拉动刷新不起作用

Question

我正在使用Alamofire在Swift 3中构建我的应用程序.我将JSON数据放入列表视图中.每次我刷新内容而不是刷新内容时,它只是在列表视图中的列表底部添加更多项目,而不是刷新可见列表.我不知道我做错了什么,到目前为止,我的代码是:

import UIKit
import Alamofire
import SVProgressHUD

struct postinput {
    let mainImage : UIImage!
    let name : String!
    let author : String!
    let summary : String!
    let content : String!


}


class TableViewController: UITableViewController {

    //var activityIndicatorView: UIActivityIndicatorView!

    var postsinput = [postinput]()

    var refresh = UIRefreshControl()

    var mainURL = "https://www.example.com/api"

    typealias JSONstandard = [String : AnyObject]

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        tableView.separatorStyle = UITableViewCellSeparatorStyle.none


        self.tableView.addSubview(refresh)

        //;refresh.attributedTitle = NSAttributedString(string: "Refreshing...", attributes:[NSForegroundColorAttributeName : UIColor.black])
        refresh.backgroundColor = UIColor(red:0.93, green:0.93, blue:0.93, alpha:1.0)
        //refresh.tintColor = UIColor.white

        refresh.addTarget(self, action: #selector(self.refreshData), for: UIControlEvents.valueChanged)
        //refresh.addTarget(self, action: #selector(getter: TableViewController.refresh), for: UIControlEvents.valueChanged)
        refresh.attributedTitle = NSAttributedString(string: "Updated: \(NSDate())")


        //activityIndicatorView = UIActivityIndicatorView(activityIndicatorStyle: UIActivityIndicatorViewStyle.gray)
        //tableView.backgroundView = activityIndicatorView

        callAlamo(url: mainURL)


    }

    func refreshData() {

        Alamofire.request("https://www.example.com/api").responseJSON(completionHandler: {
            response in
            self.parseData(JSONData: response.data!)
            self.tableView.separatorStyle = UITableViewCellSeparatorStyle.singleLine

            DispatchQueue.main.async {
                self.tableView.reloadData()
                self.refresh.endRefreshing()
            }


        })



    }



    func callAlamo(url : String){
        //activityIndicatorView.startAnimating()
        SVProgressHUD.show(withStatus: "Loading...")
        SVProgressHUD.setDefaultStyle(SVProgressHUDStyle.dark)
        SVProgressHUD.setDefaultAnimationType(SVProgressHUDAnimationType.native)
        SVProgressHUD.setDefaultMaskType(SVProgressHUDMaskType.black)
        Alamofire.request(url).responseJSON(completionHandler: {
            response in
            self.parseData(JSONData: response.data!)
            self.tableView.separatorStyle = UITableViewCellSeparatorStyle.singleLine
            //self.activityIndicatorView.stopAnimating()
            SVProgressHUD.dismiss()


        })


    }


    func parseData(JSONData : Data) {
        do {
            var readableJSON = try JSONSerialization.jsonObject(with: JSONData, options: .mutableContainers) as! JSONstandard
            // print(readableJSON)

            if let posts = readableJSON["posts"] as? [JSONstandard] {
                for post in posts {
                    let title = post["title"] as! String

                    let author = post["author"] as! String

                    guard let dic = post["summary"] as? [String: Any], let summary = dic["value"] as? String else {
                        return
                    }
                    let str = summary.replacingOccurrences(of: "<[^>]+>", with: "", options: .regularExpression, range: nil)
                    print(str)

                    guard let dic1 = post["content"] as? [String: Any], let content = dic1["value"] as? String else {
                        return
                    }
                    let str1 = content.replacingOccurrences(of: "<[^>]+>", with: "", options: .regularExpression, range: nil)
                    print(str1)





                    //print(author)

                    if let imageUrl = post["image"] as? String {
                        let mainImageURL = URL(string: imageUrl )
                        let mainImageData = NSData(contentsOf: mainImageURL!)
                        let mainImage = UIImage(data: mainImageData as! Data)

                        postsinput.append(postinput.init(mainImage: mainImage, name: title, author: author, summary: summary, content: content))
                    }
                }
                DispatchQueue.main.async {
                    self.tableView.reloadData()
                }
            }


        }


        catch {
            print(error)
        }


    }


    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return postsinput.count
    }

    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "cell")

        // cell?.textLabel?.text = titles[indexPath.row]

        let mainImageView = cell?.viewWithTag(2) as! UIImageView

        mainImageView.image = postsinput[indexPath.row].mainImage

        mainImageView.layer.cornerRadius = 5.0
        mainImageView.clipsToBounds = true

        //(cell?.viewWithTag(2) as! UIImageView).image = postsinput[indexPath.row].mainImage

        let mainLabel = cell?.viewWithTag(1) as! UILabel

        mainLabel.text = postsinput[indexPath.row].name

        mainLabel.font = UIFont.boldSystemFont(ofSize: 18)

        mainLabel.sizeToFit()

        mainLabel.numberOfLines = 0;

        let autLabel = cell?.viewWithTag(3) as! UILabel

        autLabel.text = postsinput[indexPath.row].author

        autLabel.font = UIFont(name: "Helvetica", size:16)

        autLabel.textColor = UIColor(red: 0.8784, green: 0, blue: 0.1373, alpha: 1.0) /* #e00023 */

        let sumLabel = cell?.viewWithTag(4) as! UILabel

        sumLabel.text = (postsinput[indexPath.row].summary).replacingOccurrences(of: "<[^>]+>", with: "", options: .regularExpression, range: nil)

        sumLabel.font = UIFont(name: "Helvetica", size:16)

        sumLabel.textColor = UIColor(red:0.27, green:0.27, blue:0.27, alpha:1.0)

        //let contentLabel = cell?.viewWithTag(0) as! UILabel

        //contentLabel.text = (postsinput[indexPath.row].content).replacingOccurrences(of: "<[^>]+>", with: "", options: .regularExpression, range: nil)



        //(cell?.viewWithTag(3) as! UILabel).text = postsinput[indexPath.row].author

        return cell!
    }

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        SVProgressHUD.show()
        let indexPath = self.tableView.indexPathForSelectedRow?.row

        let vc = segue.destination as! nextVC


        vc.articleImage = postsinput[indexPath!].mainImage
        vc.articleMainTitle = postsinput[indexPath!].name
        vc.articleContent = postsinput[indexPath!].content
        SVProgressHUD.dismiss()

        let backItem = UIBarButtonItem()
        backItem.title = "Back"
        navigationItem.backBarButtonItem = backItem // This will show in the next view controller being pushed



    }


    override func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {
        if editingStyle == .delete {
            postsinput.remove(at: indexPath.row)
            tableView.deleteRows(at: [indexPath], with: .fade)
        } else if editingStyle == .insert {
            // Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view.
        }
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }


}

Answer 1

你的问题在这里:

postsinput.append(postinput.init(mainImage: mainImage, name: title, author: author, summary: summary, content: content))

您不断将新数据附加到旧数据.如果要在添加新数据之前完全清除旧数据,只需从postsinput阵列中删除所有元素即可.