ios - 如何访问数组中自定义对象的值？

Question

我目前有一个自定义对象

public struct GenreData : Decodable {


  public let id : NSNumber?
  public let name : String


  public init?(json: JSON) {

    guard let name : String = "name" <~~ json
      else {return nil}

    self.id = "id" <~~ json
    self.name = name

  }
}

我有一个自定义对象的数组，并且正在尝试访问该对象的“id”部分，以便我可以将其插入另一个函数:

  var genreDataArray: [GenreData] = []
  var posterStringArray: [String] = []
  var posterImageArray: [UIImage] = []

 GenreData.updateAllData(urlExtension:"list", completionHandler: { results in

      guard let results = results else {
        print("There was an error retrieving info")
        return
      }
      self.genreDataArray = results

      for _ in self.genreDataArray {

      if let movieGenreID = self.genreDataArray[0].id {//This is where the ID is needed to access the posters

        print(movieGenreID)

        //Update posters based on genreID
        GenrePosters.updateGenrePoster(genreID: movieGenreID, urlExtension: "movies", completionHandler: {posters in

          //Must iterate through multiple arrays with many containing the same poster strings
          for poster in posters {

            //Check to see if array already has the current poster string, if it does continue, if not append to array
            if self.posterStringArray.contains(poster){
              continue
            } else {
              self.posterStringArray.append(poster)

              //Use the poster string to download the corresponding poster
              self.networkManager.downloadImage(imageExtension: "\(poster)",
                { (imageData) //imageData = Image data downloaded from web
                  in
                  if let image = UIImage(data: imageData as Data){
                    self.posterImageArray.append(image)

                  }
              })
            }
          }
        })
      }
      }
      DispatchQueue.main.async {
        self.genresTableView.reloadData()
      }
    })

到目前为止，它所做的就是访问 JSON 数据的第一个数组(有 19 个数组)并将第一个数组中的每个字符串附加到 posterStringArray，但我需要它遍历每个数组并仅附加如果海报字符串数组中尚不存在字符串。

Answer 1

我不能百分百确定我理解你的问题，但你不应该替换:

for _ in self.genreDataArray {

  if let movieGenreID = self.genreDataArray[0].id 

与

for item in self.genreDataArray {

  if let movieGenreID = item.id 

更新

要仅添加一项，请尝试在获取图像后添加中断:

          //Use the poster string to download the corresponding poster
          self.networkManager.downloadImage(imageExtension: "\(poster)",
            { (imageData) //imageData = Image data downloaded from web
              in
              if let image = UIImage(data: imageData as Data){
                self.posterImageArray.append(image)

              }
          })

          break