Qanday qilib balandlik cheklovini o'zgartirish mumkin, shunda sarlavhalar nolga tushadi?

Sarlashgan sarlavhani qisqartirish uchun, uning balandlik cheklovining konstantasini 0 ga o'zgartirish mumkin.

Auto Layout bilan misol:

// Sarlavha balandligi uchun IBOutlet bor deb faraz qilamiz
@IBOutlet weak var headerHeightConstraint: NSLayoutConstraint!

// Sarlavhani qisqartirish uchun:
headerHeightConstraint.constant = 0.0

// Asl balandlikni (agar ma’lum bo‘lsa) qaytarish uchun:
// headerHeightConstraint.constant = originalHeaderHeight

// Avtomatik tartibni yangilashni unutmaslik uchun, agar avtomatik yangilash ishlatilmayotgan bo‘lsa
UIView.animate(withDuration: 0.3) {
    self.view.layoutIfNeeded()
}

NSLayoutConstraint.activate/deactivate bilan misol:

// Asl balandlik cheklovi va nol balandlik cheklovi bor deb faraz qilamiz
let originalHeaderHeightConstraint: NSLayoutConstraint!
let zeroHeaderHeightConstraint: NSLayoutConstraint!

// Initsializatsiya yoki sozlashda:
originalHeaderHeightConstraint = headerView.heightAnchor.constraint(/* ... asl balandlik ... */)
zeroHeaderHeightConstraint = headerView.heightAnchor.constraint(equalToConstant: 0.0)
zeroHeaderHeightConstraint.isActive = false // Dastlab faol emas

// Sarlavhani qisqartirish:
NSLayoutConstraint.deactivate([originalHeaderHeightConstraint])
NSLayoutConstraint.activate([zeroHeaderHeightConstraint])

// Asl balandlikni qaytarish:
// NSLayoutConstraint.deactivate([zeroHeaderHeightConstraint])
// NSLayoutConstraint.activate([originalHeaderHeightConstraint])

// Tartibni animatsiya bilan yangilash
UIView.animate(withDuration: 0.3) {
    self.view.layoutIfNeeded()
}

Usul tanlovi, siz qanday qilib constraints ni sozlaganingizga bog‘liq. constant ishlatish, mavjud constraints uchun osonroq. Aktivlashtirish/deaktivlashtirish esa, constraints holatlari orasida tezda o'tish yoki bir nechta constraints balandlikni belgilashda foydalidir.

layoutIfNeeded() ni chaqirish (afzalroq, animatsiya blokida) muhim, chunki bu o'zgarishlar qo'llanib, UI ning silliq yangilanishini ta'minlaydi.