     //   cell.classThumb.image = collectionViewImageArray[indexPath.row]

        // fetching image
        let mcImageURL = mCategories.imageURL
        Alamofire.request(mcImageURL).responseData(completionHandler: { response in
            //   debugPrint(response)
            //   debugPrint(response.result)
            if let image1 = response.result.value {
                self.imagefinal = UIImage(data: image1)!
                cell.classThumb.image = self.imagefinal
                print("IMG", self.imagefinal! )

            }
        })

        return cell
    }

Answer 1

请在追加到数组之前编写代码。

self.categories.removeAll()

在你的函数中，在 for 循环开始之前添加这一行。

func postToGetMyCoach()
    {
        let url = "https://xxxxxxxx.azurewebsites.net/api/myCoach"
        var param : [String : AnyObject] = [:]

        param = ["apiKey": apiKey as AnyObject]
        print(param)
        Alamofire.request(url, method: .post, parameters: param, encoding: URLEncoding()).responseJSON { (response:DataResponse<Any>) in

            if (response.result.value != nil)
            {
               if let value = response.result.value
               {
                let json = JSON(value)
                //  let responseDictionary = json.dictionaryValue as [String: AnyObject]
              //  print("json:\(json)")

                /**** Category Array exctraction *****/
                let categoryArray = json["data"]["categories"].arrayValue
                print("Category Array:\(categoryArray)")

                self.categories.removeAll()
                for var mCategory in categoryArray
                {
                    let title = mCategory["title"].stringValue
                    let imageURL = mCategory["image"].stringValue
                    let id = mCategory["id"].stringValue

                    //Escape image url additional Charectors
                    self.cimageURL = imageURL.replacingOccurrences(of: "\", with: "")
                    print("ESCAPED IMAGE URL\(self.cimageURL)")

                //    let mcCategory = categories(description: description, title: title, id :id, dateOfNews: dateOfNews, imageURL:self.cimageURL)
                    let mcCategory = MCCategories(title: title, id:id, imageURL:self.cimageURL)

                    self.categories.append(mcCategory)

                }
                self.collectionView.reloadData()

               }
            }
            else
            {
                print("No Response!",response)
            }
        }

您已经在 viewWillAppear method.So 中调用了网络服务，每当您从另一个视图控制器返回时，它都会将数据附加到相同的现有 array.So，编写上面的代码将从数组中删除现有数据.

或者您可以做的其他事情是在 viewDidLoad 方法中调用网络服务。

希望对您有所帮助。

Answer 2

用这个替换你的函数。

您需要在追加之前从数组类别中删除所有元素。

func postToGetMyCoach()
{
    let url = "https://xxxxxxxx.azurewebsites.net/api/myCoach"
    var param : [String : AnyObject] = [:]

    param = ["apiKey": apiKey as AnyObject]
    print(param)
    Alamofire.request(url, method: .post, parameters: param, encoding: URLEncoding()).responseJSON { (response:DataResponse<Any>) in

        if (response.result.value != nil)
        {
           if let value = response.result.value
           {
            let json = JSON(value)
            //  let responseDictionary = json.dictionaryValue as [String: AnyObject]
          //  print("json:\(json)")

            /**** Category Array exctraction *****/
            let categoryArray = json["data"]["categories"].arrayValue
            print("Category Array:\(categoryArray)")

            self.categories = []
            for var mCategory in categoryArray
            {
                let title = mCategory["title"].stringValue
                let imageURL = mCategory["image"].stringValue
                let id = mCategory["id"].stringValue

                //Escape image url additional Charectors
                self.cimageURL = imageURL.replacingOccurrences(of: "\", with: "")
                print("ESCAPED IMAGE URL\(self.cimageURL)")

            //    let mcCategory = categories(description: description, title: title, id :id, dateOfNews: dateOfNews, imageURL:self.cimageURL)
                let mcCategory = MCCategories(title: title, id:id, imageURL:self.cimageURL)

                self.categories.append(mcCategory)

            }
            self.collectionView.reloadData()

           }
        }
        else
        {
            print("No Response!",response)
        }
    }

Collection View Cells 不断增加，是当前数组数量的两倍

Collection View Cells are keep increasing as twice of the current array count

json

ios

uicollectionview

uicollectionviewcell

swift