如何更新 table 视图

Question

我使用了搜索栏。它不会更新 table 视图。

struct ApiResults:Decodable {
    let resultCount: Int
    let results: [Music]
}

struct Music:Decodable {
    let trackName: String?
    let artistName: String?
    let artworkUrl60: String?
}

class ItunesDataViewController: UIViewController, UITableViewDataSource, UITableViewDelegate, UISearchBarDelegate {

    @IBOutlet weak var searchBar: UISearchBar!
    @IBOutlet weak var tableView: UITableView!
    var musicArray:[Music] = []
    var mArray:[Music] = []
    var filteredData:[Music] = []
    var isSearching = false

    override func viewDidLoad() {
        super.viewDidLoad()

        self.tableView.dataSource = self
        self.tableView.delegate = self

        self.searchBar.delegate = self
        searchBar.placeholder = "search"

    }
     func searchBar(_ searchBar: UISearchBar, textDidChange searchText: String)
    {

        print("\n\nsearchText : \(searchText)\n\n")
        Search(searchTerm: "\(searchText)")

        if searchBar.text == nil || searchBar.text == ""
        {
            isSearching = false
            view.endEditing(true)
            self.tableView.reloadData()
        }
        else
        {
            isSearching = true
            filteredData = mArray.filter{[=11=].artistName == searchText}
            self.tableView.reloadData()
        }

    }
    func Search(searchTerm: String)
    {

        guard let url = URL(string: "https://itunes.apple.com/search?term=\(searchTerm)&attribute=actorTerm&attribute=languageTerm&attribute=allArtistTerm&attribute=tvEpisodeTerm&attribute=shortFilmTerm&attribute=directorTerm&attribute=releaseYearTerm&attribute=titleTerm&attribute=featureFilmTerm&attribute=ratingIndex&attribute=keywordsTerm&attribute=descriptionTerm&attribute=authorTerm&attribute=genreIndex&attribute=mixTerm&attribute=allTrackTerm&attribute=artistTerm&attribute=composerTerm&attribute=tvSeasonTerm&attribute=producerTerm&attribute=ratingTerm&attribute=songTerm&attribute=movieArtistTerm&attribute=showTerm&attribute=movieTerm&attribute=albumTerm") else {return}
        URLSession.shared.dataTask(with: url){(data, response, error) in
            guard let data = data else {return}

            do
            {
                let apiressults = try JSONDecoder().decode(ApiResults.self, from: data)

                for item in apiressults.results
                {
                    if let track_Name = item.trackName, let artist_Name = item.artistName, let artwork_Url60 = item.artworkUrl60
                    {
                        let musics = Music(trackName: track_Name, artistName: artist_Name, artworkUrl60: artwork_Url60)
                        self.musicArray.append(musics)
                        print(musics.artistName!,"-", musics.trackName!)
                    }
                }                
                DispatchQueue.main.async
                    {
                        self.tableView.reloadData()
                }
            }
            catch let jsonError
            {
                print("Error:", jsonError)
            }
            }.resume()
    }

    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        if isSearching
        {
            return filteredData.count
        }
        else
        {
            return mArray.count
        }
    }

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "musicCell", for: indexPath) as! ItunesDataTableViewCell

        if isSearching
        {
            cell.lblDesc?.text = filteredData[indexPath.row].artistName
            cell.lblSongDesc?.text = filteredData[indexPath.row].trackName
            let imgString = filteredData[indexPath.row].artworkUrl60!

            let imgUrl:URL = URL(string: imgString)!
            DispatchQueue.global(qos: .userInitiated).async {

                let imageData:NSData = NSData(contentsOf: imgUrl)!

                DispatchQueue.main.async {
                    let image = UIImage(data: imageData as Data)
                    cell.imgArt?.image = image
                }
            }
        }
        else
        {
            cell.lblDesc?.text = mArray[indexPath.row].artistName
            cell.lblSongDesc?.text = mArray[indexPath.row].trackName
            let imgString = mArray[indexPath.row].artworkUrl60!

            let imgUrl:URL = URL(string: imgString)!
            DispatchQueue.global(qos: .userInitiated).async {

                let imageData:NSData = NSData(contentsOf: imgUrl)!

                DispatchQueue.main.async {
                    let image = UIImage(data: imageData as Data)
                    cell.imgArt?.image = image
                }
            }
        }

        return cell
    }
}

Answer 1

请清理您的代码：您有两个不同的数组 mArray 和 musicArray。

您正在 Search 中填充 musicArray，但 mArray 被用作数据源。

为什么要从 Music 项创建新的 Music 项？您可以将代码缩减为

let apiressults = try JSONDecoder().decode(ApiResults.self, from: data)
self.mArray = apiressults.results
DispatchQueue.main.async {
   self.tableView.reloadData()
}

Answer 2

请将 cellForRowAt 委托方法中的代码更改为：

 func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "musicCell", for: indexPath) as! ItunesDataTableViewCell

        let tempArray: [Music] = isSearching ? filteredData : musicArray

        cell.lblDesc?.text = tempArray[indexPath.row].artistName
        cell.lblSongDesc?.text = tempArray[indexPath.row].trackName

        guard let imgString = tempArray[indexPath.row].artworkUrl60,
            let imgUrl = URL(string: imgString) else {
                // Handle properly the fact that there's no image to display
                return cell
        }

        // Review this code as I'm not sure about this double dispatch
        // However, please, no force unwrap optionals (!)
        DispatchQueue.global(qos: .userInitiated).async {
            do {
                let imageData = try Data(contentsOf: imgUrl)
                DispatchQueue.main.async {
                    let image = UIImage(data: imageData)
                    cell.imgArt?.image = image
                }
            } catch let error {
                print("Error with the image URL: ", error)
            }
        }
        return cell
    }

看看你怎么不那样重复你的代码？

此外，您没有使用正确的 music 阵列，或者我们没有所有信息来评估这种 mArray 和 musicArray 的混合有什么问题。

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