SwiftUI Date formatting

Question

i take this from Github: https://github.com/emilioschepis/techfeed When i start the app, i getting a issue in the console: Could not convert "Wed, 03 Aug 2011 09:44:00 +0200" to Date. and i have a black screen.

I ´m on the latest xCode version and update the Code. thanks for Answers....

Parser:

import Foundation

class ReleasesParser: NSObject {
typealias CompletionResult = ([Release]) -> Void

private static var formatter: DateFormatter = {
    let formatter = DateFormatter()
    formatter.dateFormat = "E, dd MMM yyyy HH:mm:ss z"
    return formatter
}()

private var releases = [Release]()
private var currentElement = ""
private var currentGuid = ""
private var currentTitle = ""
private var currentDescription = ""
private var currentPubDate = ""
private var completion: CompletionResult?

func parse(data: Data, completion: @escaping CompletionResult) {
    self.completion = completion
    
    if data.isEmpty {
        completion([])
        return
    }
    
    let parser = XMLParser(data: data)
    parser.delegate = self
    parser.parse()
}
}

extension ReleasesParser: XMLParserDelegate {
func parserDidStartDocument(_ parser: XMLParser) {
    releases.removeAll(keepingCapacity: true)
}

func parser(_ parser: XMLParser, didStartElement elementName: String, namespaceURI: String?, qualifiedName qName: String?, attributes attributeDict: [String : String] = [:]) {
    currentElement = elementName
    
    // If we are about to start a new item clear the fields
    if currentElement == "item" {
        currentGuid = ""
        currentTitle = ""
        currentDescription = ""
        currentPubDate = ""
    }
}

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

func parser(_ parser: XMLParser, didEndElement elementName: String, namespaceURI: String?, qualifiedName qName: String?) {
    // If we are about to end an item add it to the list
    if elementName == "item" {
        guard let date = Self.formatter.date(from: currentPubDate) else {
            print("Could not convert \"\(currentPubDate)\" to Date.")
            return
        }
        
        let release = Release(id: currentGuid,
                                  title: currentTitle,
                                  description: currentDescription,
                                  date: date)
        
        releases.append(release)
    }
}

func parserDidEndDocument(_ parser: XMLParser) {
    completion?(releases)
}}

ListViewRow:

import SwiftUI


struct ReleaseRow : View {
var release: Release

private var formatter: DateFormatter = {
    let formatter = DateFormatter()
    formatter.dateFormat = "E, dd MMM yyyy"
    return formatter
}()

init(_ release: Release) {
    self.release = release
}

var body: some View {
    VStack(alignment: .leading) {
        Text(release.title)
            .font(.headline)
        Text("\(release.date, formatter: formatter)")
            .font(.subheadline)
            .foregroundColor(.gray)
    }
    .frame(height: 44.0)
}}

Answer 1

There is a much simpler way to display date/time in

• iOS 15(format parameter)
• iOS 14(formatter parameter)

See example below :

struct TestFormat: View {
    let releaseDate = Date()
    
    static let stackDateFormat: DateFormatter = {
        let formatter = DateFormatter()
        formatter.dateFormat = "E, dd MMM yyyy HH:mm:ss z"
        return formatter
    }()
    
    var body: some View {
        VStack {
           //iOS 15
         Text(releaseDate, format: Date.FormatStyle().year().month().day().weekday().hour().minute().second().timeZone())
            
           //iOS 14 and latter. 
         Text("\(releaseDate, formatter: Self.stackDateFormat)")
        }
    }
}

When supplying the formatter to Test, the on screen label is automatically updated when region settings change. That doesn't happen if converting the date to a string manually like would be done in UIKit.

Answer 2

Your dateFormat in ListViewRow is E, dd MMM yyyy, whereas your date is in format E, dd MMM yyyy HH:mm:ss z. You must convert your date using this dateFormat.

let formatter = DateFormatter()
formatter.dateFormat = "E, dd MMM yyyy HH:mm:ss z"
var date = formatter.date(from: "Wed, 03 Aug 2011 09:44:00 +0200")

You can then use the date object to get a string in your desired format.