如何在我的 iOS RSS 应用程序中显示我解析的 XML 中的图像？

Question

I have an iOS app in Swift that parses XML from an RSS feed from my website.

I want to be able to display the posts' image and also displaying the relevant content (as at the moment it just displays XML code).

Here is the code to the Parser and the cells it controls:

Parser:

import Foundation

struct RSSItem {
    var title: String
    var description: String
    var pubDate: String
}

// download xml from a server
// parse xml to foundation objects
// call back

class FeedParser: NSObject, XMLParserDelegate
{
    private var rssItems: [RSSItem] = []
    private var currentElement = ""

    private var currentTitle: String = "" {
        didSet {
            currentTitle = currentTitle.trimmingCharacters(in: CharacterSet.whitespacesAndNewlines)
        }
    }
    private var currentDescription: String = "" {
        didSet {
            currentDescription = currentDescription.trimmingCharacters(in: CharacterSet.whitespacesAndNewlines)
        }
    }
    private var currentPubDate: String = "" {
        didSet {
            currentPubDate = currentPubDate.trimmingCharacters(in: CharacterSet.whitespacesAndNewlines)
        }
    }
    private var parserCompletionHandler: (([RSSItem]) -> Void)?

    func parseFeed(url: String, completionHandler: (([RSSItem]) -> Void)?)
    {
        self.parserCompletionHandler = completionHandler

        let request = URLRequest(url: URL(string: url)!)
        let urlSession = URLSession.shared
        let task = urlSession.dataTask(with: request) { (data, response, error) in
            guard let data = data else {
                if let error = error {
                    print(error.localizedDescription)
                }

                return
            }

            /// parse our xml data
            let parser = XMLParser(data: data)
            parser.delegate = self
            parser.parse()
        }

        task.resume()
    }

    // MARK: - XML Parser Delegate

    func parser(_ parser: XMLParser, didStartElement elementName: String, namespaceURI: String?, qualifiedName qName: String?, attributes attributeDict: [String : String] = [:])
    {
        currentElement = elementName
        if currentElement == "item" {
            currentTitle = ""
            currentDescription = ""
            currentPubDate = ""
        }
    }

    func parser(_ parser: XMLParser, foundCharacters string: String)
    {
        switch currentElement {
        case "title": currentTitle += string
        case "description" : currentDescription += string
        case "pubDate" : currentPubDate += string
        default: break
        }
    }

    func parser(_ parser: XMLParser, didEndElement elementName: String, namespaceURI: String?, qualifiedName qName: String?)
    {
        if elementName == "item" {
            let rssItem = RSSItem(title: currentTitle, description: currentDescription, pubDate: currentPubDate)
            self.rssItems.append(rssItem)
        }
    }

    func parserDidEndDocument(_ parser: XMLParser) {
        parserCompletionHandler?(rssItems)
    }

    func parser(_ parser: XMLParser, parseErrorOccurred parseError: Error)
    {
        print(parseError.localizedDescription)
    }

}

Cell View Controller:

import UIKit

class NewsTableViewController: UITableViewController
{
    private var rssItems: [RSSItem]?
    private var cellStates: [CellState]?

    override func viewDidLoad() {
        super.viewDidLoad()

        tableView.estimatedRowHeight = 155.0
        tableView.rowHeight = UITableView.automaticDimension

        fetchData()
    }

    private func fetchData()
    {
        let feedParser = FeedParser()
        feedParser.parseFeed(url: "https://appleosophy.com/feed") { (rssItems) in
            self.rssItems = rssItems
            self.cellStates = Array(repeating: .collapsed, count: rssItems.count)

            OperationQueue.main.addOperation {
                self.tableView.reloadSections(IndexSet(integer: 0), with: .left)
            }
        }
    }


    // MARK: - Table view data source

    override func numberOfSections(in tableView: UITableView) -> Int {
        // Return the number of sections
        return 1
    }

    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int
    {
        guard let rssItems = rssItems else {
            return 0
        }

        // rssItems
        return rssItems.count
    }

    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell
    {
        let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath) as! NewsTableViewCell
        if let item = rssItems?[indexPath.item] {
            cell.item = item
            cell.selectionStyle = .none

            if let cellStates = cellStates {
                cell.descriptionLabel.numberOfLines = (cellStates[indexPath.row] == .expanded) ? 0 : 4
            }
        }

        return cell
    }

    override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath)
    {
        tableView.deselectRow(at: indexPath, animated: true)
        let cell = tableView.cellForRow(at: indexPath) as! NewsTableViewCell

        tableView.beginUpdates()
        cell.descriptionLabel.numberOfLines = (cell.descriptionLabel.numberOfLines == 0) ? 3 : 0

        cellStates?[indexPath.row] = (cell.descriptionLabel.numberOfLines == 0) ? .expanded : .collapsed

        tableView.endUpdates()
    }

}

My objective is to have a fully native RSS feed into my app that can display my articles with images and the text attributed to the article.

Answer 1

This answer is quite late, but I'm working on a similar project. I am using SwiftUI and managed to load the remote URLs. Hopefully my solution will be helpful to you:

First you load the image

import Combine
import Foundation
class ImageLoader: ObservableObject { 
    var dataPublisher = PassthroughSubject<Data, Never>() 
    var data = Data() { 
        didSet { 
            dataPublisher.send(data) 
        } 
     }
init(urlString:String) { 
        guard let url = URL(string: urlString) else { return } 
        let task = URLSession.shared.dataTask(with: url) { data, response, error in 
        guard let data = data else { return }         
        DispatchQueue.main.async { 
           self.data = data 
        } 
    } 
    task.resume() 
  }
}

Then you create an imageView:

import Combine
import SwiftUI
struct ImageView: View {
    @ObservedObject var imageLoader:ImageLoader
    @State var image:UIImage = UIImage()
init(withURL url:String) {
        imageLoader = ImageLoader(urlString:url)
    }
var body: some View {
    VStack { 
        Image(uiImage: image)
            .resizable()
            .aspectRatio(contentMode: .fit)
            .frame(width:100, height:100)
    }.onReceive(imageLoader.dataPublisher) { data in
        self.image = UIImage(data: data) ?? UIImage()
    }
  }
}
struct ImageView_Previews: PreviewProvider {
    static var previews: some View {
        ImageView(withURL: "")
    }
}

Then you can use your ImageView to see the image: ImageView(withURL: data.imageURL)