UITableView: asoslar, iOS ilovalaridagi ro'yxatlar va hujayralar

iOS da UITableView nima?

UITableView — bir ustunda aylantiriladigan qatorlar ro'yxatini ko'rsatish uchun UIKit frameworkidagi sinf. Har bir qator UITableViewCell obyekti bilan ifodalanadi. UITableView iPhone OS 2 (2008) da paydo bo'lgan va shu vaqtdan beri iOS da ro'yxatlar uchun asosiy komponent bo'lib qolmoqda. UITableView arxitekturasi MVC naqshiga asoslangan: ma'lumotlar DataSource tomonidan, ko'rinish va xatti-harakat Delegate tomonidan, ko'rinish esa jadvalning o'zi tomonidan boshqariladi.

Ikki jadval uslubi: .plain (ixtiyoriy bo'limlar bilan uzluksiz ro'yxat) va .grouped.insetGrouped qo'shilgan — chekkalardan bo'shliqlar bilan grouped-uslub, Sozlamalar va Salomatlik ilovalarida ishlatiladi. Uslub tanlovi standart ko'rinishga ta'sir qiladi: plain-jadvallar aylantirishda bo'lim headerini yuqoriga yopishtiradi (sticky header), grouped — yopishtirmaydi.

Self-Sizing Cells

iOS 8 dan boshlab, UITableView avtomatik o'lchamli hujayralarni (self-sizing cells) qo'llab-quvvatlaydi. Faollashtirish uchun tableView.estimatedRowHeight (masalan, 80) va tableView.rowHeight = UITableView.automaticDimension ni o'rnating. Jadval hujayra ichidagi Auto Layout cheklovlari asosida qator balandligini avtomatik hisoblaydi. Self-sizing murakkab hujayralar uchun ishlashni pasaytiradi — 500+ elementli jadvallar uchun doimiy balandlikdan (rowHeight) foydalaning.

UITableViewCell uslublari: basic, subtitle, value1, value2

UITableViewCell maxsus hujayra yaratmasdan 80% stsenariylarni qamrab oladigan to'rtta o'rnatilgan uslubni taqdim etadi. Har bir uslub textLabel, detailTextLabel va imageView kombinatsiyasidan iborat. Uslub tanlovi hujayra ishga tushirilganda init(style:reuseIdentifier:) orqali o'rnatiladi.

// Maxsus hujayralar bilan jadval yaratish
class ContactListController: UIViewController {

    private let tableView = UITableView(frame: .zero, style: .insetGrouped)

    override func viewDidLoad() {
        super.viewDidLoad()

        tableView.register(UITableViewCell.self, forCellReuseIdentifier: "cell")
        tableView.dataSource = self
        tableView.delegate = self
        tableView.rowHeight = 60
        view.addSubview(tableView)

        // Auto Layout
        tableView.translatesAutoresizingMaskIntoConstraints = false
        NSLayoutConstraint.activate([
            tableView.topAnchor.constraint(equalTo: view.topAnchor),
            tableView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            tableView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
            tableView.bottomAnchor.constraint(equalTo: view.bottomAnchor)
        ])
    }
}

extension ContactListController: UITableViewDataSource {

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

    func tableView(_ tableView: UITableView,
                         cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath)
        let contact = contacts[indexPath.row]

        var content = cell.defaultContentConfiguration()
        content.text = contact.name
        content.secondaryText = contact.phone
        content.image = UIImage(systemName: "person.circle")
        cell.contentConfiguration = content

        return cell
    }
}

UIContentConfiguration (iOS 14+) — textLabel/detailTextLabel ga to'g'ridan-to'g'ri murojaat qilish o'rniga contentConfiguration orqali hujayralarni sozlashning zamonaviy usuli. cell.defaultContentConfiguration() dan foydalaning yoki maxsus UIContentConfiguration yarating. Afzalliklari: dinamik tip, qorong'u mavzu va VoiceOver qutidan chiqishi bilan qo'llab-quvvatlanadi. Apple (WWDC 2024) barcha yangi UITableView lar uchun contentConfiguration ni tavsiya qiladi.

DataSource va Delegate: majburiy metodlar

UITableViewDataSource — jadval uchun ma'lumotlarni ta'minlaydigan protokol. Majburiy metodlar: tableView(_:numberOfRowsInSection:) va tableView(_:cellForRowAt:). Ularsiz jadval hech qanday qatorni ko'rsata olmaydi. UITableViewDelegate — ko'rinish va xatti-harakatni boshqarish uchun protokol: qator balandligi, tanlash, tahrirlash, contextual actions.

