CODEWITHSUNDEEP
iosswiftuitableview
Axel
Axel

Reputation: 483

UITableViewCells disappearing

All UITableCells disappear on scroll and touch in the UITableView. Everything is done programmatically and I use the standard UITableViewCell class.

I read somewhere that the array containing my cell data may be emptied and the view can therefore not load the data on scroll. However, I don't know how to verify this.

Here is my TableView delegate and DataSource:

class LessonTable: NSObject, UITableViewDataSource, UITableViewDelegate {
    private var lessons = [LessonItem]()
    public var backgroundColor = UIColor(white: 0.97, alpha: 1)

    func addLessons(_ lessons: [LessonItem], tableView: UITableView){ 
        tableView.beginUpdates()

        //Construct array of indexPaths
        var indexPaths = [IndexPath]()
        for i in 0...lessons.count {
            indexPaths.append(IndexPath(row: lessons.count - 1 + i, section: 0))
        }

        //Append all lessons to Lessons array
        self.lessons.append(contentsOf: lessons)

        //Insert rows
        tableView.insertRows(at: indexPaths, with: .automatic)

        tableView.endUpdates()
    }

    func numberOfSectionsInTableView(tableView: UITableView) -> Int {
        return 1
    }

    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return lessons.count
    }

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "lessonCell", for: indexPath)
        cell.backgroundColor = backgroundColor

        let row = indexPath.row
        cell.textLabel?.text = lessons[row].Title
        cell.detailTextLabel?.text = lessons[row].Start.Formatted() + " - " + lessons[row].Stop.Formatted()

        return cell
    }

    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        tableView.deselectRow(at: indexPath, animated: true)

        let row = indexPath.row
        print(lessons[row].Title)
    }
}

In my ViewController's ViewDidLoad method I'm doing the following:

let upcomingLessonsTableView = UITableView(frame: CGRect(x: 0, y: 100, width: (card.frame.size.width), height: 90))
    let upcomingLessonsTableViewData = LessonTable()
    upcomingLessonsTableView.dataSource = upcomingLessonsTableViewData
    upcomingLessonsTableView.delegate = upcomingLessonsTableViewData
    upcomingLessonsTableView.register(UITableViewCell.self, forCellReuseIdentifier: "lessonCell")
    upcomingLessonsTableView.backgroundColor = upcomingLessonsTableViewData.BackgroundColor
    card.addSubview(upcomingLessonsTableView)

And also

upcomingLessonsTableViewData.addLessons(upcomingEvents, tableView: upcomingLessonsTableView)

where upcomingEvents is an array.

NEW DISCOVERY. When setting a timer that continuously prints out the contents of my lessons array, the cells doesn't disappear. Why? No clue.

Upvotes: 1

Views: 1429

Answers (2)

SP74
SP74

Reputation: 54

Make below variable as global. let upcomingLessonsTableViewData;

Upvotes: 1

Matias Jurfest
Matias Jurfest

Reputation: 1389

In your cellForRow method add this as! LessonCell your let cell line Should be like: 

let cell = tableView.dequeueReusableCell(withIdentifier: "lessonCell", for: indexPath) as! LessonCell

Upvotes: 0

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