Question 177108 in IOS Swift Question posted in
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Does TableView reload same content when populated through unwind segue in iOS Swift?

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  1. I have 2 structs for the data to be passed to the tableView:

     struct Session {
     let dateModel: Date?
     let timeBegModel: Date?
     let timeEndModel: Date?
     let sessionModel: String?
     let venueModel: String?
     var formattedTimeBeg: String {
         guard let text = timeBegModel else {
             return ""
         }
         return DateFormatter.adjustedTimeFormat.string(from: text)
     }
     var formattedTimeEnd: String {
         guard let text = timeEndModel else {
             return ""
         }
         return DateFormatter.adjustedTimeFormat.string(from: text)
     }
 }

  2. The data is passed from another viewController with unwind segue:

     @IBAction func unwindToMainVC(segue: UIStoryboardSegue) {
     guard let vc = segue.source as? AddSessionVC else { return }
     guard let date = vc.dateDP?.date, let timeBeg = vc.timeBegDP?.date, let timeEnd = vc.timeEndDP?.date, let session = vc.sessionTF.text, let venue = vc.venueTF.text else { return }
 let Session = Session(dateModel: date, timeBegModel: timeBeg, timeEndModel: timeEnd, sessionModel: session, venueModel: venue)
 sessions.append(Session)
 sessions.sort { $0.timeBegModel! < $1.timeEndModel! }
 sortByDate() // I tried to put this func in the viewDidLoad(), but it doesn't work
 tableView.reloadData()
 }

  3. I have a function to set up the date as a tableView section header:

     func sortByDate() {
     let datesInSessions = sessions.reduce(into: Set<Date>()) { result, sessions in
         let dateInSession = Calendar.current.startOfDay(for: sessions.dateModel!)
         result.insert(dateInSession)
     }
     for dateInSession in datesInSessions {
         let dateComp = Calendar.current.dateComponents([.year, .month, .day], from: dateInSession)
         var sortedContent: [Session] = []
         sessions.forEach { sessions in
             let contComp = Calendar.current.dateComponents([.year, .month, .day], from: sessions.dateModel!)
             if contComp == dateComp {
                 sortedContent.append(sessions)
             }
         }
         let newSection = Section(sectionDate: dateInSession, sessions: sortedContent)
         sections.append(newSection)
     }
 }

The problem is that whenever I add a new cell (with the same date as the previous cell), the section with the exact same date creates all over again (see the picture).

How do I fix this?

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2

Answers


  1. Chosen as BEST ANSWER
    0

    Thanks to an outside help from @OlzhasAkhmetov from MobiDev I was able to fix the repetition of sections and cells.

    The sortByDate() function required sections.removeAll() in the very beginning. The final working code of the sortByDate() is as follows:

    func sortByDate() {
    sections.removeAll() // This is what was missing
    let dates = sessions.reduce(into: Set<Date>()) { result, sessions in
        let date = Calendar.current.startOfDay(for: sessions.dateModel!)
        result.insert(date) }
    for date in dates {
        let dateComp = Calendar.current.dateComponents([.year, .month, .day], from: date)
        var sortedContent: [Session] = []
        sessions.forEach { sessions in
            let contComp = Calendar.current.dateComponents([.year, .month, .day], from: sessions.dateModel!)
            if contComp == dateComp {
                sortedContent.append(sessions) } }
        let newSection = Section(sectionDate: date, sessions: sortedContent)
        sections.append(newSection) } }

  2. 0

    In this code :

    func sortByDate() {
    let datesInSessions = sessions.reduce(into: Set<Date>()) { result, sessions in
        let dateInSession = Calendar.current.startOfDay(for: sessions.dateModel!)
        result.insert(dateInSession)
    }
    for dateInSession in datesInSessions {
        let dateComp = Calendar.current.dateComponents([.year, .month, .day], from: dateInSession)
        var sortedContent: [Session] = []
        // there you sort sessions
        sessions.forEach { sessions in
            let contComp = Calendar.current.dateComponents([.year, .month, .day], from: sessions.dateModel!)
            if contComp == dateComp {
                sortedContent.append(sessions)
            }
        }
     
        // Here you always create a new Section
        let newSection = Section(sectionDate: dateInSession, sessions: sortedContent)
        sections.append(newSection) <-- the sections array will have one more element
    }
}

    As you do not reset the sections array or update the section contains the sessions you always add a new element in the sections array. So number of sections always get +1 and filled with previous sessions + last one. This will lead to appending a new section in your table view each time you add one new session.

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