// Bir nechta bo'lim va tahrirlash bilan misol
extension ContactListController: UITableViewDelegate {

    // Har bir qator uchun maxsus balandlik
    func tableView(_ tableView: UITableView,
                         heightForRowAt indexPath: IndexPath) -> CGFloat {
        80
    }

    // Tanlashni qayta ishlash
    func tableView(_ tableView: UITableView,
                         didSelectRowAt indexPath: IndexPath) {
        tableView.deselectRow(at: indexPath, animated: true)
        let contact = contacts[indexPath.row]
        showDetail(for: contact)
    }

    // Swipe-to-delete
    func tableView(_ tableView: UITableView,
                         trailingSwipeActionsConfigurationForRowAt indexPath: IndexPath)
        -> UISwipeActionsConfiguration? {
        let deleteAction = UIContextualAction(style: .destructive, title: "O'chirish") {
            [weak self] _, _, completion in
            self?.contacts.remove(at: indexPath.row)
            tableView.deleteRows(at: [indexPath], with: .automatic)
            completion(true)
        }
        return UISwipeActionsConfiguration(actions: [deleteAction])
    }
}

Delegate ishlashi: o'lcham metodlari (heightForRowAt) har bir aylantirishda har bir ko'rinadigan qator uchun chaqiriladi. Teng balandlik uchun to'g'ridan-to'g'ri rowHeight ni o'rnating — bu heightForRowAt dan 10 marta tezroq. Self-sizing hujayralari uchun estimatedRowHeight va automaticDimension ni o'rnating — jadval heightForRowAt ni faqat ko'rinadigan qatorlar uchun chaqiradi, qolganlari uchun estimatedRowHeight dan foydalanadi.

Hujayralarni qayta ishlatish: reuse queue va register

Reuse queue — qayta ishlatiladigan UITableView hujayralari havzasi. Hujayra ekranni tark etganda, o'chirilmaydi, balki navbatga qo'yiladi. Yangi hujayralar noldan yaratilmaydi — tizim dequeueReusableCell(withIdentifier:for:) ni chaqiradi, u navbatdan hujayra qaytaradi yoki navbat bo'sh bo'lsa yangisini yaratadi. Bu UITableView ishlashining asosiy mexanizmidir.

// Keshlash bilan maxsus hujayra
class ContactCell: UITableViewCell {

    private let avatarView = UIImageView()
    private let nameLabel = UILabel()
    private let subtitleLabel = UILabel()

    override init(style: UITableViewCell.Style, reuseIdentifier: String?) {
        super.init(style: style, reuseIdentifier: reuseIdentifier)
        setupViews()
    }

    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    private func setupViews() {
        contentView.addSubview(avatarView)
        contentView.addSubview(nameLabel)
        contentView.addSubview(subtitleLabel)

        // Auto Layout cheklovlarini sozlash
        avatarView.translatesAutoresizingMaskIntoConstraints = false
        // ... cheklovlar ...
    }

    func configure(with contact: Contact) {
        nameLabel.text = contact.name
        subtitleLabel.text = contact.phone
        // Avatarni asinxron yuklash
    }

    override func prepareForReuse() {
        super.prepareForReuse()
        avatarView.image = nil
        nameLabel.text = nil
        subtitleLabel.text = nil
    }
}

// Ro'yxatdan o'tkazish va foydalanish
tableView.register(ContactCell.self, forCellReuseIdentifier: "contactCell")

// cellForRowAt da:
let cell = tableView.dequeueReusableCell(withIdentifier: "contactCell", for: indexPath) as! ContactCell
cell.configure(with: contacts[indexPath.row])
return cell

prepareForReuse() — hujayra reuse queue ga qo'yilishidan oldin chaqiriladigan metod. Hujayraning barcha holatini tiklang: matn, tasvirlar, animatsiyalar, yuklamalar. prepareForReuse bo'lmasa, qayta ishlatilgan hujayra eski ma'lumotlarni ko'rsatishi mumkin: oldingi tasvir yangisi yuklanmaguncha soniyaning bir qismi ko'rinadi. Apple (WWDC 2023) prepareForReuse da URLSessionTask.cancel() orqali asinxron operatsiyalarni tozalashni tavsiya qiladi.

Bo'limlar, header va footer: ma'lumotlarni guruhlash

Bo'limlar UITableView da mantiqiy bog'langan qatorlarni guruhlaydi. Har bir bo'lim header (sarlavha) va footer (pastki) ga ega bo'lishi mumkin. Bo'limlar soni numberOfSections(in:) metodi bilan aniqlanadi (standart 1). Grouped va insetGrouped uslublari uchun bo'limlar vizual ravishda bo'shliqlar va yumaloq burchaklar bilan ajratiladi.

Indekslash: bo'limlar bo'ylab tez navigatsiya uchun indeks qo'shing — o'ng tomonda ko'rsatiladigan satrlar massivi. sectionIndexTitles(for:) ni amalga oshiring — har bir bo'limning birinchi harflaridan iborat massivni qaytaradi. 26+ bo'lim uchun bu UX ni keskin yaxshilaydi. iOS 15+ da jadvallar sectionHeaderTopPadding ni qo'llab-quvvatlaydi — status bar va birinchi header o'rtasidagi zich maket uchun 0 ga tushirilishi mumkin bo'lgan bo'shliq.

UITableView ishlashi: eng yaxshi amaliyotlar

Ishlash UITableView uzoq ro'yxatli ilovalar uchun juda muhimdir. Asosiy muammolar: cellForRowAt dagi og'ir operatsiyalar tufayli sekin aylantirish (jank), heightForRowAt ning tez-tez chaqirilishi, prefetching ning yo'qligi. Apple (WWDC 2025) 1000+ elementli jadvallar uchun beshta asosiy amaliyotni ta'kidlaydi.

• Flat-height — barcha hujayralar uchun heightForRowAt o'rniga doimiy rowHeight dan foydalaning. Farq: 500 qatorli jadval uchun 60 FPS vs 30 FPS.
• Prefetching — hujayra ekranda paydo bo'lishidan oldin ma'lumotlarni (tasvirlar, API) asinxron yuklash uchun UITableViewDataSourcePrefetching ni amalga oshiring.
• Kamroq subview — contentView dagi har bir subview render vaqtini oshiradi. UIImageView o'rniga oddiy grafikalar (ajratgichlar, belgilar) uchun draw() dan foydalaning.
• Og'ir operatsiyalarni fonda bajaring — sana formatlash, lokalizatsiya, hisoblashlarni modelda bajaring, cellForRowAt da emas. Natijalar uchun NSCache dan foydalaning.
• DiffableDataSource — reloadData() ni apply(snapshot) bilan almashtiring — animatsiya bepul sodir bo'ladi, jadval to'liq qayta yuklanmaydi.

// Prefetching bilan optimallashtirish
extension ContactListController: UITableViewDataSourcePrefetching {

    func tableView(_ tableView: UITableView,
                         prefetchRowsAt indexPaths: [IndexPath]) {
        for indexPath in indexPaths {
            let contact = contacts[indexPath.row]
            ImageCache.shared.prefetch(url: contact.avatarUrl)
        }
    }

    func tableView(_ tableView: UITableView,
                         cancelPrefetchingForRowsAt indexPaths: [IndexPath]) {
        for indexPath in indexPaths {
            let contact = contacts[indexPath.row]
            ImageCache.shared.cancelPrefetch(url: contact.avatarUrl)
        }
    }
}

// Silliq yangilanishlar uchun DiffableDataSource dan foydalanish
class ModernTableController: UIViewController {

    private var dataSource: UITableViewDiffableDataSource<Section, Contact>!

    func applyContacts(_ contacts: [Contact]) {
        var snapshot = NSDiffableDataSourceSnapshot<Section, Contact>()
        snapshot.appendSections([.main])
        snapshot.appendItems(contacts)
        dataSource.apply(snapshot, animatingDifferences: true)
    }
}

Amaliy natija: ushbu optimallashtirishlarni qo'llash iPhone 12 va undan eski qurilmalarda aylantirish FPS ni 30 dan 60 ga oshiradi (Apple testlariga ko'ra, 2025). IT Sectr loyihalarida barcha yangi jadvallar uchun DiffableDataSource dan foydalanamiz va tasvirlar (avatarlar, oldindan ko'rish, ilova belgilari) bo'lgan jadvallarga prefetching qo'shamiz.