ios - UITableView willDisplay 在调用 API 分页时不断调用自身，问题在于异步 API 调用

问题描述

我正在使用 MVVM 并且这个 tableview 委托在 ViewController 问题是因为 API 调用函数使用 ViewModel 对象

func tableView(_ tableView: UITableView, willDisplay cell: UITableViewCell, forRowAt indexPath: IndexPath) {
    if indexPath.row == photosVM.albumData.photos!.photo!.count - 1 {
        if photosVM.albumData.photos!.pages! >= photosVM.albumData.photos!.page! {
            spinner.color = UIColor.FlickrAlbum_theme
            spinner = UIActivityIndicatorView(style: .medium)
            spinner.startAnimating()
            spinner.frame = CGRect(x: CGFloat(0), y: CGFloat(0), width: tableView.bounds.width, height: CGFloat(44))
            tblPhotos.tableFooterView = spinner
            tblPhotos.tableFooterView?.isHidden = false
                //Calling search API with search keywords
                photosVM.getPhotos(pageNumber: photosVM.albumData.photos!.page! + 1, searchText: txtSearch.text!) { [self] (status) in
                    lblDescription.text = txtSearch.text
                    if status == "success" {
                        lblDescription.text = txtSearch.text
                        tblPhotos.reloadData()
                    }
                    else {
                        //showing error message
                        showAlert(message: status)
                    }
                }
            spinner.stopAnimating()
            tblPhotos.tableFooterView = nil
            tblPhotos.tableFooterView?.isHidden = true
        }
   }

这是我的 ViewModel，其中我有一个调用 API 并将数据绑定到视图控制器的功能

func getPhotos(pageNumber: Int = 1, completion: @escaping (String) -> Void) {
    let params = GetPhotosBody()
    params.format = "json"
    params.apiKey = Constants.apiKey
    params.nojsoncallback = 1
    params.page = pageNumber
    params.text = ""
    params.contentType = 1
    ServerManager.getAllPhotos(params: params) { [self] (status, data) in
        if status == "success" {
            if pageNumber == 1 {
                albumData = data
            }
            else {
                 albumData.photos?.page = data?.photos?.page!
                 albumData.photos?.photo?.append(contentsOf: (data!.photos!.photo!))
            }
            //Cache Data
             DataCache.instance.write(object: albumData.toJSON() as NSCoding, forKey: CacheValue.photos)
        }
        if let photos = DataCache.instance.readObject(forKey: CacheValue.photos) {
            albumData = Mapper<FlickrAlbumPhotosResponse>().map(JSONObject: photos)
       }
       else {
           albumData = nil
       }
        completion(status)
    }
}

这是 API 调用管理器，我正在使用 completionblock 来处理异步方法

public static func getAllPhotos(params: GetPhotosBody, completion: @escaping (String ,FlickrAlbumPhotosResponse?) -> Void) {
    //creating URL
    //addingPercentEncoding is used for encoding the url string to support text with spaces
    let url = "\(Constants.baseURL)\(FlickrAlbumEndpoints.getPhotos.rawValue)&format=\(String(describing: params.format!))&nojsoncallback=\(String(describing: params.nojsoncallback!))&api_key=\(String(describing: params.apiKey!))&page=\(String(describing: params.page!))".addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed)!
    //creating request
    var request = URLRequest(url: URL(string: url)!)
    request.httpMethod = HTTPMethod.get.rawValue
    request.setValue("application/json", forHTTPHeaderField: "Content-Type")
    //Making request to the server to call the API
    Alamofire.request(request).responseObject { (response: DataResponse<FlickrAlbumPhotosResponse>) in
        //Check the response of the API
        switch response.result {
            case .success:
                let data = response.result.value
                completion("success",data)
            case .failure(let error):
                completion(error.localizedDescription, nil)
        }
    }
}

每当我关闭互联网时，它都会一次又一次地显示错误消息，因为它一直在调用将显示委托。如果我以错误的方式使用 MVVM，请告诉我并提出您的建议。谢谢

标签： iosswiftuitableviewmvvmdelegates

ios - UITableView willDisplay 在调用 API 分页时不断调用自身，问题在于异步 API 调用

问题描述

解决方案

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