Question

我对更多页面有数据响应，目前正在加载第1页，仅包含20条记录。

当我呼叫Api时，我给出的第1页如下：

 func getMovies()
    {
        API.getNewMovies(page: 1, completion: {movies in
            self.nowPlayingMovies = movies
            self.tableView.reloadData()
        })
    }

但是我想使第No页变成动态的，并根据页码加载更多数据。

我知道如何检测何时到达最后一行数据。但是到达后，我想增加页面编号并加载下一页的更多数据以及现有数据。

我尝试如下所示。.但我知道这是错误的，无法完全正常工作。

func tableView(_ tableView: UITableView, willDisplay cell: UITableViewCell, forRowAt indexPath: IndexPath) {
        // Check if the last row number is the same as the last current data element
        if indexPath.row == self.nowPlayingMovies.count - 1 {
            var pageNum:Int = 1
            pageNum += 1
            print(pageNum)
           // self.loadMore()
        }
    }

 func loadMore()
    {
      print("lastItem Reached")
         // let lastItem = nowPlayingMovies.last!
        //  print("lastItem \(lastItem)")
        // What Should I write here to load more data along with current data 
    }

我的数据模型

import Foundation

struct APIResults: Decodable {
    let page: Int
    let numResults: Int
    let numPages: Int
    let movies: [Movie]

    private enum CodingKeys: String, CodingKey {
        case page, numResults = "total_results", numPages = "total_pages", movies  = "results"
    }
}

struct Movie: Decodable  {
    let id:Int!
    let posterPath: String
    var videoPath: String?
    let backdrop: String
    let title: String
    var releaseDate: String
    var rating: Double
    let overview: String

    private enum CodingKeys: String, CodingKey {
        case id, posterPath = "poster_path", videoPath, backdrop = "backdrop_path", title, releaseDate = "release_date", rating = "vote_average", overview
    }
}

我正在使用数据模型。请给我解释一些清晰的代码段。

如果您想解释更多代码，请告诉我。我将发布所需的代码。谢谢。

Answer 1

将pageNumber作为参数传递，并将影片附加到数据源。

var lastPageRetrieved: Int
var nowPlayingMovies: [Movie] = []
var atTheEnd: Bool = false

func tableView(_ tableView: UITableView, willDisplay cell: UITableViewCell, forRowAt indexPath: IndexPath) {
    // Check if the last row number is the same as the last current data element
    if indexPath.row == self.nowPlayingMovies.count - 1 {
        // Last item reach, load the next page if we're not at the end
        if !atTheEnd {
            self.loadMore()
        }
    }
}

func loadMore() {
    // Get the next page number
    var nextPage: Int = 1
    if lastPageRetrieved > 0 {
        nextPage += lastPageRetrieved
    }

    // Call the API with the right page number
    getMovies(page: nextPage)
}

func getMovies(page: Int) {
    API.getNewMovies(page: page, completion: {movies in

        guard let movies = movies else {
            // The movies were not loaded, are we at the end?  You can make this even
            //   smarter by checking the number of records in the page and if the records
            //   are less than the max page size, we'll know this is the last page
            self.atTheEnd = true
            return
        }

        // Append the new movies to the data source
        self.nowPlayingMovies += movies

        // Record the last page you retrieved
        self.lastPageRetrieved = page

        // Reload your tableView with the new movies
        self.tableView.reloadData()
    })
}

您需要存储上一次检索的页面，并在获取页面数据后进行设置。另外，请考虑在API无法返回或到达最后一页时进行错误处理。

更新：我对代码进行了编辑，使其更加健壮。

Answer 2

使用方法如下

    func loadMore()
        {
          print("lastItem Reached")
          let startingPageIndex = self.nowPlayingMovies.count + 1 // get the index
          getMoview(startingPageIndex: startingPageIndex) // call load movies api
        }

    func getMovies(startingPageIndex: Int) {
            API.getNewMovies(page: startingPageIndex, completion: {movies in
            if self.nowPlayingMovies.count > 0 {
            self.nowPlayingMovies += movies
            } else {
              self.nowPlayingMovies = movies
            }
            self.tableView.reloadData()
            })
        }

找到页面的最后一项时如何从下一页加载更多数据

我的数据模型

2 个答案: